Popular Science Monthly 1924-06: Vol 104 Iss 6

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oe 2 BS “Rep uSParOHt PERIODICAL ROOM GENERAL LIBRARY aioe SAREE SEIS nics wey ec an ortable Radio for Your Auto Vacation ; UNE .. See page 68 25 CENTS ||

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Fig RAN (RS AGAR BARAT GEERT A NTO IE ig RE RIED ARR ATE Ssapcenc nusheasiasspay au: sa, a eee a “Next to Myself I Like ‘B.V.D.’ Best” “B.V.D.” Union Suit Men’s $1.50 the suit, Youths’ 85c “B.V.D.” shaped elastic insertions at shoulders and encircling waist make these cool, loose-fitting un- dergarments instantly responsive to your slightest movement. These ever-elastic insertions are knitted by us on spring needle machines from yarns spun from selected cotton in our own yarn mill, The perfect “B.V.D.” closed crotch (patented) com- pletely covers the crotch without surplus trunk length and uncomfortable needless material at crotch or seat. The patented elastic shoulder construction and waist band reinforcement are additional guarantees of comfort and long wear. “B.V.D.” Shirts and Drawers 85c the garment “B.V.D.” Coat Cut Undershirts and Knee Length Drawers are the constant choice of millions of men who wear two-piece underwear. They know that they are correctly cut as to size and that thereisa shapeliness to the garments that make them hang smoothly and evenly with neither too much nor too little fullness. The garments are tailored with noticeable balance and drape, which they retain no matter how long worn or how often washed. 827 ba oil Waly ae By PB as Cool Men Know Why They Prefer “B.V.D.” “B.V.D.” developed an entirely new prin- ciple which completely revolutionized under dress. For its Coolness, Comfort, Long Wear and Famous Fit, “B.V.D.” is everywhere the underwear of men who demand these qualities in their Undergarments. From raw cotton to the finished garment, in every stage of manufacture, ceaseless care.assures the Unvarying Quality which has brought world wide preference for 6c B.V.D.” The cool, durable nainsook of “B.V.D.” is wovenin our own mills from selected cotton and finished in our bleachery. In our factories vigilant inspection guards every process of skilful cutting, sturdy stitching, well sewn buttons and accurate finish. There Is Only One “‘B.V. D.’? Underwear It Is Always Identified By This Red Woven Label | MADE FOR THE (Trade Mark Reg. U.S. Pat. Of. and Foreign Countries) The B.V.D. Company, inc; New York Sole Makers of “‘B,V.D.’’ Underwear ©) 1924 The B.V. D. Co,, Ins,

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In 24 Days the Crosley Model 51 Became the Biggest Selling Radio Receiver in the World! N_ Monday morning, February 4th, Powel Crosley, Jr., returned to his desk after a two week’s hunting trip _. in Mississippi. He brought with him the idea of an entirely new Radio Receiving Set to be added to the Crosley line. A short conference with his engineers fol- lowed. m Tuesday morning, February 5th, a model had been completed and tested. These sets were put into production imme- diately after the model was approved. On Tuesday afternoon, February 5th, night letters were sent to the leading distributors of The Crosley Radio Corporation announc- ing this new model which had been called MODEL 51. Wednesday afternoon, the orders commenced coming in, showing the faith of the distributors in anything brought out by this Company. Announcements were made in leading metropolitan newspapers of the country on Saturday and Sunday, Now what is this set that has made such an enviable February 9th and 10th. Shipments com- menced about February 13th, and _ were immediately followed by an avalanche of complimentary letters and orders, and have increased steadily ever since. Production started at 50 a day—was in- creased to 200—then 300—and on February 28th, just 24 days after the thought of this set had been put into being, the production reached 500 a day. Orders were received on February 28th for 1,115 of these sets—every effort being made to increase the production to 3,000 sets per day to supply the phenomenal demand for this new model. This message was written on February 29th in the face of promises of an even greater record than is indicated here. The demand for this set has not in any way lessened the sale but has alii the orders on various other models in the Cros- ley line. record, which in 24 days has, we believe, become the biggest selling radio receiving set on the market? It incorporates a tuning element made famous in the Crosley Model V, the $16.00 set u by Leonard Weeks of Minot, N. D., in his consistent handling of traffic with the MacMillan Expedition at the North Pole; a genuine Armstrong regenerative tuning and detective circuit. Now, to this has been added a one stage of audio frequency amplification. With the well-known Crosley Sheltran 9 to | ratio transformer, giving an unusual volume. Thus, this set uses 2 vacuum tubes. It is the ideal all-around receiver. For local and nearby broadcasting stations, it will operate a loud speaker, giving phonograph volume in the home. Under reasonably go receiving conditions, it will bring in stations

THE CROSLEY RADIO CORPORATION up to 1,000 miles, with sufficient volume for the average sized room. When receiving conditions are bad, however, head phones should be used on distant stations. This Receiver is unusually selective—it in- ‘corporates standard sockets so that all makes of tubes can be used. The various units are mount on beautifully engraved grained a and mounted in a hardwood, ma- ogany finished cabinet, which completely encloses all parts and tubes. A gg at this beautiful instrument sells it, and the results it gives creates many friends for it. Perhaps the most startling thing of all is its price—$16.50. Add 10% West of the Rocky Mountains. Licensed under Armstrong Regenerative Patent No. 1,113,149. Powel Crosley, Jr., President F Formerly The Precision Equipment Company and Crosley Manufacturing Company 617 ALFRED STREET CINCINNATI, OHIO

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Popular Science Monthly Most Wonderfully Illustrated Magazine in the World JUNE, 1924; Vol. 104, No. 6 25 cents a Copy; $2.50 a Year Published in New York City at 225 West Thirty-ninth Street In the July Issue David Belasco recalls his 40 years of inventive experiment in producing the ideal stage illumination, “‘a true semblance of sunshine.” A delightful article by the dean of American theatrical producers, con- taining useful suggestions for lighting the home attractively. It’s Presidential Year. For the first time in history the thrill of the big party conventions, the speeches of candidates, the views of statesmen, all will be carried first hand, far beyond the limits of con- vention halls and platforms, to a vast audience of men and women voters. A timely article next month will open your eyes to the tre- mendous part that radio, the new campaigner, will play in nominating and electing our next President. Other articles in the same issue will help you keep in step with the swift progress of radio science. Automobiles that fly soon may carry you to work every morning. So says Capt. E. V. (“Eddie”) Rickenbacker, Ace of Aces in the World War, and now a successful automobile manufacturer. Captain Rickenbacker’s fascinating predictions of the winged motor car are based on spectacular years of experience as auto race driver, army flier, and automobile designer. They are embodied in an article he has prepared for the July issue. Not one in 200 families knows how to eat right! That astound- ing conclusion, drawn from an actual canvass of 200 American dinner- tables, comes from Walter H. Eddy, Ph.D., Professor of Physiological Chemistry, Teachers College, Columbia University, and one of Amer- ica’s foremost authorities on diet and nutrition. In an unusually helpful article Doctor Eddy not only translates into understandable language the principles of scientific nutrition, but he shows how easy it is to eat the food you like in a way that will make you healthy and happy. And more than 200 other fascinating articles and pictures giving you all the news of science and invention, together with practical ideas for radio, the automobile, the home, the home workshop, and the use of tools and machinery. David Belasco and his staff or electricians in the lighting ** laboratory ”’ of the Belasco Theatre, New York POPULAR SCIENCE MONTHLY Issued monthly. Single copy, 25 cents. Yearly subscription to United States, its possessions, and Canada, $2.50; foretgn countries, $3. Entered as second-class matter Dec. 28, 1918, at the Post Office at New York under the act of March 3, 1879. Entered as second-class matter at the Post Office Department, Canada. Printed in U.S.A Copyright, 1924, by the Modern Publishing Co. See The contents of this magazine must not be reprinted without permission. In presenting in its editorial columns numerous stories of new products of applied science, POPULAR ScIENCE MONTHLY does not underwrite the business methods of the individuals or concerns producing them. The use of PopuLAR SCIENCE MONTHLY articles, or quotations from them for stock-selling schemes is never authorized. H. J. Fisher, President R.C. Wilson, Vice-President O. B. Capen, Secretary and Treasurer In This Issue Page Six Greatest Engineering Feats..... 25 Selected by Ralph Modjeski Wonders at Your Doorstep........ 28 BACT SCER DY MAGI. cic she 5s css ees 30 By Norman C. McLoud The Secreto the Giants...........5. 31 By Prescott Lecky Science Purifies Your Drinking Water 33 THE POPULAR SCIENCE INSTITUTE OF Se ee re eee 34 Announcing a new service Driving the Store to Your Door.... 36 By Lynn B. Dudley A Poor Man's $250,000 Gift to Science 37 By W. D. Thomson New Discoveries in Science......... 38 World Fliers Ready for Emergency.. 40 By Corley P. McDarment Nature’s Magic in Radium......... 41 By Raymond J. Brown Adventures in Home Ownership.... 44 By Phil M. Riley Automobile Carried by Two........ 46 Apartment Mailbox... ......0.....5 46 A Mechanical Traffic Cop.......... 46 Shoe Rack Attached to Closet Door.. 47 Smallest Coupé on Bicycle Wheels... 47 Chimney Salvaged by Angle Irons... 47 Metal Strip Alines Typist’s Paper... 48 Powerful Headlight in Two Colors... 48 Odd Designs from Cancelled Stamps. 48 One-Man Dragsaw Fells Trees...... 49 Screwdrivers and Hammer in One... 49 Elastic Roadside Fence ............ 50 Burglar Protector for Door Lock.... 50 Tunnel Building Underthe Hudson.. 51 Truck, Tractor, and Crane Combined 51 Lather Gun Replaces Shaving Brush. 51 Lumber for a House in One Log..... 52 A Powerful New Pipe Wrench...... §2 Machine Makes Butter in 30 Minutes 52 Tides Used to Move Old Bridge..... 5 Cold Sealing-Wax Squeezed from Tube 53 Improved Bicycle Brake........... 53 New Inventions for the Household... 54 Marine Pests Bore into Piling....... 56 An Odd Tree-Climbing Fish........ 56 Giant Rivals of the Potato......... 56 Powerful Beacons to Guide Aviators. 57 Machine Talks with Electric Voice... 57 Workmen's Efficiency Analyzed..... 57 Unsinkable Canoe forthe Camper... 58 Airplane Propeller Drives Motor-Car 58 The World’s Official Clock.......... 58 Hudson Maxim Still Young at71.... 59 Electricity for Edison’s Birthplace... 59 Midget Engine Drives Model....... 59 Life Raft Serves as Duck Blind...... 60 Automatic Landing Netfor Fishermen 60 Spruce Limb as Weather Prophet.... 60 Garden Tool Performs Three Tasks.. 61 Sailor Makes the Wind Saw Wood... 61 New Tool for Opening Wrappers.... 61 The World’s Greatest Powder Blast.. 62 Monoplane like Helicopter.......... 62 “‘Crawlers’’ to Double Tractor’s Pull. 63 Fishing Engine Pullsinthe Big Ones. 63 Divers Telephone from the Depths... 63 Excavator Walks 30 Feet a Minute... 64 How Much Science Do You Know?.. 64 A Light Cultivator forthe Garden... 64 Walking Radio Receiver........... 65 Safeguarding the Morning Milk..... 65 Automatic Secretary Records Calls.. 65 Your Garden inthe Summer........ 66 By Ernest Bade, Ph.D. An Ideal Portable Radiw Receiver... 68 By Joseph Calcaterra Radio by the Roadside............ 69 By Jack Binns America’s Fastest Growing Sport.... 71 By Leslie V. Spencer, M.E. When Your Car Is Stuckinthe Mud. 72 New Ideas for the Folding Camp.... 73 Repair Kinks for Motorists......... 74 The Home Workshop....... 75 Better Shop Methods....... 80 And other timely articles and pictures

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AAGKne AWTS ee POPULAR SCIENCE MONTHLY SUMNER N. BLOSSOM, Editor June, 1924 Ralph Modjeski is eminently qualified to judge the world’s great achievements in engineering, for in this field he has won a place as commanding as that which his mother, the celebrated tragedienne, Helen Modjeska, occupied in the theatrical world. Born in Poland in 1861, Mr. Modjeski came to America in 1876. During his remarkable career he has built some of the most important bridges in the United States. Also he was one of the en- gineers who constructed the world’s greatest span— the Quebec Bridge. shown above nearing com- Ralph Modjeski pletion. He now is chief engineer of the Delaware River Bridge at Philadelphia, Pa., which will have the longest span ever built in the United States Six Greatest Engineering Feats Selected by Ralph Modjeski TTEMPTING to select the six greatest engineering achieve- ments of modern times is like trying to name the six greatest men of history. Any list one might make is bound to be merely a reflection of personal opinion, which is quite likely to be influenced by prejudice or individual standards of judgment. - Ten, twenty, probably a hundred times that number of undertakings that have been completed by engineering science during the course of my life must be called great because of their vastness, their difficulty, or the benefits they have brought to mankind. The last half century has seen engineer- ing keep pace in many parts of the world with the progress made in other branches of science. Bridges, canals, power and irrigation projects, roads, docks, water- works, tunnels, cuts, and other features of railway construction, subways and sky- scrapers have followed one another with bewildering rapidity, each new work surpassing in magnitude, cost, and daring those that preceded it. That is why neither size, cost diffi- culties surmounted, nor even benefits accruing to man, supply an infallible measure of the ‘‘greatness’’ of engineering projects. One must take into considera- tion also the time at which the under- taking was prosecuted. For in engineer- ing, things that were “impossible” or exceedingly difficult 50 years ago, or even 20 years ago, are accomplished as a matter of course today by means of improved machinery and increased skill and knowledge. And so, if I am to select the six engineer- ing works that, in my opinion, are the greatest that have been accomplished in modern times, I must include those that were highly remarkable at the time they were completed, even though subse- quently they have been surpassed. The six are, in order of time: HE Suez Canal The Firth of Forth Bridge, near Edinburgh, Scotland The Assuan Dam in Egypt The Panama Canal The Roosevelt Dam in Arizona The Quebec Bridge over the St. Law- rence River. 25 Sn ne cadet aati we ee in ete 2 ‘pact em eeNET 2 aol apt aie ee ates ro pe a rn ea

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SPIE T Re Rade ass eased beside sake aii Se eR eae a eee et a ate a ’ 26 I cannot say truthfully that I re- member the construction of the Suez Canal, for it was begun April 25, 1859, two years before I was born. I do, how- ever, remember its formal opening on November 25, 1869. Few events that I ean recall aroused such tremendous enthusiasm as the passage through the canal on the following day of 56 vessels, headed by the French Imperial yacht L’ Aigle carrying the Empress Eugénie. HERE was scant wonder that the completion of the canal captured the imagination of the world. It was un- doubtedly the most stupendous engineer- ing achievement the people of that time had known, and it had been carried to success in the face of harrowing diffi- culties—natural, financial, and those reared at the outset by adverse public opinion. It was a project as old as history, for archeologists say that Seti, father of Rameses the Great, in the fourteenth century before Christ, began a canal and pushed its construction 60 miles before relinquishing his plan. Almost every ruler of Egypt from that time to the days of Napoleon Bonaparte had considered the possibility of digging a canal through the Isthmus of Suez. It remained for Ferdinand de Lesseps, a young Frenchman, to obtain the necessary concessions and to raise suffi- cient funds to undertake construction. Some idea of the difficulties that con- fronted de Lesseps may be obtained from the fact that the newspapers of 1858 called his attempt to finance the canal project a “swindle,” and that he was unable to obtain funds in the United States, England, or Russia. All of his The Assuan Dam, which impounds the waters of the mighty Nile, irrigating the Valley of the Nile in Egypt for a total distance of 700 miles. Built 22 years ago, this great engineering structure still remains the largest project of its kind ever undertaken POPULAR SCIENCE MONTHLY original capital of 200,000,000 francs was subscribed in France, Turkey, and Egypt. The Suez Canal extends from Port Said, where construction began, to Suez. It is 100 miles long; yet by connecting the Mediterranean with the Red Sea, it brings the Occident 10,000 miles closer to the Orient—a great commercial advantage. The Firth of Forth Bridge, . near Edin- \ =. burgh, Scot- : land. Note the huge tubular girders As originally con- structed, the canal’s depth averaged about 25 feet. It was about 75 feet wide at the bottom, and its breadth at the waterline ranged from about 160 feet to a little more than 300 feet. Vessels could pass one another only at certain crossing places. In 1876, though, the work of improving the channel was begun. This work has continued up to the present day and now the channel, in every dimension save the length, is virtually twice as large as when first constructed. Once it required 36 hours for a vessel to pass through. Now passage is effected in less than half that time. T° DIG a Suez Canal today would be a relatively simple task. Modern engineering skill and machinery probably would shorten by half the time required for construction. But the builders of the Suez Canal were forced to acquire their own skill and their own experience and to develop their own machinery as they went along. They were pathfinders. They contributed a great achievement to en- gineering history and a mighty aid to commerce, and marked a new era in the world’s progress. That is why I must call the building of the Suez Canal one of the greatest feats of engineering in the history of the world. To those who would say that the Panama Canal is a greater monument to engineering skill than its predecessor across the Isthmus of Suez, I can only reply that the Panama Canal undoubtedly is the most tremendous engineering achievement of all time. It does for the New World what the Suez Canal did for the Old—unites the East and the West, though on a scale vastly more lavish. In fact, the Panama Canal was an undertaking of such heroic proportions that the result is more than an engineering achievement. It is one of the new won- ders of the world. But it was completed almost a half century after the Suez Canal was built, and in the interim the science The Roosevelt Dam, completed in 1911, in Salt River Valley, near Phoenix, Ariz. Located at the mouth of a canyon, it is a huge quarter circle of sandstone and cement, 280 feet high and 168 feet thick at the base, most impressive, and surmounted by a 16-foot roadway. It is exceeded in size only by the Assuan Dam _ hn Se so =

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2a mn ly he eir nd ey ey n- he all he ry che sor of engineering had made such giant strides that the problems of its builders were enormously simplified in comparison. It supplies the most striking illustration we have of the progress that was made in engineering in the nineteenth century, for de Lesseps, builder of the Suez Canal, attempted to construct a Panama Canal following his first triumph and spent $300,000,000, only to score the most co- lossal failure in the history of engineering. The Right Hon. James Bryce, later British Ambassador to the United States, called the Panama Canal “the greatest liberty man ever took with Nature.” I cannot hope to add anything to that statement. HIRTEEN years after the completion of the Suez Canal there was begun in Scotland the greatest project in bridge con- struction that man ever had attempted— the Firth of Forth Bridge. A vivid idea of the immensity of this structure is given by the statement of Sir Benjamin Baker, its builder, that it compared in size with the largest bridge previously built in Great Britain as a Grenadier Guardsman compared with a newborn child. From bank to bank at the site of the bridge the Firth of Forth measures 8091 feet—more than114 miles. Foundations for the viaduct approaches had to be sunk in water almost 200 feet deep, a tre- mendous detail in itself. The bridge is of the cantilever and central girder type and, but for the fact that the central cantilever could be placed partly on the Island of Inchgarvie, which stands about halfway across the Firth, it is unlikely that con- struction would have been possible. And Ps. Sige am The Roosevelt Dam is designed to store the flood waters of Salt River and Tonto Creek for the irrigation of 240,000 acres of land in Salt River Valley. The reservoir has a capacity of 1,284,000 acre feet, enough water to cover the state of Delaware to a depth of one foot. It has made vast wastes available for farming POPULAR SCIENCE MONTHLY yet, even with this aid supplied by Nature, the two main spans each are 1700 feet long—almost a third of a mile. These were the longest spans built anywhere in the world until the Quebec Bridge was constructed, more than a quarter of a century later. The Firth of Forth Bridge was com- The Suez Canal, 100 miles long, con- y/ necting the y/ Mediter- / ranean / ee andthe / 5 Red Sea pleted late in 1889, and formally opened by the Prince of Wales, after- ward King Edward VII, on March 4, 1890. The huge tubular girders used in its construction give to it a peculiar appearance cf stability that is borne out by the service it has given through almost 35 years. The bridge has a clearance of 157 feet Enormous locks of the Panama Canal, showing the U. S. battle- ships Delaware and North Dakota floating abreast in the great waterway that Mr. Modjeski calls the most tremendous engineering achievement of all time—one of the new wonders of the world 27 above high water and its central tower rises 150 feet higher. Marked ingenuity was used in its construction. The rolled material for the structure was taken to the site and fitted into place piece by piece as a steel ship would be built, thus obviating the necessity for heavy ma- chinery and lifting apparatus to place the materials. As a feat of engineering, the construc- tion of a bridge like this would be note- worthy, even at the present day. At the time it was built it marked an epochal advance in engineering. THat the Quebec Bridge, which crosses the St. Lawrence River in Canada, is more massive and has a clear span 100 feet longer than that of the Forth Bridge in no wise detracts from the glory won by the builders of the great structure in Scotland. For the Quebec Bridge was completed almost 30 years after the Forth Bridge, and, as in the case of the Suez Canal and the Panama Canal, engineering skill and knowledge had advanced with the intervening years. It was my privilege to aid as a member oe —— of the board of engineers in the construc- tion of this greatest bridge of recent years, which was completed in 1917. Its center span of 1800 feet still is the longest ever built. It is the heaviest, too, for, owing to the increase in size and weight of locomotives and railway cars, it was necessary to build the Quebec Bridge strong enough to withstand a stress 214 times greater than that which can be borne by the Forth Bridge. It is interesting that Sir Benjamin Baker, besides contributing the Firth of Forth Bridge, was associated eight years (Continued on page 126) SS

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— ae CAM EIA T BRIO te cpirenons Pe PRT POPULAR SCIENCE MONTHLY Wonders at Your Doorstep Three baby Blue Jays. When Doctor Pardoe took this picture, the parent bird, with amazing imitation, gave the call of a hawk, apparently hoping to frighten him away A common Garter Snake with 57 young, one day old. Some snakes lay eggs, while others, like this one, bring their young into the world alive, the former being called “oviparous” and the latter “ viviparous” and spend small fortunes in search of the world’s thrills and wonders. Yet others have learned to find never- ending adventures right at their own doorstep or in near-by fields and woods, where they are forever liscovering new marvels of nature in things that most of us pass by as commonplace. Such a person is Dr. Jonathan B. Par- doe, of Bound Brook, N. J., a dentist by profession and a naturalist by hobby. Since he was a barefoot boy of 10, with a camera and a Gordon setter, he-has spent Gina of us travel thousands of miles A young Green Heron on its nest. The Heron builds in colonies commonly known as rookeries. Its home, usually near a pond or river, is con- structed of a few sticks loosely woven together, located about 25 feet from the ground. Its food consists mainly of small fishes, tadpoles, and _ snails Dr. Jonathan B. Pardoe, during a jaunt, making friends with baby High-Holders every spare moment roaming the fields and woods, watching the exciting daily events in the busy world of beast, bird, and insect, and recording these events in remarkable photographs. He has felt the teeth of an angered opossum. He has watched the courageous king bird battle to victory against the mighty hawk. He has spied upon the timid wren, entering her nest in the end of a hollow tree limb. He has come upon a deadly rattler swallowing a brother snake. He has seen how a mother garter snake cares for her 57 young. He has helped a beleaguered land turtle to rid itself of a seething army of black ants; and he has been surprised by a snapping turtle oddly camouflaged with mud and grass against its enemies. “Jack and Jill.” Jill, the crow that Doctor Pardoe raised and tamed from babyhood, became the inseparable companion of Jack, his dog Baby High-Holders, holding on high. The grown birds are skilful carpenters, drilling their homes in decayed trees. They are known also as Golden-Winged Woodpeckers Here is a common Snapping Turtle that has skilfully camouflaged itself with mud and grass as a protection against its enemies. This is just one of many strange sights Doctor Pardoe encounters in his walks Doctor Pardoe has found, too, that birds make ideal pets. Four baby owls that he brought home from one of his jaunts became so tame that they would perch on his shoulder! Likewise he tamed a young crow that became the inseparable friend of his dog and would ride around on the dog’s back, joining the chase for squirrel or rabbit. All these adventures, and many more like them, Doctor Pardoe has preserved in photographs, some of which are repro- duced here. He says any one of us can find things just as interesting. Jenny Wren, with a spider in her bill, about to enter her nest in the end of a hollow limb. Many days of patient waiting were re- quired to make this remarkable snapshot. The little bird also fed her young with grasshoppers, caterpillars, moths, and larvae of different and tempting kinds

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a ae ow ™@@ shat wis uld med able und for Lore ved or 0- can ww wl Ss FF Tree Frogs, sunning themselves on their “front porches.” As their name implies, they live in trees, and they have the power of stick- ing to almost any surface with their feet. Usually they give their calls at night, and especially when rain _ is threatening The Garden, or Ladder Spider, onits web. It is known also as the River Spider. Usually it builds its web along river banks in the tall grasses. The name Ladder Spider is derived from the sturdy, ladder-like structure that it spins across the center of the silken web These three baby Screech Owls were brought home by Doctor Pardoe from one of his jaunts, After he had tamed them, he perched them on an old straw hat, attracted their attention with a butterfly moth, and snapped the picture POPULAR SCIENCE MONTHLY A large Snapping Turtle hanging by its jaw. The turtles usually are found in muddy streams. Often they catch young ducks by pulling them under water, drowning them Here is a Fish Hawk hovering above its nest at the top of an electric light pole. Usually this great bird builds its nest in a tall tree, but in some instances has been known to build on rocks a few feet from the ground The remarkable photograph below shows six stages in the development of the Cicada, or Seventeen-Year Locust. After a prolonged exis- tence underground, the pupa (at the extreme right) emerges and sets free the perfect winged insect through a slit in the thorax, as shown out of the door of his home. The trick that has made him famous is to “play dead’? when at- tacked. He generally is believed to be dull- witted, but at times he is surprisingly agile. Doc- tor Pardoe declares he is superior to a cat in his skill as a _ rat-catcher A Screech Owl and its young. Doctor Pardoe found these birds very easy to tame. One evening, while sitting in his study with the window open, he called. In reply, his pet owls flew through the window and perched on his shoulder, where they sat, blinking solemnly Above is a magnificent Pole- phemus Moth, just emerged from its cocoon. The cocoon often is found on young white- birch trees. When warm weather comes, the moth emerges by eating a hole in the top. Its folded wings soon dry and spread in a colorful display pa one peers areata : rh a ore Dg 2

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POPULAR SCIENCE MONTHLY | He Sees by Radio C. Francis Jenkins of Washington, D. C., inventor of the motion- picture projector, demonstrating his latest achievement—an ap- paratus for transmitting pictures by radio. In transmission, a pencil ray of light passes through rotating glass disks of graduated thickness, which bend the rays and cause them to oscillate. These N A laboratory in Washington, D. C., a few weeks ago, I had the extraor- dinary and positively uncanny ex- perience of talking face to face with a man who was actually in a room at another end of the building. His voice came to me over the radiophone, but for a few seconds I saw him in life size and full detail on the white wall in front of me. No spiritualist’s séance could have pro- duced an effect more weird than this of seeing a man whom I knew to be half a hundred feet away from me and screened from my sight by substantial walls. And yet I knew that in reality there was nothing mysterious about it. Only a few minutes earlier the man whose ghostly image looked down on me from the wall had explained to me exactly how he was able to project himself through solid woodwork and plaster. For the amazing thing I was witnessing was merely a dem- onstration of a new wonder of science— radiovision, developed by C. Francis Jenkins. This invention is not a method of trans- mitting moving-pictures by radio. Al- though it makes the transmission of movies possible, the camera is not used. Rather, what Jenkins has devised may be described as a sort of supertelescope, one whose field of vision is neither dimmed by distance nor obscured by barriers; a contrivance that makes it possible to view far-away events the instant they take place, just as the radio permits us to hear distant sounds as they occur. The apparatus still is in the experi- mental stage. Jenkins does not claim perfection for it yet. But so confident is he of success in the near future that he already is planning a dramatic public The Dramatic Achievement of a Great Inventor Who Wouldn't Stay Discouraged By Norman C. McLoud demonstration. He intends to have a deaf-and-dumb man in Boston hold a conversation in the sign language with a deaf-and-dumb man in Washington, thus giving to the deaf mutes their first tele- phone. After that, he says, it will be only a short time until sporting events and other public spectacles will be broad- cast for the eye, precisely as descriptions of them now are broadcast for the ear. No doubt you are more or less familiar with the name of C. Francis-Jenkins, but you probably do not know that he holds an indisputable right to be numbered among America’s great inventors. It was he who invented the moving-picture pro- jecting machine 30 years ago, thereby changing the movies from a child’s toy into an instrument of vast commercial, artistic, scientific, and educational value. gs invention brought Jenkins very little fame, and no money at all. In fact, his experiments plunged him into debt. The world of science, however, has accorded him recognition. He bears the unusual distinction of having been honored twice by the Franklin Institute of Philadelphia for his invention. One of his choicest possessions is a letter from Alexander Graham Bell, inventor of the telephone, praising him for his early motion-picture projecting machine. But fate played a strange prank in denying to Jenkins recognition from the public, to whom undoubtedly moving pictures have meant most. Jenkins, though, has accepted this fact with a complacency that is characteristic. ““My projecting machine,” he told me, “represented more than four years of persistent effort. When I first demon- Above is a photograph of the late President Harding after it had been transmitted by radio 135 miles from Washington, D. C., to Philadelphia, Pa. The transmission was ac- complished in three minutes by the newly invented apparatus shown at the left oscillating rays ultimately cover the picture to be transmitted, and are modulated. The modulated waves then strike a light- sensitive photo-electric cell, and are transformed into radio waves of corresponding variation. The radio impulses thus transmitted are reconverted into light waves by a machine strated it in 1894, there was not another device like it in the world. After the pub- lication of the details of my method two years later, machines of the same kind sprang up like mushrooms, and within 20 months three times as many patents for moving-picture apparatus were issued as had been granted in the 30 years preced- ing. “yen I realized that my invention was going to pay me only in self- satisfaction, I did what many people would regard as a strange thing. At the time I was secretary to Sumner I. Kimball, executive head of the United States Life- Saving Service. My salary was $1600 a year; good pay in those days. But I gave up my job to devote my entire time to invention. I was determined to make a go of invention or starve trying. Well, I haven’t starved, neither have I been cured of the inventing habit.” “So you must have made a go of it?” I suggested. “That depends on how you look at it,” said Jenkins. “I have some wealthy friends who are frankly sorry for me be- cause I haven’t made as much money as they have. However, I’ve taken out more than 300 patents, I’ve had plenty of inter- esting experiences, and some of my inven- tions probably have lightened the burden of some of my fellow men. “Most of my inventions were pot- boilers—things I sold for from $250 to $2500 to give me a living and pay for the greater things I had in mind. A motor- driven lawnmower, an automobile tire chain, and a check protector probably are typical. (Continued on page 128) ~-_~_-se.amioeem ne ode & 9 68 & Ue.

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POPULAR SCIENCE MONTHLY 31 The Secret of the Giants Strange New Facts about Glands—Tiny Drug-Stores of Your Body By Prescott Lecky Department of Psychology, Columbia University GIANT from the backwoods, A arriving in Hollywood recently to begin his career as a motion-picture actor, furnished the newspapers with a sure-fire humorous story that set the nation grinning. For the giant, in order to accommo- date his architecture to the limitations of a Ford car, had cut a hole in the top and protruded his head and neck: through the aperture! No doubt we shall see him in slapstick comedy before long; and whether he is a comedian or not, undoubtedly he will succeed in entertaining us. He is a giant, and that is enough. Giants have been a source of wonder since the dawn of history. We think of the giant as a superman, which is only one step removed from thinking of him as supernat- ural. Somehow he seems in- explicable in natural terms. But now the mystery of the giants is going the way of other mysteries; for science has found the key to gigan- tism. The key lies in a few bits of tissue so small that they can be held in the hollow of your hand, yet so important that they even may unlock the innermost secrets of the proc- esses of life and death. Scat- tered about the body—in the head, neck, and trunk—these unimportant - looking _ little granular masses in reality are tiny chemical laboratories—a whole chain of bodily drug- stores, dispensing wonder- working remedies of their own manufacture. © NEW are they to the sci- entific world that they still are known by three dif- ferent names—‘‘endocrin or- gans,”’ “ductless glands,” and “the glands of internal secre- tion.” They empty their secretions directly into the blood vessels that nourish them, and so are distin- guished from the so-called duct glands, which pour out their secretions through tubes or ducts and deposit them upon either the inner or outer surfaces of the body. The important ductless glands are the pituitary, pineal, thyroid, adrenal, gonads, thymus, and the island cells of the pan- creas. ‘The wonder-working remedies they secrete are known by two names—‘‘auto- coids,” meaning “self-drugs’”; and “hor- mones,” meaning to arouse or stir up. They act as body accelerators, and some- The world’s small times as body brakes. The power of their action on the body passes belief. Through the discovery of the locations and functions of certain of these body chemical laboratories, great research laboratories are writing a new and mar- velous drama of science. It is a tale not only of giants, but of midgets as well; also of fat ladies and is unfolding in a few small glands promises to become, when completed, the most important body of information, from a human standpoint, yet discovered. Consider, for example, the single item of insulin—one of the autocoids, or chemical secretions, which Doctor Bant- ing extracted from certain glandular cells of the pancreas. In the few short months since its discovery, practi- cally every other diabetes remedy on the market, along with much of the old-fash- ioned medical procedure, has been thrown into the*discard. What does this mean for the future? What will be the fate of our concoctions and patent medicines in use today? What will drug-stores carry on their shelves 20 years from now? va UCH of the evidence concerning the func- tions of the ductless glands has been obtained experi- mentally by administering to the human body secretions taken from the glands of animals. In some cases an entire gland has been grafted into the body. Other evi- dences come from clinical cases in which over- or under- secretion of the glands can be demonstrated. These observations and ex- periments offer a basis for be- lieving that before long it may be possible to grow giants experimentally (pro- vided, of course, any one wished to be a giant!), just as botanists grow giant plants. Note the word possible. This experiment never has been attempted on a human being, and probably never will be. But even with the elementary knowledge and _ technique now available, such experi- ments performed upon dogs and other animals have shown human skeletons. And it goes even further, concerning itself vitally even with the water you drink, the food you eat, and the medicine your doctor may subscribe. You have seen in the papers recently that large cities are considering the matter of putting iodin into the city water. That is part of the story. So is the recent advice of the United States Bureau of Fisheries that you should eat more salt fish. So is the discovery of in- sulin, the wonderful remedy for diabetes, by Dr. Frederick Grant Banting, of Toronto, Canada. In short, the drama of life that science est bellhop, Dee McLain, is seen showing John Aason, Los Angeles giant, to his room in a New York hotel. Each man is just 24 years old, but John is a little more than eight feet tall, while Dee measures just three feet. the giant and midget are the result of overdevelopment and underdevel- opment of the pituitary gland, an insignificant-looking lump of tissue Science now believes that ' some measure of success. Perhaps our children or grandchildren may see dogs as large as horses produced by this means. This, too, is speculation; but remember that lizards grew to be 50-foot dinosaurs. One of the main sources of such scien- tific romancing is the pituitary gland, an insignificant-looking button of | tissue, somewhat smaller than the end bone of your little finger, known as “‘the gland of the giants.” It is situated just back of the root of the nose in a bony socket of its own—a skull within a skull. Few if any parts of the body are so carefully fortified against accident and injury, and with good reason, for its removal invariably causes death. The gland consists of two lobes, an anterior, or front lobe, and a posterior or back lobe.

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32 Each has a different function. Now the anterior lobe of the pituitary, small as it is, seems to dominate the bony growth in the body and regulate the size of the skeleton. An oversecretion of this lobe causes the bones to grow with astonishing rapidity, and this is the cause of gigant- ism. An undersecretion, on the other hand, prevents the growth of bone and results in one form of dwarfism. Many lines of evidence lead to this conclusion. In the first place, in the few dwarfs who have been available for X-ray study, the pituitary was found to be ex- ceedingly small and wasted. Studies of giants, on the other hand, have shown in- variably an abnormally large pituitary. The most con- vincing evidence, my however, is to be F found in actual clinical cases where excessive pituitary secretion from natural causes can be dem- onstrated. The story of John Turner, reported by Dr. Harvey Cushing of Har- vard, is a typical example. At the age of 15, John Turner began to grow rapidly. He developed a tremendous appe- tite, and is said to have-taken a pint POPULAR SCIENCE MONTHLY glands, a large, well-nourished brain is another pituitary characteristic, so much so that the pituitary has been called the gland of intelligence. Lincoln is a good instance of the normal pituitary type. Other glands influence growth also, though indirectly. Moreover, all the glands work together, retarding or acceler- ating one another, as the case may be, and the total result is a compromise or balance. That is why the research work goes forward so slowly. It is also a good thing to bear in mind when you read advertise- ments offering various gland extracts as fat-reducers, ‘‘pep-makers,” etc. Most drugs are like popguns—they make their little noise and not much happens. But Where Do You Live—How Tall Are You? conditioned by the productivity of our glands of internal secretion. The pituitary gland is suspected of other interesting functions. It is believed, for example, to be the agency that pre- serves in the blood the same proportion of salt that there is in sea water; our original blood, according to the theory of evolu- tion, having been sea water itself. That is why you are urged to eat salt fish. The pituitary, or its forerunner, is present in marine organisms as low as the starfish. PERSONS in whom the pituitary gland is underdeveloped are characteristi- cally drowsy, with low power of assimilat- ing food, subnormal temperature, slow pulse and _ insen- sitivity to pain and emotional stimuli. These also are the characteristics of hibernating ani- mals, and it has been found that the pituitary in such animals grad- ually shrinks as the period of hi- bernation ap- proaches, and en- larges when the animal awakens. We are not sur- prised, therefore, to hear it sug- gested that the periodic exhaus- tion of the gland may bear some re- of whisky regu- lation to the enig- larly for breakfast. ma of sleep. He shot up to a @™ 6640-6726 WZ 67.27-67.75 Ea 67.76-68.11 () 68.12-68.67 It is believed height of eight maid on Gilineien Gt Ont eat teene further that the feet three inches. When he went toa hospital at the age of 36, suffering from an _. over- growth of the knee joints, his weight was found to be 275 pounds, in spite of extreme emaciation. His hands and feet were enormous. He wore a child’s undershirt for a sock, and his shoes were 15 inches long. The bones of the face were so overdeveloped that the ears were located far to the rear of the head. The brain was weighed after death and found to be of gigantic proportions, weighing 4 pounds, 214 ounces, or 1884 grams, believed to be the largest on rec- ord. (The average brain weight is 1400 grams.) zo a aeINATION showed the pituitary enlarged to several times the normal size. When the pituitary begins to over- secrete in later life, the bones thicken but do not lengthen. This example represents abnormal ex- tremes, but there are many normal men of the pituitary type who share the same characteristics in lesser degree. Such men have large bones with heavy joints, especially noticeable in the hands and feet. The teeth also are large, and the nose, jaws, and other features prominent. Often the arms and legs are hairy. Unless offset by abnormalities in other American in height. smallest. shows how man’s stature varies in different sec- tions of the United States. The key figures be- low the map indicate height in inches. If you are five feet seven inches tall, you are an average North Carolina has the tallest men on the average; Rhode Island the The stature in rural districts, as a rule, is above that in cities and the tallest popu- lations prevail in the mountain districts of the South and in Arkansas, Kansas, Texas, and Oklahoma. The large black and shaded dots endocrin extracts are heavy artillery, and the amateur will do well to leave the bom-. bardment to experts. Thus, in spite of the Chinese wall that nature has built around them, the secrets of the pituitary are slowly being solved, even though as yet we have caught only a glimpse of their wonders. As experi- mental work accumulates, the evidence grows more convincing. If we are indeed approaching a new era in medicine it well may be called the age of the endocrins. “More and more,” says Dr. L. F. Barker of Johns Hopkins, “are we forced to realize that the general form and ex- ternal appearance of the human body de- pends, to a large extent, upon the func- tioning, during the early developmental period, of the endocrin glands. Our stature, the kind of faces we have, the length of our arms and legs, the quantity and location of our fat, the amount and distribution of hair on our bodies, the tonicity of our muscles, the sound of our voices, and the size of the larynx, the emo- tions to which our exterior gives ex- pression—all are to a certain extent indicate New York, Philadelphia, Boston, Buf- falo, Detroit, Chicago, Milwaukee, Cincinnati, St. Paul, St. Louis, New Orleans, Denver, Los Angeles, and San Francisco. Note that all of these cities fall within the classifications of short or medium stature. The map, prepared by Dr. Clark Wissler, of the American Museum of Natural History, would indicate on the whole that, other things being equal, the western and southern populations have the larger pituitary glands than those in other sections of the country, perhaps due to racial differences man with a domi- nant anterior pitui- tary gland is likely to have a vigorous, commanding per- sonality, whereas the man with a dominant posterior pituitary may be somewhat effem- inate. That is by no means certain, but that some connection exists between balance of the glands and personality is undeni« able. The nervous system stimulates the glands, and the glands in turn stimulate the nervous system. The theory is growing that insanity itself may have its basis in the glands. Do you realize what this means? It means that behavior is controlled not only by the nervous system, but also by the blood stream. It means that your “‘nerv- ousness’”’ may not be wholly a matter of nerves, but partly a matter of your blood chemistry. And it may mean, some day, that a bit of this magic secretion mixed with your food or injected into your arm may change not only your physical ap- pearance, but your disposition as well. Conceivably, indeed, the salutation of the future may be, “How are your endo- crins today?” P a feo d month—The thyroid gland and its functions; how it is be- lieved to affect our physical and mental development. —

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our of ved, pre- n of inal olu- it is the od ay; ced ap- of do- be- tal ge” | Datwat4 year homes of the United States con- sume four thousand billion gallons of water. When you consider that practically every source is subject to pol- lution, the task of purifica- tion becomes vital. The pictures on this page are typical of improved meth- ods used in purifying the water you drink. In one of these processes, illustrated above, bags filled with cop- per sulphate crystals are pulled across the reservoir by a boat. The chemical de- stroys organisms that produce bad tastes and odors, espe- cially in the spring and fall TS 75 per cent of the population of the United States drinks water that has been sterilized by minute quan- tities of chlorine gas, 25 ounces of which often is sufficient to purify 8,000,000 pounds of polluted water. This form of treatment, while entirely harmless to the consumer, has been found the most effective destroyer of all disease-bearing germs, especially those of typhoid and dysentery. Above is a view of the chlorination plant at the Catskill aqueduct, N. Y., where gas from liquid chlorine is fed into _the water. The operator in charge is protected from chlorine fumes by a gas mask. At six other water-supply stations similar apparatus is used to insure against danger of water-borne diseases. Of the 525,000,000 gallons of water consumed daily in New York City, 85 per cent is surface water. Of this sur- face water, 99.8 per cent is sterilized by the very effective chlorine-gas process POPULAR SCIENCE MONTHLY How Science Purifies Your Drinking Water natural purification—the ae- ration plant at Kensico reservoir, Valhalla, N. Y., typical of a process that helps to safeguard your house- hold from disease. Here the reservoir water, hurled upward, is broken into very small particles. Thus partially atomized, the water releases many gases impart- ing taste or odor to the water and xi fe j ty WATER the presence of consider- able quantities of ammonia or nitro- gen, either as nitrites or nitrates, indi- cates sewage pollution. W.A. Horton, a New York City chemist, is shown above demonstrating how free am- monia is distilled from a measured quantity of water under examination SPECTACULAR form of absorbed during storage. At the same time, it takes up oxygen from the air, which in itself is an effec- tive disinfectant. Iron present in the water in solution changes form and goes into suspension, after which it is filtered out. Aeration further breaks up and retards the development of many vegetable organisms that other- wise might taint the drinking water A MUNICIPAL bacteriologist, counting the number of bacteria in a sample of water. In our large cities every precaution is taken thatno disease bacteria, especially those that develop within a short time at body temperature, are carried to water con- sumers. Small samples of water are placed in flat glass trays with culture jelly in which bacteria develop. These trays are incubated at various tem- peratures. If bacteria are present, they form in colonies that appear as spots. These colonies then are counted = i ta a oe the . ‘ ii _— Poe RE gh eee et ae ee eS i ae erncs oe pee eae

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ALOT hare ye rN ee re ata Reese aa bt 2 Sart raesiir Gia bX wae GRE FORA AE EE ape Beri SERINE ne se epee PAL Rae oe ee ae en i SRR TA POPULAR SCIENCE MONTHLY Laboratory Tests to Guide You in Selecting Radio and Tools Announcing The Popular Science Institute of Standards ITH this issue POPULAR SCIENCE MONTHLY in- augurates an extraordinary and, at the same time, the most useful service ever offered to the readers of a scientific magazine. Under the direc- tion of eminent engineers it has established THE POPULAR SCIENCE IN- STITUTE OF STANDARDS, a trustworthy and effective organization for the guidance and protection of readers in the purchase of tools, radio equipment, and other articles of a technical or semi-technical nature. The Institute of Standards has been created to determine by scien- tific test and inspection the efficiency and worth of mechanical and elec- trical products to the users, and thus furnish authoritative and impartial advice to prospective purchasers with regard to the products tested. It will be, in short, a safe and accurate index to reliably made mechanical articles. By using the service offered by the Institute, all readers of POPULAR SCIENCE MONTHLY, whether experi- enced in mechanical and electrical matters or not, will be able to make purchases of tools, radio apparatus, and similar equipment in full con- fidence that in their purchases they are receiving value for their money and obtaining honestly made goods of merit. The Institute of Standards, by making approved tests of mechanical and elec- trical products, performs the double service of pointing out articles that will give service and satisfaction and pro- tecting the readers of POPULAR SCIENCE MONTHLY from the possibility of selecting inferior articles. No service more useful and more necessary probably could be undertaken at the present time. If you have bought a radio set or radio parts recently, you probably do not need to be told how difficult it is for one who is not an expert to differentiate between high grade products and the inferior products that are manufactured to attract the inex- perienced radio enthusiast. CEILARLY, large quantities of in- ferior foreign tools have been un- loaded on the American market lately. These tools—automobile wrenches, for example—to the inexpert eye seem exactly like the high grade products of established manufacturers. Indeed, they are frank imitations of good tools—in everything but quality. Expert advice is the only protection that the ordinary man could have against purchasing these valueless articles, and it is in order that expert advice may be available for all its readers everywhere that PoPULAR SCIENCE MONTHLY has established the Institute of Standards. The Institute of Standards is under the active direction of Professor Collins P. The Director of THe PoPuLAR SCIENCE INSTITUTE OF STANDARDS—Professor Collins P. Bliss, Head of the Department of Me- chanical Engineering and Director of Testing Laboratories, New York University Bliss, Head of the Department of Me- chanical Engineering and Director of the Testing Laboratories at New York University. Dr. Hazen G. Tyler, As- sociate Professor of Mechanical Engineer- ing at New York University, is Associate Director of the Institute. There is available for THE POPULAR SCIENCE INSTITUTE OF STANDARDS staff, more than $300,000 worth of equipment and a fully organized staff of technical experts for the testing of radio apparatus, tools, and similar equipment. Organization of the Institute was effected the beginning of this year, and since then Professor Bliss, Doctor Tyler and their assistants have provided for definite tests and definite methods for separating reliable radio apparatus, tools, and other mechanical and_ electrical Subjecting a screwdriver to the torsion, or twisting test in the laboratory. The tool is load- ed with weights. From these is hung a container into which shot are poured gradu- ally while the in- creasing twisting of the steel is noted on a scale. It is by tests like this that the Institute can de- termine whether tools will give satisfactory service equipment from those of questionable worth. i? ORDER that readers may rec- ognize equipment that has been tested and approved, the Institute issues a seal and a certificate of ap- proval to the manufacturer of an article that has passed the tests. This entitles the manufacturer to display the insignia of the Institute as a token that his product has been ap- proved and is guaranteed to the readers of POPULAR SCIENCE MONTHLY as an article of sound quality, good workmanship and materials, one that will perform satisfactorily the work for which it has been designed, and that meets the claims made for it by the manufacturer in the columns of POPULAR SCIENCE MONTHLY. Under the guarantee of its seal, the Institute of Standards will adjust any possible dissatisfaction arising be- tween a purchaser and manufacturer because of the failure of an approved article to give satisfaction. Where a product approved by the Institute fails to give satisfactory service, the In- stitute will take up the matter of adjustment with the manufacturer, and if the manufacturer fails to adjust the matter satisfactorily, THE Popu- LAR SCIENCE INSTITUTE OF STANDARDS will either repair the article purchased or replace it with a perfect one. The Institute ‘guarantees without res- ervation that any approved product is good value, that it will justify the manu- facturer’s claims made for it in POPULAR SCIENCE MONTHLY, and that it will give > wwoomMmS toh an et & et 49 3. 09 Ps

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ist satisfaction under normal and proper use. Checks will be made on the original tests from time to time, and if articles manu- factured subsequent to approval prove to be of inferior quality to those first tested, the Institute’s approval will be revoked. The Institute’s tests are not conducted with any idea of determining the relative merits of various articles in the same class. If two radio sets, for example, sell for the same price, the Institute of Standards cannot un- dertake to express an POPULAR SCIENCE MONTHLY tools, it is necessary that the steel receive the proper heat treatment; also that it should havea certain hardness and temper. All these factors must be investigated and tested. Subsequently, a special test relating to the particular tool under in- vestigation must be devised and applied. While many of the existing types of test- ing machines are available for this purpose, it is necessary in many cases to perfect special machines that can be 35 tubes, tuning units, and other radio parts are similarly tested in actual use in re- ceiving broadcasting and by means of specially arranged laboratory tests. UP TO the present time, only tools and radio instruments have been under test. The scope of the Institute’s work, however, will be enlarged gradually to include the testing of automobile ac- cessories, paints, paint brushes, electrical apparatus, and many opinion as to which of the two is better. All that the Institute can say with regard to any article is that it is, or is not, of sound value and will, or will not, give satisfaction. In other words, the ap- proval of similar prod- ucts does not mean that they are neces- sarily of equal quality or merit, but that for the purposes for which the product is manu- factured and sold, as stated in the columns of POPULAR SCIENCE MONTHLY, it will give satisfaction when prop- erly used. PopuLaR SCIENCE INSTITUTE OF STAN- we DARDS. To the inexpert purchaser of a A SENSIBLE onl radio set, the sets pictured above would appear to be equal in quality. Yet, when subjected to tests by experts of the Institute, one of them showed marked deficiency in both selectivity and sensi- son does not ex- pect to get as much for five dollars as he can get for twenty-five. By the same token, the fact that the Institute may approve both a five-dollar article and one costing twenty-five dollars, does not mean that one article is as good as the other. Neither, for that matter, does it mean that one is any worse than the other. It does mean, however, that each article is worth the price asked, and will do satis- factorily the work it is designed to do. No service and guarantee of radio ap- paratus and tools on the comprehensive basis on which THE POPULAR SCIENCE INSTITUTE OF STANDARDS is conducted ever before has been offered to the readers of a magazine. Radio sets, tools, and other mechanical appliances differ so widely: that very different tests are required to demonstrate the value in each case; but in one respect all tests conducted by the Institute of Standards are similar—every article is given both a laboratory test and a practical test of actual use. In many cases, also, inspection of manu- facturing methods at the factory where a tool, for example, is made is helpful in determining quality, and such inspections are made by the directors of the Institute. Every possible effort is made to determine absolutely that products offered to readers of POPULAR SCIENCE MONTHLY are of good quality. THE quality of a tool, of course, de- pends largely on the quality of steel. from which it is made. Hence, one of the first necessities in establishing its grade is to determine the physical properties of the materials used in its manufacture.. Then, in making certain applied to the particular tool under test. The complete plan of tests worked out by the Director of the Institute involves not only the use of well equipped labora- tories and machine shops, but also the checking of all tests made by manu- facturers where these are of value in de- termining the merit of any product. FTER the technical tests and in- vestigations are concluded, the tool is put to practical use to determine what difficulties, if any, the average users may experience with it. Since the prime purpose of the In- stitute is practical—to determine for the readers of POPULAR SCIENCE MONTHLY whether tools and mechanical instru- ments will do the work they are supposed to do—the new apparatus being developed for laboratory tests likewise is practical. It is designed solely to inform the man who wants tools or mechanical instru- ments what tools and instruments will give him satisfaction. For radio sets, the tests are designed to gage electrical efficiency, selectivity, sensitivity, and mechanical construction. Besides being tested by the reception of ordinary broadcasting, the sets also are tried out in conjunction with a miniature transmitting station erected in the laboratory, which permits the tester to vary the strength of the signals to be received. Loudspeakers and headphones are tested for tonal quality and distortion, not only in actual use with a radio re- ceiving set, but also by means of special sound-producing apparatus. Vacuum other kinds of mer- chandise. It should be under- stood that although the Institute of Stan- dards is financed and maintained by Popvu- LAR SCIENCE MONTHLY, it functions as a separate, independent organization. Its stan- dards will be determin- ed, its tests arranged and conducted, and its decisions made entirely by its directors and their laboratory staff. The Institute will ap- prove or disapprove an article only on a basis of facts revealed by scientific and practical In the radio testing laboratory of the tivity. In other words, it was not tests. worth the price asked for it. The other was found to meet every claim of the manufacturer, and so has received a certificate and seal of approval from the Institute — a guarantee to POPULAR ScrENCE MONTHLY readers that the receiving set will perform satisfactorily THE POPULAR SCIENCE INSTITUTE OF STANDARDS is first and last a service for the readers of POPULAR SCIENCE MONTHLY. Its aim is to safeguard them in their purchases of mechanical equipment, and in order that the In- stitute may function with greatest effi- ciency and widest usefulness, readers of this magazine, in making purchases, are urged to make full use of its service. By looking for THE PoPpuULAR SCIENCE INSTITUTE OF STANDARDS’ insignia, in- dicating approval, you can protect your- The seal of approval of THE PoPpuLAR ScrENCE INSTITUTE OF STANDARDS. A list of the radio and tool products that have received this seal will be sent to you by the Institute on request selves with the Institute’s guarantee. Advice will be given freely, and may be accepted with confidence. POPULAR SCIENCE MONTHLY will be glad to furnish, upon request, a list of products tested and approved by THE PopuLAR SCIENCE INSTITUTE OF STANDARDS. m4 7) ban eS ee a in a = ae ~ oan Poneeieeet tee * ee — ee

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H 'e i 36 POPULAR SCIENCE MONTHLY Driving the Store to Your Door Novel *‘Taxi Grocery’? Combines Unusual Service with Economy By Lynn B. Dudley ELLING foodstuffs from S door to door—carrying the store to the cus- tomer—is not a particularly new idea in itself. The wagon of the food peddler is a feature of life in the towns and cities of this country that antedates the memories of the oldest of us. But it has remained fora concern in Detroit, Mich., to make use of the idea on a really large and useful scale by equipping a big motor van as a store on wheels capable of supplying families within a radius of 35 or 40 blocks with a complete stock of groceries, breads and cakes, fruits, green and staple vegetables, meats and drug sundries. This novel motorized store is said to combine the desir- able features of the “‘cash and carry” chain stores and of the higher price stores that de- liver goods on phone order, without possessing the disadvantages of either. Thus, while the low prices of the chain store prevail, the busy housewife is enabled to do her own marketing without loss of time and without the inconvenience of carrying heavy packages a distance of several blocks. HE “‘taxi grocery”’ is able to maintain these low prices while giving extraor- dinary delivery service, for several rea- sons. First, its upkeep is negligible com- pared with the overhead cost of operating an ordinary store. It has only one clerk, who also is the driver and cashier. Rent, light, heat, window displays, and other expense items that add heavily to the cost of conducting the usual store, and which, of course, are borne by the customer, virtually are eliminated. Then, instead of drawing an indifferent trade from a radius of from three to five blocks, the traveling store covers an area of several square miles, and supplies a correspondingly large list of customers Interior view of the new Detroit “taxi grocery,’ looking toward the rear. The goods are handily arranged on both sides, so that customers can help themselves. An ingenious overhead carrier system supplies a basket to each¥customer. In the fore- ground is a combined refrigerator-counter regularly. The result is that, whereas the receipts of the average chain store are less than $500 a week, those of the motor store are reported to be averaging well over $1000. Further, the increased number of customers over those of the average store has resulted in a turnover of stock un- heard of in the grocery or meat trade. The turnover of the usual chain store is 13 times a year. That of the store on wheels is 100 times. The floor space in the motorized store is 22 feet by 714 feet. Ingenious arrange- ment of the commodities on shelves and in bins, each marked with its own price tag, permits 10 or more persons to wait on themselves at once without crowding. A large basket conveyed by an overhead carrier is supplied to the cus- tomer when she enters. Into this she places the goods she desires to purchase as she makes the round of the store; then the goods are checked and wrapped by the driver as she departs. Cold meats for immediate use are carried as ordinary stock, but orders are taken for all kinds of meat, and de- liveries are made on the fol- lowing day. The car has only one show window—in the rear. In this vegetables and fruits are displayed. Potatoes and similar bulk vegetables are sacked in varying quanti- ties all ready for the cus- tomers. AN INGENIOUS system of hot-water heating from a central plant in the cooling system of the motor, keeps the traveling store warm during cold weather. Ventilators remove the odors of burning gasoline and oil. The first taxi grocery was put in service by the Wright & Parker Co., of Detroit, as an experiment. The idea has proved so successful that a fleet of similar cars has been ordered, and a warehouse and garage are being built to develop the motorized grocery service on a large scale. Improvements suggested by the trial of the first moving store will be incorporated in those that are to follow, and it is con- templated extending the range of service widely. The plans include the addition of a laundry service and a banking system, as well as to take orders for coal and pos-. sibly other similar commodities for deliv-. ery on the following day. , Shouid these additional features prove successful, it is not impossible that this unique system of household service even- tually may revolutionize the present-day system of distributing food and other household necessities, incidentally reduc- ing the cost of living. By bringing household necessities to your door, this novel “store on wheels” offers to the housewife the convenience of a delivery system plus the advantage of “cash and carry” prices, It serves a wide territory The rear of the motorized store is almost entirely of plate glass, forming an attractive display window for fruits and vegetables. The goods are well displayed on three shelves

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) y ie cus- - Into ds she is she store; 1ecked driver ediate dinary taken nd de- he fol- is only n the es and ytatoes otables juanti- e cus- system eating in the motor, store eather. > odors service etroit, ved so irs has garage torized trial of vorated is con- service n of a em, as id pos-_ - deliv- , prove at this > even- nt-day other reduc- t POPULAR SCIENCE MONTHLY 37 A Poor Man’s $250,000 By W. D. Thomson OME time in the spring of sy 1925 there will be opened at Ohio Wesleyan Uni- versity, Delaware, Ohio, an astronomical observatory that will house the third largest telescope in the world. In itself that is a remarkable fact, for Ohio Wesleyan is a relatively small college, having less than 2000 students. Even more remarkable is the fact that the telescope, unlike other great astronomical instruments, is not to be used for research by learned scientists exclusively. On the contrary, its donor specified that it must serve, first the students of the university, then the general public, and re- search last of all. But the most. amazing feature of all is the circumstances under which the college comes into possession of its gift; for the telescope and observatory rep- resent the achievement of one man’s purpose, won at the cost of almost unbelievable self- sacrifice, perseverance, modesty, and steadfast devotion to the cause of science. The telescope and observatory are the gift of the late Hiram Mills Perkins, for 50 years a Laid to The 60-inch reflecting telescope—third largest in the world—given to Ohio Wesleyan University by the late Prof. Hiram Mills Perkins (inset), who purchased it with the savings of a lifetime the new Ohio Wesleyan observatory. At his left is Dr. C. C. Crump, director of the Perkins observatory, and at his right, President John W. Hoffman of Ohio Science ; he had shared his secret am- f-=| bition, did not change their . modest scale of living. Professor Perkins never cashed the divi- dend checks from the enterprises in which he invested his money, but reinvested the return in securities; for each new oppor- tunity of earning brought him closer to the achievement of his ambition. His sister and his brother - in - law contributed $75,000 to the telescope fund; otherwise the money came en- tirely from him. Only once did he and Mrs. Perkins relax from their rigid economy. That was when they took a trip around the world following the pro- fessor’s retirement. ROFESSOR PERKINS lived to fulfil his ideal, for it was he who broke ground for the observatory, while his wife, who died six months later, proudly watched the consummation of the purpose to which they had dedicated their lives. Unusual mechanical features of the Perkins telescope will make it even more remarkable than the two instruments that surpass it in size—the 100-inch telescope at Mount Wilson, Calif., and the 72-inch telescope at Victoria, B. C. It has a many times more than the total amount of money Professor Perkins received from the university during his half century of service. The highest salary he ever re- ceived was $1800 a year, and that for only a few years prior to his voluntary resig- nation as_ professor of mathematics and astronomy in 1907. The money for the ob- 1 Vee, —_ +@y rat mY ip “ ~ as servatory was derived from a series of in- vestments extending through 50 = years Wesleyan University, during the impressive ceremony and carefully hus- banded and reinvested member of the faculty of the university, with the sole purpose of buying the who died a few months ago at the age __ telescope. of 90—a poor man. He was poor from choice, because dur- ing his long life he had amassed a fortune of close to a quarter of a million dollars. Every cent that was his, though, went to purchase the telescope and observatory. To give Ohio Wesleyan modern astronom- ical instruments and to bring astronomy within reach of the masses were the objects to which he had dedicated his life. The cost of the gift—$250,000—was And when the time arrived that Pro- fessor Perkins was able to turn over to the university an amount sufficient to serve as the nucleus of a building fund, he tried to keep secret the fact that the money came from him, compelling B. E. Cartmell, treasurer of the university, to carry the account on his books as a donation from “Mr. X.” All the while that his small fortune was growing, he and his wife, with whom The 460-ton pier on which the great telescope will rest. The telescope itself will weigh 37 tons, but will be so delicately balanced that it can be operated by one man. Built in Cleveland, it is ready for installation in the observatory, which will be completed for use next spring 61-inch lens, and weighs 37 tons, but it is balanced so delicately that when moving with the earth’s rotation to keep an observer’s vision focused steadily on a star, it uses no more electric current than a household electric light. Thirty motors are required to adjust the Victoria telescope. The Perkins in- strument has but seven, and can be op- erated by one man. New safety. ap- pliances. cause the instrument to stop moving instantly should the operator lose control of it. i f FF f | | | Ties ST ae — —~ re & i at [ | i :

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38 POPULAR SCIENCE MONTHLY New Discoveries in Science The Top of the Air—Spring Fever—Radio— Automobiles—Health AN devotes a lot of atten- M tion to the air these days. Now that radio concerts are drifting through the air for 24 hours a day and modern Magellans are using the air to circumnavigate the globe in flying machines, the air has achieved an importance never accorded to it in the days when it was employed almost exclusively for breathing purposes. And in view of the new fame it has achieved, it is a coincidence that science has discovered that ap- parently more air surrounds the earth than ever has been suspected. A few weeks ago the Abbé Moreaux, noted French astronomer, announced that scientific tests seemed to indicate that the atmos- phere extended about 540 miles beyond the earth’s surface. This is more than five times as far as science previously had estimated the atmosphere’s height. Of course, the atmosphere in its upper regions scarcely resembles the air we breathe. Up to about 10 miles, according to the Abbé Moreaux, is found the air we know, composed mostly of oxygen, nitro- gen, carbonic acid, and a few rare gases with the supply of oxygen diminishing, as aviators and mountain-climbers have taught us. Beyond the 10-mile point, to a height of about 60 miles, nitrogen is the predomi- nating constituent of the atmospheric envelope. This region has no storms nor winds. This statement supports the recent discovery of a nitrogen layer beyond the atmosphere by Professor Vegard, of Nor- way. Above this layer, extending to 100 miles or more, is another layer, mostly hydrogen, according to the French as- tronomer. At this point science always had believed the atmosphere ended. But, according to the Abbé Moreaux, still an- other dense layer of unknown composi- tion stretches more than 400 miles. The apparent existence of this un- known atmospheric stratum was de- termined by ingenious observation of the aurora borealis. Simultaneous exposure On the theory that fatigue is a bodily poison for which there should be a definite remedy, Dr. Fred B. Flinn, of the United States Public Health Service, is study- ing the effects of in- dustrial labor on the hu- man mechanism. He is shown above in _ his laboratory investigating the effect of sodium-di- hydrogen phosphate in delaying fatigue. A Ger- man physiologist claims to have administered this salt to shock troops during the world war, with the result that they were less tired than usual at the end of a battle bury, reporting the re- sults of an investigation into the relation between climate and physical ef- In the late ful here and because the gas-driven engine has been developed to such efficiency. In other countries, though, gasoline is obtained neither so cheaply nor so conveniently, and this explains the activity of foreign engineers in experimenting with other motor-car fuels. In Sweden, for example, a native-built car run by alcohol is said to have given remarkable per- formances. The gasoline used in Sweden comes from America, and is expensive. In addition, virtually all cars there are imported. There- fore the alcohol-propelled vehicle naturally aroused much interest among those who before had been unable to afford a car. Government restrictions prob- ably will impede for a time the growth of the motor industry in Sweden, for prohibition there has placed the manufacture and dis- tribution of potable alcohol under strict control. However, one solu- — By means of an instrument known as a millivolt meter, shown i ie i oe ee ee ee a ee ficiency. y above, Dr. I. F. Hand of the U. S. Bureau of Agriculture, has succeeded in recording and measuring the heat radiated by the sun. Doctor Hand estimates the amount of heat from the sun of more than 600 photographs from dif- spring and early summer, ferent points and subsequent trigonom- Doctor Norbury asserts, 44 4 a f Fy i i 4 ih Np a ac etric calculation indicated that the aurora extended its electrical manifesta- tions 540 miles above the earth. It was assumed that these phenomena could not display themselves in empty space, and it was concluded in consequence that there must be some sort of atmosphere 540 miles or more away. Science and ‘‘Spring Fever’’ bin is the time of year when you should be able to do your best work. Strangely enough, though, this also is the time of the year when you are most likely to have a mental breakdown. These paradoxical statements were made to the American. Meteorological Society recently by Dr. Frank P. Nor- man is stimulated into activity, and conse- quently works best. Under the prod- ding of his new-found energy, he is likely to work so hard, though, that he’ll be- come exhausted. Then, if he has a natural tendency to mental disorders, collapse will come. Man is more closely dependent on nature, and particularly on the weather than he ever has realized, declares Doctor Norbury. New Gasoline Substitutes ie WILL be a long time, American automotive engineers assert, before automobiles in the United States will employ generally any fuel besides gaso- line. This is because gasoline is so plenti- in midsummer to be about one horsepower a square meter tion of the problem is offered through the development by German chemists of a method of producing wood alcohal by the chemical combination of carbon monox- id and hydrogen. This revolutionary process is said to be capable of providing wood alcohol in quantities for little cost. Meanwhile French automobile indus- tries, through the use of gas generators, generally are replacing gasoline as a source of power in agricultural motors, such as tractors and plows. These gener- ators, which burn coal, coke, or charcoal with equal success, also have been used on automobiles. It is entirely possible that as a result. of these experiments there may be developed a new type of auto.

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Cy th ven uch ‘ies, cher and ign vith l is per- | in and ally ere- ‘icle rest een rob- the Y in has dis- der olu- Nitrogen Tube for Radio Wee experimenting with a two- element nitrogen-filled tube in the physics laboratory of the University of Pennsylvania recently, in an endeavor to determine the number of electrons in an atom of nitrogen, it occurred to Dr. E. E. Witmer and Professor Charles B. Bazzoni that the tube might be em- ployed to pick up radio signals. The addition of a transformer and a head- phone brought in perfectly the pro- grams broadcast from a local station. No ground connection, aerial or tuning apparatus was used. This ex- periment was undertaken without the idea of contributing any new principle to radio reception, yet it offers decid- edly interesting possibilities. A Cure for Pyorrhea ROM the University of Toronto, which gave the remarkable serum insulin to the world a year or so ago, came an announcement recently of an- other amazing discovery in medical science—a cure for pyorrhea, the sup- posedly incurable disease of the teeth and gums from which, physicians tell us, half the people in the world suffer. Like Doctor Banting, discoverer of insulin, Dr. Harold Box, who is re- sponsible for this new gift to science, is a young and hitherto obscure research worker. According to the announce- ment made by the university, Doctor Box has discovered that pyorrhea is not caused by infection, but by de- generation of tissues, and after five years’ work, has found a means of arrest- ing this action. Pyorrhea causes the gums to become painfully inflamed and to re- cede from the teeth, which eventually become loose. Hitherto, dentists believed there was no way of coping One of the world’s most extraordinary artists is Prof. L. H. Wilder of the United States Public Health Service. He is a painter of insects, bacteria, parasites, and countless living POPULAR SCIENCE MONTHLY with the disease except by extracting the teeth. Like insulin, Doctor Box’s method of treatment has been turned over to the Government without restrictions, to be made available to the public. A view of part of the apparatus used by Professor McAdie in weighing human breath. The weight is recorded in kilograms to the cubic meter of space on the chart shown at the right The dangerous task of finding a serum to com- bat the dreaded Rocky Mountain spotted fever, carried by the little wood tick found on animals of the Montana mountains, has been undertaken by Dr. R. R. Spencer of the Hygienic Laboratories, Washington, D. C. Doc- tor Spencer is shown above seated at his microscope, while his as- sistant, L. H. King, is seen examining the blood of a guinea pig inocu- lated with the fever germ. Several experi- menters already have given their lives in the fight against this con- tagious fever, which is accompanied by erup- tions of small red spots, usually abundant over organisms so small as to be invisible to the unaided eye. The the trunk and limbs purpose of his work, accomplished with the aid of powerful : microscopes, is to aid science in man’s fight against carriers of disease. Professor Wilder is shown above completing, in true color, a painting of the common stable fly, which is said to be a carrier of infantile paralysis and other dangerous diseases 39 Paint as a Disinfectant PAINT now is being hailed as an effec- tive germicide and disinfectant. The Institute of Industrial Research in Washington, D. C., demonstrated by actual test recently that germs cannot find ‘lodgment on a freshly painted wall, since the paint closes up the pores of the material and prevents it from absorbing the moisture necessary to germ growth. The New York City Health Depart- ment has begun the practice of paint- ing, rather than fumigating, the rooms occupied by sufferers from contagious diseases. From a maternity hospital Prof. Alexander George McAdie of Harvard University is pictured above breathing into a delicate apparatus with which he has succeeded in measur- ing the weight of human breath. This instrument, known as the psychrometer, or chill measurer, somewhat resembles a thermometer, barometer, and scale. It weighs the vapor exhaled in breathing. In recent tests the breath of 200 students was found to weigh 360 pounds in Chicago has come an even more surprising story of the value of paint in combatting disease. A short time ago this institution har- bored more than a hundred cases of puerperal fever. Then the hospital was painted, inside and out, and the puerperal fever virtually disappeared. More and more modern science is of the opinion that the most efficient health weapons are commonsense and cleanliness, 10,570 Miles by Radio ERE’S a new DX record in radio: The British steamer Port Kemble reported to the United States Hydro- graphic Office recently that her radio equipment picked up the Washington, D. C., time signals while she was between Cape Town and Australia in approxi- mately 46° south latitude and 95 degrees east longitude. That made her 10,570 miles away from the source of the signals, That’s just about as far away as one object on the earth can get from another. A Car that Runs Sideways MOTOR-CAR that can go forward, backward, and sideways to the right or left with equal facility recently caused quite a sensation in London. This queer vehicle also can leap a ditch, climb the highest curbstone without jar, and turn completely around in twice its own length. The car derives its unusual abilities from the fact that each wheel is inde- pendent of the other. , bi & M4 i i ‘Ae fi ee aw ee pete Sh SEER SEITE ELT I ae ee ae

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40 World Fliers Ready for Any Emergency By Corley P. McDarment POPULAR SCIENCE MONTHLY

One of the four Army world cruiser air- planes, showing pontoon equipment for emergency landings during sea flights are built high out of the water and the pontoons are tested to withstand ordinary gales and seas. A mechanic probably can make minor motor repairs on the ocean with the seas running. HE most thrilling airplane wreck at sea, excepting the mishap of Hawker and Grieve, in their attempt to cross the Atlantic early in 1919, was the Macmillan and Malins disaster in the Bay of Bengal in August, 1922, during the famous Major Blake expedition which started from England to fly around the world. Three times when they were brought down by motor trouble, they were able to make repairs and to take off from the water.

The contents of one of the airplane toolkits for the flight around the world, now in progress of the Pacific, skimming over the endless deserts of Persia, or the jungles of India, or coming down with motor trouble among the floes of summer ice off the coast of Greenland, the United States Army aviators who are flying around the world in four specially de- signed planes have at least one substantial source of comfort for any emergency— that is a fully equipped toolkit. When the great world flight was planned, the matter of a proper toolkit was considered carefully, with the result that the kit carried by the modern Magellans is one of the most complete and compact ever assembled. Packed in a cloth container measuring 17 4 by 16 by six inches, are nearly all the necessities for repairing plane or motor. It is amazing how much can be placed in so little space. Besides wrenches, files, screwdrivers, safety wire, turnbuckles and extra spark plugs, are accessories like thermos bottles, collapsible water bucket, block and tackle, field glasses, paint brushes, hand ax, blowtorch, signal pistol, quart measure for oil, soldering iron, manifold connections, and copper tubing. The crossing of the Atlantic and Pacific oceans presents the greatest difficulties of the flight. And the chance of forced repair work in midocean offers the most thrilling possibilities. It will be remembered that Commander Towers of the United States Navy, during the transatlantic flight in 1919, was forced down near the Azores. After a remarkabie repair job, he pulled into port on his own motor power, but ‘“‘taxi-ing” on the water, since the waves prevented taking off again. The four Army world cruiser airplanes Ser the 3 out over the long stretches

But the fourth time they were unable to get off. The rains began, water soaked the wings and fuselage, and the sea and wind rose. The plane was overturned and sank slowly for four days, while the desperate airmen clung to the pontoons. Finally, they were picked up by a launch just in time to save their lives. This was the first striking instance of an attempt by aviators to perform diffi- cult repair work at sea. One of the objects of the present flight around the world is to study the problem of supply incident to long flights. In this connection the importance of the toolkit is obvious. When the flight is completed, many recommendations undoubtedly will be made as to the most useful tools and equipment for an extended air journey. The tools are carried in this compact bag, measuring only 1714 by 16 by six inches oe GRAVITY GASOLINE 5-GAL EMERGENCY ,,SUPPL WATER TANKS FOR — eT INE LIGHTS RADIATOR ———— 3 400-H.P 54 NSTRUMENT : Ae MOTOR —— 3 BO ARD == i ay ‘ae | \ edie I PARACHUTE OUTFIT = yN LD SMALLER COMPARTME! mew ee Va

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TAIL OIL TANK SKID 30 GAL. AP?

GAS TANKS Lm “Od LANDING WHEEL EQUIPMENT FOR LAND FLIGHTS The special design and equipment of the driven pump (B), or by a hand-operated United States Army world-cruising airplanes pump (C), in the_rear cockpit. In case all of are shown above. One of the most remark- these three systems should fail, there is a 60- able of the safety provisions consists of three gallon emergency gravity supply of gasoline distinct gasoline systems. Gasoline from ina tank located in the upper wing. The total tank 1, 2, or 3 is pumped to the carburetors, gasoline capacity of the airplane is 450 gallons either by a wind-driven pump (A), an engine- —enough for an 18-hour non-stop flight WIND=DRIVEN EARTH INDUCTOR COMPASS

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POPULAR SCIENCE MONTHLY

41 Nature’s Magic in Radium The Modern Philosopher’s Stone and Its Wonder Secrets

Laboratory apparatus used in capturing and condens- Md

ing radium emanations for the treatment of disease y he o me / In our April issue, Raymond J. Brown presented to POPULAR SCIENCE MONTHLY readers a delightfully graphic picture of the world of the infinitely small —the amazing world of atoms and electrons. In the same lucid, simple language he tells, this month, of the magic world of actuality—of Nature’s wonder el- ement, radium. Readers will watch with interest for a third article that Mr. Brown is pre- paring for the July issue, pictur- ing the wonders of the heavens— the world of the infinitely large. By Raymond J. Brown HERE was a break in the radium market not long ago. The price suddenly plunged from $3,300,000 an ounce to $2,500,000, due to the dis- covery in Katanga in the Belgian Kongo of extraordinary deposits of a radium- ~ bearing ore, from 25 to 30 times richer than the earth ever before yielded. Even more recently new fields of unusual promise came to light in some old copper mines in. Czecho-Slovakia, a circum- stance that may drive the market price down still further, though not to such an extent as 25 per cent. These statements are likely to be misleading, for the standards and values by which we measure other things simply do not apply to radium, the wonder element. When you hear of the market price of radium being $2,500,000 an ounce, you immediately get the im- pression that if Henry Ford, say, desired to possess himself of a couple of pounds of radium, it would be necessary for him merely to put his checkbook in his Apparatus used to transport ore containing uranium, from which radium is obtained - pocket, fare forth to the radium marketplace, and carry the stuff back with him in a satchel. I OW, as a matter of fact, Mr. Fordcouldn’t buy a couple of pounds of radium. He couldn’t do it if he had the Rocke- feller and the Mellon for- tunes and the output of the United States Mint to back his own resources. He couldn’t do it for the simple reason that there aren’t a couple of pounds of radium on earth. In the 26 years since radium was discovered, man has been able to store up less than a quarter of a pound of the precious stuff. Those who have radium and need it — research scientists and physicians —would not part with

their little stores at any price. Besides, radium is not sold by the ounce, any more than gold—which is more than 100,000 times less valuable—is sold by the ton. When radium does change ownership, it does so in fractions of a gram, and a gram is about one-thirtieth of an ounce. The largest consignment of radium ever moved consisted of only two grams, and that was not sold. It was merely lent to England by the government of Czecho-Slovakia for scien- tific research. NO is the discovery of a rich mine in the Belgian Kongo likely to make radium appreciably more plentiful. The ore taken from the new African mine contains merely from 25 to 30 times more of a source of radium than is found in the usual radium mine. Extracting the radium from this source is a lengthy, costly process. In fact, 500 tons of the first rock mined yields only a gram of radium in combination with barium and chlorin. And even this is accomplished only after the employment of 500 tons of chemicals, 1000 tons of coal, 10,000 tons of distilled water, and the labor of 150 men for a month! Moreover, extract- ing the pure radium requires five weeks’ work by a corps of expert chemists, and four months more elapse before that single gram of radium is ready for use. Think of it—six months’ work to produce a bit of radium that would rattle around loose in the barrel of a fountain pen! One part by weight of radium ex- tracted from 50,000,000 parts of ore after a half year of effort! A long, long time will pass before this new source of radium in the Kongo develops the half ounce necessary to bring the world’s supply up to an even quarter pound! Now, its rarity and value, though ex- ‘ ceeding those of any other substance, are _ by no means the most amazing features

A diagrammatic representation of the sun’s corona, that hurls tongues of fire thousands of miles into space, and that may spring from immense quantities of radium within i po Cap ates ne ee 8 Ee

PONE EOE FRI

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A Sef EEO IPN EYE IE NTN I OR LE TOT TN Pe TS HTT RYN RE OTE LNAI PLN EL I oenan SS eae RES a Pont es "et oS ti > di ROG 42 of radium. It is the one substance re- garding which the most matter-of-fact scientist does not hesitate to utter super- latives, frame surprising theories, and permit his fancy to run free. SK the chemist about radium, and, after he had salved his scientific conscience by telling you it’s a metallic element like iron, or copper, or zinc, and POPULAR SCIENCE MONTHLY Interior view of a lead vault in which the Radium Emanation Cor- poration of New York City stores radium for the manufacture of “radium seeds’’—the tiny capillary tubes containing radium emana- tions that are supplied to physicians for the treatment of disease. Two grams of radium bromide is kept in a flask in the chrome nickel safe shown in the center. that it’s one of the heaviest substances known (also true of lead), he’ll probably go on and call it the supreme marvel of Nature’s storehouse. He’ll also tell you that it is the Philosopher’s Stone, which the alchemists of old searched for as the agent that would effect the transmuta- tion of the base metals into gold. And he will back up these surprising state- ments by scientific fact, as we shall see presently. SK the physician about radium, and he will tell you that it gives every indication of proving the most remark- able remedy ever given into the hands of science, and he will name the wide variety of uses to which medicine already has put it. Ask the physicist, and he will call it the most marvelous tool ever placed in his laboratory. He will tell you how its strange properties enabled him to frame Within this safe are cooling coils to maintain constant temperatures, and the safe is lined with swans- down. Emanations from the flask pass through glass piping at the left to the exterior of the vault, pictured on the opposite page the amazing new theory of atomic structure that threatens to revolutionize all work in the natural sciences. Ask the geologist, and he will tell you that radium offers a plausible, tenable explanation of volcanic action and the mysterious heat of the interior of the earth. Ask the astronomer, and he will all but prove for you that radium is the source of the light - . and heat of the A} sun and stars, the _ secret of their seem- - ingly eternal en- ergy. Ask the biolo- gist, and he will go even further, asserting that radium may be the fountainhead from which sprang all life. Ask the engineer, and he will tell you that, with suf- ficient radium at his command, he could develop power in unheard- of quantities and devise machines capable of perform- ing work under which the mighti- est machines of today would crumble! Meanwhile industry utilizes its share of the pittance of available radium in the manufacture of *the paints that illuminate watch hands, electric switches, compasses, and airplane instruments at night, and in making gems. Exposed for a short time to the action of radium, the colorless crystals of corundum (white sapphires) for example, turn permanently into blue sapphires—not imitations, but the actual stones themselves. Now, what is the amazing property of radium that makes it so exceedingly useful? The answer is—radio-activity. Radio-activity means just what its name implies—activity in the form of rays. In a scientific sense, though, spontaneous action is meant. The discovery of this phenomenon in 1895 by Henri Becquerel, famous French scientist, paved the way to the discovery of radium. Investigating phosphores cence, Becquerel noted that substances containing the element uranium affected a photographic plate in the dark, even when the plate was protected by black paper. And so 30 years ago the scientific world accepted as a new and startling fact the radio-activity of uranium, par- ticularly as exemplified by its oxid— pitchblende, a pitchy, black mass found at Joachimsthal, between Bohemia and Saxony, and used for years in coloring glassware and porcelain. ROME time later a young Polish woman studying chemistry in Paris became interested in this mysterious property of uranium. She obtained some pitch- blende from the Joachimsthal deposits and began experimenting with it. She quickly came to the conclusion that the radio-active substance was not uranium, but some other constituent of the pitch- blende. Reducing her sample of ore by washings, treatment with acids and similar methods, she noted that the radio-activity of the residue steadily increased. At last, from several tons of ore she obtained three ounces of a_ substance 60 times stronger than uranium by electroscopic test. This substance ap- parently had the properties of a chemical element, and the young experimenter an- nounced her discovery, naming it po- lonium, in honor of her native land. Steaming distilling vats in a radium refining plant at Pittsburgh, Pa. Ten thousand tons of distilled water are used in washing a single gram of radium from 500 tons of ore. In addition, 1000 tons of coal and 500 tons of various chemicals are required to obtain this one gram (about one-thirtieth of an ounce) of the wonder element a Further research, however, showed that the discovery of polonium was merely a step in the quest of the radio- active element, and after three years Madame Curie, for that was the name of the experimenter, announced that at last she had isolated the source of the radio-activity of pitchblende. Thus was the wonder element radium given to the world. RADUALLY science learned more about radium. Sir Ernest Ruther- ford in England discovered that its rays were of three kinds, and he used the first three letters of the Greek alphabet to distinguish them, calling them alpha, beta and gamma rays. Alpha rays_were found to be positive charges of electricity, moving at a rate of 20,000 miles a second, about 40,000 times faster than a cannon ball. These have small power of penetration and can

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\OTeg~ ances ected even black ntifie tling par- xid— ound _ and oring oman came ty of vitch- 0sits She t the ium, vitch- re by and , the adily e she tance 1 by e ap- mical or an- t po- owed was ‘adio- years name at at f the 3 was o the more ither- rays 1 the habet pha, sitive , rate 0,000 These d can POPULAR SCIENCE MONTHLY pe $2,500,000 WOULD BUY IN | RADIUM-DIAMONDS-PLATINUM AND GOLD GOLD_3°%4TONS PLATINUM 3% TON eee nee Ne Aen Oe SR Ne RN: I cc NOR eR NN eR nes sone ce Ai sein ei i at The tremendous value of radium as compared with diamonds, platinum, and gold. In the 26 years since radium was dis- covered, man has been able to store up less than a quarter of a pound of the wonder element. be stopped by a paper-thin sheet of glass. The beta rays were demonstrated to have a_ velocity ten times greater; virtually the same as that of light. These were found capable of penetrating the skin to a depth of half an inch and of passing through thin sheets of glass or aluminum, or a lead plate one-twelfth of an inch thick. HE gamma rays were almost identical with X-rays, but of shorter wave length. These have the greatest pene- trating power, finding their way through 10 inches of lead. But an even more remarkable dis- covery was that the alpha rays, after their emanation, collected in some mys- . |i tom * PTL : i: : nn oat Sie SL eh, Examining samples of radium-bearing ore in the laboratory of the United States Bureau of Mines at Denver, Colo.” terious manner two negative charges of electricity, or electrons, and became atoms of helium! In other words, radium was steadily giving off another substance, as widely different from radium in chemical characteristics as any two substances could be! And from this mysterious casting off of helium atoms by an element that contains no helium, science has arrived at some of its most startling conclusions. It has formed the theory, for example, that all matter in the universe is electricity. It Owing to its extreme scarcity, it is more than 100,000 times as valuable as gold has found a believable solution of one of the most profound mys- teries of the universe— the source of the sun’s light, heat, and energy. Helium was discovered in the sun long before it was found on earth. The spectroscope dem- onstrates that there are huge quantities of he- lium in the sun’s corona, the flaming halo that surrounds it and hurls its tongues of fire thou- sands of miles into space. Does not the presence of helium in this fiery ring argue the presence of radium in huge quan- tities in the sun’s in- terior? Further, is it ‘unreasonable to suppose that all the light and heat of the sun spring from the terrific energy unleashed as countless tons of radium hurl into space their storm of radio-active beams? A single gram of radium gives off enough heat to melt its own weight in ice in three-quarters of an hour. If the sun, which is 100 times larger than our globe, were composed in large part of radium, would not that ex- plain its terrific heat? Science knows that the sun’s heat is not due to com- bustion. Radium, too, emits heat without rapid com- bustion. Also, the penetrating gam- ma rays of radium partake of the gen- eral nature of light waves. If billions of those rays were constantly shoot- ing into space from the sun, might they not in the 93,090,000 miles they must travel 43 to reach us, arrange themselves into the form of the light waves we know? This hypothesis supplies more than an op- portunity for interesting speculation. A similar process of reasoning supplies plausible explanation of the heat of the plastic materials that lie beneath the earth’s thin crust, of volcanic action, boiling springs and geysers, and similar natural wonders regarding whose causes scientists long have wondered. Sacer radium gives forth energy and generates heat without ap- parent loss of substance, it really is suffering a change. But the change is so slight as to be almost negligible. In the matter of heat, for instance, a gram of radium in a year gives off 1,160,000 calories—enough heat to boil 25 pounds of freezing cold water. In the process, though, the radium loses only 1/2500 of its weight. In giving forth its rays, radium also alters its substance. From the rarest element known it transforms itself into a substance that long has served as a symbol of cheapness—lead. The trans- formation, though, requires 3460 years, so that radium hidden in the earth more - than 1500 years before the Christian era has not yet become lead. To the scientist, this is the most (Continued on page 129) WN Exterior of the lead vault for storing radium. The radium emanations piped from within continue to pass through piping that contains coils to remove water vapor and purify. At last the emanations reach a horizontal glass capillary tube, where it is collected. This tube is scarcely thicker than a hair. Every 24 hours or so, the tube is removed and divided into tiny sections, the ends of which are sealed. These are the “radium seeds,” which are injected under the skin of patients in the treatment of cancer and other disease. A “seed” is worth about five dollars bi) u ot Hy

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ny PI EET TET ATE I HT ar Vor aN a —* 4 “ os aa . . a soon sisanatinn ibs oar tesine te og ore pemigee 2. ben inn oA lis intn aa Ra caaih Ti atca ita MTT RE ET I PTO NT he NTU ORT MERLE NT eS Lig Sad eRe aS a ike AR SSP aoe ESE POPULAR SCIENCE MONTHLY Ad ventures in Home Ownership Chapter III—We Plan to Build a Permanent Home IRED of paying apartment rent and determined toowna home of their own, Jimand Marion Hunter sought the advice of an old friend, an expert on home buying. The story of their search for a ready-built house, of how they found their hearts’ desire, only to dis- cover that the price was beyond their means, and how they finally decided to buy an inexpensive Dutch Colonial house to live in until Jim’s expected increase in salary should materialize— all this was told in the two preceding chapters. Now read on: on as a neighbor and watch the happy life of Jim and Marion Hunter in their new home. To both of them and to their children, the move from a city apartment to their cozy suburban cottage among the trees had brought health and happiness such as they had not known before. Although the modest home they had bought was not exactly what they wanted, it had answered its purpose admirably until such time as Jim’s promised salary increase should materalize and they were able to build exactly the home they wanted. Meanwhile Jim’s firm and Jim himself, I knew, were making rapid progress, and so it was no surprise to me one Sunday morning, to hear Jim’s voice on the telephone ask- ing me to dine with them. I knew something interesting was afoot. |’ HAD been a positive joy to look OS hasnt the particular oc- casion?”’ I asked, following a ready acceptance prompted by recollections of Marion’s wonderful © home cooking. “The occasion is to hold you to your word,” he retorted. ‘You promised me some good advice whenever I might contemplate building a permanent home, and the time has come.”’ “‘Splendid!”’ “Yes,” said Jim with pride, “I’m a $7500-a-year man now, and can afford a $10,000 to $15,000 home. The Hunters are house-hunting again, but this time it’s building lots and house plans, not completed houses, we’re looking for. We’ve got a few plans here we'd like to have you look over with us.”’ “One thing more,” Jim added, before hanging up. “Our little cottage here proved a good investment as you pro- phesied, and we’ve sold it at a profit of $1000, retaining right of occupancy for six months. In that time we ought to be able to build our own.” Two hours later found us seated about a cleared dinner-table, with a pile of building plans before us. “These plans,” Jim explained, ‘‘are all of houses specially designed for actual clients by an architect friend of mine. All of them have been built, though in other suburbs. I think ‘you'll agree that each has individuality, and in this neigh- By Phil M. Riley Noted American Authority on Architecture and Building borhood any of them would be new.” ‘‘Any reduction for using them second- hand?” I asked. “That’s just the point,’”’ Jim went on. “‘We can have any one of them, if it suits us, without changes, for only a fraction of the usual three per cent of the cost of the house. If we should have the architect’s supervision of the building, the cost would be the usual two per cent.” This, I thought, was the time for a word of good advice! “But unless one under- stands building pretty well or has an exceptionally con- scientious builder, the price of an architect’s supervision “Surely well worth considering if the floor plan pleases you,”’ I approved. OU see,” Jim explained, “the lot Marion spoke of slopes away from the street line rather abruptly, so that the rear party line is probably 10 feet below the street line. Many persons wouldn’t care for such land, but see how easy it is to utilize the basement under the sun porch for a heated garage directly connected with the house. This would save about $1000 for a separate garage, while keeping the whole back yard free for a garden. It also gives a full-height cellar door, which is a comfort.” “And isn’t that sun porch adjoining the living-room just a dear?’ cried Marion. “T certainly agree with you both,” said I. “I notice, though, that there is no open piazza. To me, that Aided by the friendly advice of an expert, Jim and Marion study various architects’ plans to decide on the home they are going to brild for themselves is money well spent,” I commented. “It places responsibility for good materials and workmanship on a competent, in- terested person.” “Probably you’re right,’’ Jim agreed. “Anyway, it would mean only $200 on a $10,000 house.” ‘“‘Where are you going to build?” I asked. “That’s one of the hardest problems,”’ laughed Marion, as she spread out the first roll of plans. ‘‘But let’s take that up as we consider the designs. We like our present location very much, and over on the next street there’s a corner lot for sale on which we think this house would look well.’ Ts house in question was a simple, two-story, gable-roof structure with a porch and doorway with cheerful side- lights, somewhat Colonial in design, plenty of windows well spaced, a sun porch and attractive outside chimney at one end—a house with four attractive elevations that always would be in style and good taste. means more than a sun porch. How about making the house more sym- metrical by adding an open porch on the other end to balance the sun porch?” “WE D thought of that and wanted it,” said Jim; ‘‘but the lot isn’t big enough. It would add 10 or 12 feet to the present frontage of 47 feet, and the lot is only 75 feet wide. It would be crowding things.” “Of course you could have an open porch instead of the sun porch,” I hazarded. “But that would sacrifice one of the best rooms in the hduse,”. protested Marion. “True,’’ I had to admit. ‘Well, let’s look at the floor plan.” It proved to be not greatly unlike that of the house they were occupying, except for the wider central hall with winding stairway, and broad arches leading into the big living-room and dining-room on opposite sides. The living-room had windows front and back and glazed doors opening to the sun porch on each side ofa

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the lot rom that feet sons how der etly yuld age, free ight ling ried said 1ere shat low ym- the 9 ted sn’t feet the be pen . the ted et’s hat ept ing nto 1ad ors of a fireplace, which was situated midway of the length of the room. GOOD feature I noticed was a passage under the head of the stair- way into the kitchen at the rear, a coat closet being located on one side of the passage and the cellar stairs on the other. The dining-room of ample size had the usual pantry between it and the kitchen, with provision for the refrigerator in the rear hall. POPULAR SCIENCE MONTHLY thing else that you value just as much.” “To get all the good features in one house would make some establishment of it,” observed Jim sagely. “The first-floor plan, you see,”’ he went on, “has much the same central hall with the same winding stairway, but connects the front and rear halls through a coat closet, the cellar stairs descending from the rear hall. The dining-room is much the same, but the kitchen combines the 45 the Cape Cod manner. Its frontage is 75 feet, so it’s really a country house. And therein lies a big objec- tion,” he added. ‘That frontage is too much for the average suburban lot. A 100-foot frontage at least is needed for such a house, and it really ought to be from 125 to 150 feet.” “Go half a mile or a mile farther out into any one of several good new de- velopments I know of and you can buy The upstairs floor plan called for four chambers of good size with ample closets, including one in the hall for linen. The bath was located at the rear of the hall above the kitchen; this for plumb- ing economy. At the front end of the hall a built-in table with drawers at each side provided a place at the window for the sew- ing machine, and, in effect, a sort of little sewing-room. “That’s something most archi- tects leave out,’ said Marion, pointing to this interesting pro- vision of the plan. “The home KITCHEN Reap Hau Living Room DintnG Room a | ey Detssinc Room fi Ba As? a | ! rn i i. oe a 1 Cwreas Caamaee pore y | omen | : F nu ml | Courtesy of John Barnard, Architect Floor plans of the house shown above T really is more for the woman than the man,. you know. She stays in it more, and these little things that make for her com- fort are what makes a home homelike.” ‘Now the evidence is in, what’s the verdict?” asked Jim. “ peaeet favorable,” I replied. ‘“‘It’s a home that you can build of brick, stucco, or wood, as you please.” ‘‘Here’s a second one,” said Jim, “‘that resembles the first in ground-floor plan, yet is entirely different in appearance. It is lower, almost a _ story-and-a-half cottage, yet has good second-floor rooms. It is a sort of modernized lean-to adap- tation of the typical Cape Cod farm- house, and has much of the feeling of those quaint old dwellings. This house would go well on that flat vacant lot across the street. It’s hardly the thing for that sloping corner site so well suited to the first house.” “It surely is delightfully picturesque,” said Marion. “But where is my sun porch? It always seems that to get one thing you want, you must give up some- —_j— Courtesy of John Barnard, Architect The house that Jim and Marion decided to build, making a few alterations in the plans to serve their needs. In design it is a modern adaptation of the Cape Cod farmhouse, and should cost about $12,000 pantry with it in one room, a common recent device, I’m told, to save both steps and work. * AND notice the living-room. The fireplace here is at the back end, with built-in bookshelves on each side and doubled glazed doors at the middle of the long side wall opening on to the porch.” “What a cozy place that fireplace with the bookcases would be on a winter’s night,” said Marion. “T’ll say it would be!’’ Jim agreed. “That’s just my idea of a real home picture.” “Again let’s climb the stairs,” urged Marion, spreading out the next sheet. “Here you see the bath is much the same; but I’ve lost my sewing-nook at the front end of the hall, the space being given over to closets. There are only three instead of four chambers, but the owner’s chamber is a lovely big one, with two groups of three windows, two large storage closets under the long slope of the roof and a dressing- room with two wardrobe closets adjoining it at the back. How charm- ing and comfortable it would be when rightly furnished!”’ “Case number two closed,”” announced Jim. “What is the verdict, your honor?” “Very favorable,” I replied. ‘“‘You have an- ‘ Cc other design?” po ~ yf “Yes, one, and to my Barnard, way of thinking it’s a pippin! You see; it’s a scheme for a shingled two-story house after oat, 7 ath wre, = Sec pihaS ‘" “_ half an acre of land at the price of 10,000 square feet here,’ I suggested. “Any of the houses you are considering, if built there, in five years will be worth 25 per cent more than it cost you be- cause of the increased value of the land, which is more than can be said for property right here in this neighborhood. A home in a new development is a_ better moneymaker if you happen to want to sell it later.” xy Rg SOs .oth 2 ‘“FT’HAT sounds good to me, Marion,” Jim exclaimed en- thusiastically. “Suppose we look at some of this land?” Marion agreed. As Jim unrolled the plans of the third house I realized that per- haps it was the most interesting of the lot. By a simple, logical device a small house was made to seem much larger, while the structure had been given a picturesque individu- ality. *“Doesn’t it look worth about $25,000?” Marion asked. “Yes, that’s the deceiving thing about it,’”’ said Jim; ‘for it can be built for about half that sum. What does most to create the impression of size is joining the garage with the house by means of a covered porch. This porch is a comfort in stormy weather.” “The same big living-room, you see,” Marion explained, “except that much of the hall space is thrown into it to make it larger, the only separation being a heavy beam in the ceiling. Think how delightful this stairway would be winding around the fireplace!’ “Back of the hall and stairway,” Jim put in, “‘is a service hall from which a coat closet, toilet and coalbin, or kitchen (Continued on page 135) Caamaee Cramate Cusmore Unusually attractive floor plans of a two-story house of the Cape Cod farmhouse style. Note how the garage is connected with the living-room by a covered porch, in this manner making a comparatively small house seem much larger than it really is

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Trac aEch aceite hae denuded dada neiandtanaaes dakeaan eaeaieneee TAPE TSIE ae PR INN RT BF TE PRT NE ETE IO RES eA Te FE PRPS ee a Se Silas SIE Ga AERO i

omc aeien< mens meancine yee pare er ny as eae 46 POPULAR SCIENCE MONTHLY

— Lupino Lane, famous English comedian (at the left), took his friend Paul Whiteman, American or- chestra leader (at the right), for a spin through London in the former’s baby motor car not long ago, the car ran out of gas and stalled. Result: Lane and Whiteman each took an end and carried Carries Two; Carried by Two in a Pinch the car to the nearest service station. This midget auto is one of the latest developments of the small, completely equipped cyclecar that has become ex- ceedingly popular in England. It is capable of as much speed as the law will allow, and is designed to carry two passengers in a pinch.

“Apartment” Mailbox HE unsightly, straggling groups of rural mailboxes that are such a familiar eyesore at many points along postroads, particularly at crossroad in- tersections, inspired the recent invention of an “apartment” mailbox, of attractive

Serves Many Families design, which receives the mail of several families. The box shown here is designed for three families, but other sizes can be obtained. The boxes are of concrete, with {metal doors, protecting mail against any weather and against theft. The two photographs strikingly illus- trate how widespread use of the new boxes might improve country roads.

Measuring Soil Moisture by Wood Blocks . VERY one has noticed that wooaen doors and drawers stick in wet weather. This property of wood of absorbing water and swelling inthe proc- ess has been utilized by the U. S. Forest Service in measuring soil moisture. Blocks of cypress wood are carefully air-dried, then measured. Then they are put into the ground and left a short time. The amount the {blocks swell is definitely related to the amount of water absorbed, and it is believed that.a corresponding relation can be worked out with the amount of soil moisture.

The neighborhood mailbox, above, is designed to replace unsightly rows of boxes Mechanical Traffic Cop Signals ‘‘Stop’’ and ‘‘Go”’ MECHANICAL traffic officer, dee signed to meet the needs of any street intersection where the bulk of traffic is about equal on both streets, has been invented by Charles S. Kayser, of Montclair, N. J., shown below with a model of his device. It permits traffic regulation at less important intersections, where an officer could not be afforded. At regular intervals, which can be controlled as desired, the device alternates red and green to both traffic currents. A red light on top, supplemented by a gong, gives warning 10 seconds before a change.

Model traffic signal and its inventor “Stop” and “Go” signs turn with the lights. A motor in the base turns continuously, gradually lifting a weight. This weight drops when it reaches a certain height, actuating a system of levers that turns the pillar through a ratchet arrangement. Reinforced Mailbag Offers Protection to Parcels A MAILBAG that will protect parcel- post packages from blows and pres- sure has been perfected by the Post Office Department. The bag is shown here supporting a heavy man, although its contents are only two empty pasteboard shoe- boxes. There arenotransverse braces. The protection is afforded by a reinforce- ment of one-quarter-inch - ply metal placed on each of the two sides. The reinforcement uniformly distributes pressure or the force of blows, causing the contents of the sack te serve as a brace (see illustration at right).

The mailbag supports a heavy man’s weight

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ces 1g, ye. rns el= es- ice orts ight Shoe Rack Attached to the Closet Door ee KEEP shoes always neatly lined in their place, instead of helter-skelter on the floor, or cluttered in shoe-bags, boxes, drawers, or other makeshifts, a neat and simple shoe rack has been designed to screw on the back of a closet door. The rack is of metal and consists of two bars, one above the other. The lower bar protrudes slightly farther than the upper. The heel of the shoe is hooked over the upper bar, while the toe rests on the lower bar. Thus the shoes are held firmly in place, even if the door should be opened or closed abruptly. Shoes rest neatly on the rack Vacuum Tube Radio Set Fits in Briefcase A VACUUM tube receiving set that can be carried in a briefcase, leaving considerable room for papers, has been developed by Walter Palmer, of Brooklyn, N. Y., who claims it is the smallest single- tube receiver ever built; giving results usually obtainable only with more ex- pensive sets. With it, pro- grams from Hast- ings, Neb., and Davenport, Ia., he says, have been heard without dif- ficulty. The Palmer set is a two-circuit re- ceiver, made up of a 43-plate Vernier condenser; a split variometer spe- cially wound in 11 and 40,turns, a rheostat and a grid leak and condenser. ‘The front and back are of bake- lite and no Midget. vacuum tube wires are vis- set completely assembled ible. POPULAR SCIENCE MONTHLY ‘THIs new German tricycle coupé is said to be the world’s lightest and cheapest automobile. So light is it, in fact, that bicycle wheels and tires are used. The small but cozy body protects the driver against the severest weather. An ingenious system of springs protects the Smallest Coupé Travels on Bicycle Wheels 47 fe, 8, z ie driver from shocks due to bad roads. The tiny car is said to average 10 miles an hour on level roads. Because of its light weight, relatively slight traction, and the fact that it is driven by a small motorcycle engine, it will run several times as far on a gallon of gasoline as an ordinary car, the maker claims. Cracked Chimney Salvaged by Angle Irons HE cure for a tall brick chimney cracked from the top nearly to the bottom, would seem to be a stick or two of dynamite. But such a badly cracked chimney not only was salvaged recently, but was made at least as strong as before, by an engineer in a Delaware factory where the damaged chimney was located. The damage had resulted from the ex- pansion of sulphates in the brick; when sulphuric-acid vapor mixed with the waste gases from an_ acid-recovering process. The portion of the chimney to the left of the crack was unharmed, the fissure having occurred when the right portion broke loose and moved to the side. A transit 75 feet distant was sighted on the chimney, points being marked on the _ left portion sq that any movement by it during the work could be detected. Then four-inch angle irons in sections 16 feet long were placed vertically at each corner, held together by seven-eighth- inch wrought-iron rods passing through clips welded to the angle irons and held by bolts. The drawing together began at the bottom, men being stationed at various levels of the staging to tighten the bolts and so pull the irons together. The left portion of the chimney remained im- movable throughout the work, so that when the work was finished the stack was vertical. The crack then was cemented, the bands being left on. Courtesy Hercules Powder Co. Views of the cracked chimney before, during, and after repair —————— ae

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ry ETE ale eR Ao at ynsomanate be Ny ines) 8 Eig —— - . ee eee 46 POPULAR SCIENCE MONTHLY Carries T'wo; Carried by Two in a Pinch “_ Lupino Lane, famous English comedian (at the left), took his friend Paul Whiteman, American 0r- chestra leader (at the right), for a spin through London in the former’s baby motor car not long ago, the car ran out of gas and stalled. Result: Lane and Whiteman each took an end and carried the car to the nearest service station. This midget auto is one of the latest developments of the small, completely equipped cyclecar that has become ex- ceedingly popular in England. It is capable of as much speed as the law will allow, and is designed to carry two passengers in a pinch. “Apartment” Mailbox HE unsightly, straggling groups of rural mailboxes that are such a familiar eyesore at many points along postroads, particularly at crossroad in- tersections, inspired the recent invention of an ‘‘apartment”’ mailbox, of attractive Serves Many Families design, which receives the mail of several families. The box shown here is designed for three families, but other sizes can be obtained. The boxes are of concrete, with jmetal doors, protecting mail against any weather and against theft. The two photographs strikingly illus- trate how widespread use of the new boxes might improve country roads. Measuring Soil Moisture by Wood Blocks . VERY one has noticed that wooaen doors and drawers stick in wet weather. This property of wood of absorbing water and swelling inthe proc- ess has been utilized by the U. S. Forest Service in measuring soil moisture. Blocks of cypress wood are carefully air-dried, then measured. Then they are put into the ground and left a short time. The amount the {blocks swell is definitely related to the amount of water absorbed, and it is believed that a corresponding relation can be worked out with the amount of soil moisture. The neighborhood mailbox, above, is designed to replace unsightly rows of boxes Mechanical Traffic Cop Signals *‘Stop’’ and ‘‘Go”’ MECHANICAL traffic officer, de. signed to meet the needs of any street intersection where the bulk of traffic is about equal on both streets, has been invented by Charles S. Kayser, of Montclair, N. J., shown below with a model of his device. It permits traffic regulation at less important intersections, where an officer could not be afforded. At regular intervals, which can be controlled as desired, the device alternates red and green to both traffic currents. A red light on top, supplemented by a gong, gives warning 10 seconds before a change. Model traffic signal and its inventor “Stop” and “Go” signs turn with the lights. A motor in the base turns continuously, gradually lifting a weight. This weight drops when it reaches a certain height, actuating a system of levers that turns the pillar through a ratchet arrangement. Reinforced Mailbag Offers Protection to Parcels A MAILBAG that will protect parcel- post packages from blows and pres- sure has been perfected by the Post Office Department. The bag is shown here supporting a heavy man, although its contents are only two empty pasteboard shoe- boxes. There are no transverse braces. The protection is afforded by a reinforce- ment of one-quarter-inch , ply metal placed on each of the two sides. The reinforcement uniformly distributes pressure or the force of blows, causing the contents of the sack to. serve as a brace (see illustration at right). The mailbag supports a heavy man’s weight

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he ly, ht nt, nt. el eS- ice orts ight Shoe Rack Attached to the Closet Door T° KEEP shoes always neatly lined in their place, instead of helter-skelter on the floor, or cluttered in shoe-bags, boxes, drawers, or other makeshifts, a neat and simple shoe rack has been designed to screw on the back of a closet door. The rack is of metal and consists of two bars, one above the other. The lower bar protrudes slightly farther than the upper. The heel of the shoe is hooked over the upper bar, while the toe rests on the lower bar. Thus the shoes are held firmly in place, even if the door should be opened or closed abruptly. Shoes rest neatly on the rack Vacuum Tube Radio Set Fits in Briefcase A VACUUM tube receiving set that can be carried in a briefcase, leaving considerable room for papers, has been developed by Walter Palmer, of Brooklyn, N. Y., who claims it is the smallest single- tube receiver ever built; giving results usually obtainable only with more ex- pensive sets. With it, pro- grams from Hast- ings, Neb., and Davenport, Ia., he says, have been heard without dif- ficulty. The Palmer set is a two-circuit re- ceiver, made up of a 43-plate Vernier condenser; a split variometer spe- cially wound in 11 and 40 turns, a rheostat and a grid leak and condenser. ‘The front and back are of bake- lite and no Midget vacuum tube Wires are vis- set completely assembled ible. POPULAR SCIENCE MONTHLY ‘Ts new German tricycle coupé is said to be the world’s lightest and cheapest automobile. So light is it, in fact, that bicycle wheels and tires are used. The small but cozy body protects the driver against the severest weather. An ingenious system of springs protects the Smallest Coupé Travels on B _— icycle Wheels driver from shocks due to bad roads. The tiny car is said to average 10 miles an hour on level roads. Because of its light weight, relatively slight traction, and the fact that it is driven by a small motorcycle engine, it will run several times as far on a gallon of gasoline as an ordinary car, the maker claims. Cracked Chimney Salvaged by Angle Irons Sane cure for a tall brick chimney cracked from the top nearly to the bottom, would seem to be a stick or two of dynamite. But such a badly cracked chimney not only was salvaged recently, but was made at least as strong as before, by an engineer in a Delaware factory where the damaged chimney was located. The damage had resulted from the ex- pansion of sulphates in the brick; when sulphuric-acid vapor mixed with the waste gases from an _ acid-recovering process. The portion of the chimney to the left of the crack was unharmed, the fissure having occurred when the right portion broke loose and moved to the side. A transit 75 feet distant was sighted on the chimney, points being marked on the left portion sq that any movement by it ’ during the work could be detected. Then four-inch angle irons in sections 16 feet long were placed vertically at each corner, held together by seven-eighth- inch wrought-iron rods passing through clips welded to the angle irons and held by bolts. The drawing together began at the bottom, men being stationed at various levels of the staging to tighten the bolts and so pull the irons together. The left portion of the chimney remained im- movable throughout the work, so that when the work was finished the stack was vertical. The crdck then was cemented, the bands being left on. Courtesy Hercules Powder C», ——EEEE Views of the cracked chimney before, during, and after repair FE BE NA BRIO PR VE I Se ———

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Ee POE ITE IELTS EOL TTLE DETER i} 4 - a: t ‘ Bi POPULAR SCIENCE MONTHLY See Sa Ramee Metal Strip Alines Paper for the Typist O SAVE the typist time and annoy- ance, sheets of carbon are alined with sheets of paper by a simple metal strip attached to the typewriter frame just in front of the space bar. The strip is set at an angle to form a narrow trough into which the tops of the sheets are inserted. Jigging the sheets a little then alines them. Powerful Headlight Casts Beams of Two Colors HEADLIGHT beam of two colors— intense white at the bottom and at the top a soft yellow filtered free of daz- zling rays—is thrown by the new auto- mobile lamp shown above. Both the lights are said to be unusually brilliant because of the four-inch lens opening, made possible by an almost com- pletely elliptical reflector, housed in an attractive egg-shaped casing. Illumination of the road for a distance of 500 feet is possible, the inventor claims. Yet approaching motorists see only a strong but soft and harmless glow. The white portion is deformed by the lens to an inverted fanlike section. A novel focusing device makes it easy to adjust the position of the lamp fila- ment. Water Gives Clue to Oil AN ANALYSIS of the gases dissolved in underground water may give a clue whether the soil through which it has seeped contains oil. If it traverses sand containing oil or natural gas, it will dis- solve a proportion of the hydrocarbons of which the oil or gas is composed. When the water then is exposed to the air at the surface, the vapors will be driven off and their place taken by air. The vapors can then be analyzed. The United States Bureau of Mines has de- vised a portable apparatus that may be used for this purpose. Indicator Stops Car when Speed Limit Is Passed ETTING the bottom indicator on this new automobile speedometer at a cer- tain number makes it impossible for a driver to go more than that many miles an hour. When the car reaches a speed three miles less than that shown on the dial, a signal light flashes. When the indicated speed is exceeded, the ignition is cut off automatically, going on again when the car returns to the dial-indicated speed. The instrument also indicates in de- grees the grade the car is climbing and shows if rear light is burning. Baby’s Blankets Fastened HE sleeping child is kept covered at night by this new blanket fastener with teeth that engage the upper edges of the covers. It is attached to the bed- posts by an elastic band. Makes Odd Designs from Cancelled Stamps UTTING curious composite pictures and designs from canceled postage stamps of many nations is the unique hobby of George Gage, an artist of Brook- lyn, New York. : He has found limitless the attractive and fantastic creations possible with a few stamps and a pair of scissors. The designs of the stamps, he says, have given him some of his best inspirations, although usually he adapts them to his conceptions. The many colors and varied, complicated designs of most stamps offer wide variety in arrangement and an interesting field for the hobby-lover. George Gage, Brooklyn artist, is shown above cutting out cancelled stamps, which he uses in making unusual designs— his hobby. A number of his creations are shown in the illustration at the right

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this cer- or a niles hree al,a ated t off the de- and d at ener Ss of ed- One Man Can Fell a Tree with This Dragsaw ONVENIENTLY operated by one man, this dragsaw, which also can be used as a crosscut, makes tree-felling without a saw-mate far easier than here- tofore. It is the invention of Frank Fox, Chesaw, Wash. The free end of the saw is attached to a block, which slides on a thin plank. The plank is supported in a horizontal position by prongs that engage the tree, and by brace members supporting the end, as shown in the illustration. A spring fastened to the end of the plank and also attached to the block tends to pull the saw away from the operator at the end of a cut. Where the saw cuts into the tree is a roller mounted on a spike or arm that is driven into the tree, preventing the saw from sagging. A Four-Socket Wrench NY one of the four socket wrenches arranged i in a turret head, as shown above, is made available instantly by a twist. The tool is designed for tire-rim. work. The brace gives powerful leverage. POPULAR SCIENCE MONTHLY 49 TZ Supports a Motorcycle Race on His Chest HE legendary feats of old-time strong men are made more plausible by this astonishing performance, verified by photography. Sigmund Breitbart, a Polish Samson, is shown supporting on his chest and knees a motorcycle track 30 feet in diameter, on which two motor- cyclists are racing. The total weight supported by his powerful body is 3500 pounds—a ton and three-quarters. Business Block Is Heated by Exhaust Steam WHOLE row of business buildings in Pittsfield, Mass., now is heated by the exhaust steam from a 750-kilowatt turbo-generator used by a local power company. The steam is conducted to the generator through what is believed to be the longest high-pressure steam line in the world. It is 3600 feet long, carries the steam at a pressure of 195 pounds, and is built partly under and partly above the ground. The pipe is eight inches in diameter and covered by three inches of insulation and a protective jacket of heavy duck. To waterproof the whole, a three-ply wrapping of roofing paper is used. Two Can Play Piano with Double Keyboard A PIANO with two keyboards, sim- ilarly pitched, allowing two persons to play the instrument simultaneously, without interference, is the invention of Dr. Moriz Stoehr, professor of bacteriology at Mt. St. Vincent College, New York. Doctor Stoehr also is the inventor of a typewriter that transposes and records music and of a piano key- board with shortened black keys, described in our March issue. The double keyboard consists of two banks of keys shortened to fit in the space ordinarily occupied by one. Both key- boards operate the same hammers. The double keyboard (above), and method of operation (at left) Three Screwdrivers and a Hammer in One Tool HREE screwdrivers in the handle of this machinist’s hammer will serve for any size of screw ordinarily encountered, from the tiny ones used on portable typewriters to those in large strap hinges. A few twists of the handle fastens any one of them in the bit. The hammer is 7% inches long, and the drivers are 5144, 2%, and 14% inches long respectively. ‘‘Ivory’’? Grows on Trees IN COLOMBIA, Peru, Ecuador, and Brazil, ivory grows on trees. Chess- men, ornaments, buttons, drawer-knobs, and other articles are made from this vegetable ivory which, when dried and cut, looks like the real ivory obtained from elephant tusks. It is gathered in the form of hard, white, fine-grained, oval nuts, about the size of a small potato, which drop from the wild tagua or ivory-nut palm.

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a ee * SBR RENLON GRE CEE A ANGEL SOT NED > sareecoh> 1 jrestdeidacadesa et eatmare saan aha ue ec oh adhe aS le aged Bees a 478 Sma Serer ig ct. ha en aa li ics hei als 1 ST Seth eReNED es sare sibs renee es cee CR ANN IR SNE EI REE TEA I Ses a rae Sects ei SO ost é POPULAR SCIENCE MONTHLY Metal Strip Alines Paper for the Typist O SAVE the typist time and annoy- ance, sheets of carbon are alined with sheets of paper by a simple metal strip attached to the typewriter frame just in front of the space bar. The strip is set at an angle to form a narrow trough into which the tops of the sheets are inserted. Jigging the sheets a little then alines them. Powerful Headlight Casts Beams of Two Colors HEADLIGHT beam of two colors— intense white at the bottom and at the top a soft yellow filtered free of daz- zling rays—is thrown by the new auto- mobile lamp shown above. Both the lights are said to be unusually brilliant because of the four-inch lens opening, made possible by an almost com- pletely elliptical reflector, housed in an attractive egg-shaped casing. Illumination of the road for a distance of 500 feet is possible, the inventor claims. Yet approaching motorists see only a strong but soft and harmless glow. The white portion is deformed by the lens to - an inverted fanlike section. A novel focusing device makes it easy to adjust the position of the lamp fila- ment. Water Gives Clue to Oil N ANALYSIS of the gases dissolved in underground water may give a clue whether the soil through which it has seeped contains oil. If it traverses sand containing oil or natural gas, it will dis- solve a proportion of the hydrocarbons of which the oil or gas is composed. When the water then is exposed to the air at the surface, the vapors will be driven off and their place taken by air. The vapors can then be analyzed. The United States Bureau of Mines has de- vised a portable apparatus that may be used for this purpose. Indicator Stops Car when Speed Limit Is Passed ETTING the bottom indicator on this new automobile speedometer at a cer- tain number makes it impossible for a driver to go more than that many miles an hour. When the car reaches a speed three miles less than that shown on the dial, a signal light flashes. When the indicated speed is exceeded, the ignition is cut off automatically, going on again when the car returns to the dial-indicated speed. The instrument also indicates in de- grees the grade the car is climbing and shows if rear light is burning. Baby’s Blankets Fastened HE sleeping child is kept covered at night by this new blanket fastener with teeth that engage the upper edges of the covers. It is attached to the bed- posts by an elastic band. Makes Odd Designs from Cancelled Stamps UTTING curious composite pictures and designs from canceled postage stamps of many nations is the unique . hobby of George Gage, an artist of Brook- lyn, New York. He has found limitless the attraction and fantastic creations possible with a few stamps and a pair of scissors. The designs of the stamps, he says, have given him some of his best inspirations, although usually he adapts them to his conceptions. The many colors and varied, complicated designs of most stamps offer wide variety in arrangement and an interesting field for the hobby-lover. George Gage, Brooklyn artist, is shown above cutting out cancelled stamps, which he uses in making unusual designs — his hobby. A number of his creations are shown in the illustration at the right

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this cer- ra niles hree al, a ated 5 Off the de- and 1 at ner s of ed- a... \ One Man Can Fell a Tree with This Dragsaw Coeere operated by one man, this dragsaw, which also can be used as a crosscut, makes tree-felling without a saw-mate far easier than here- tofore. It is the invention of Frank Fox, Chesaw, Wash. The free end of the saw is attached to a block, which slides on a thin plank. The plank is supported in a horizontal position by prongs that engage the tree, and by brace members supporting the end, as shown in the illustration. A spring fastened to the end of the plank and also attached to the block tends to pull the saw away from the operator at the end of a cut. Where the saw cuts into the tree is a roller mounted on a spike or arm that is driven into the tree, preventing the saw from sagging. A Four-Socket Wrench NY one of the four socket wrenches arranged i in a turret head, as shown above, is made available instantly by a twist. The tool is designed for tire-rim. work. The brace gives powerful leverage. POPULAR SCIENCE MONTHLY Supports a Motorcycle Race on His Chest HE legendary feats of old-time strong men are made more plausible by this astonishing performance, verified by photography. Sigmund Breitbart, a Polish Samson, is shown supporting on his chest and knees a motorcycle track 30 feet in diameter, on which two motor- cyclists are racing. The total weight supported by his powerful body is 3500 pounds—a ton and three-quarters. Business Block Is Heated by Exhaust Steam WHOLE row of business buildings in Pittsfield, Mass., now is heated by the exhaust steam from a 750-kilowatt turbo-generator used by a local power company. The steam is conducted to the generator through what is believed to be the longest high-pressure steam line in the world. It is 3600 feet long, carries the steam at a pressure of 195 pounds, and is built partly under and partly above the ground. The pipe is eight inches in diameter and covered by three inches of insulation and a protective jacket of heavy duck. To waterproof the whole, a three-ply wrapping of roofing paper is used. Two Can Play Piano with Double Keyboard A PIANO with two keyboards, sim- ilarly pitched, allowing two persons to play the instrument simultaneously, without interference, is the invention of Dr. Moriz Stoehr, professor of bacteriology at Mt. St. Vincent College, New York. Doctor Stoehr also is the inventor of a typewriter that transposes and records music and of a piano key- board with shortened black keys, described in our March issue. The double keyboard consists of two banks of keys shortened to fit in the space ordinarily occupied by one. Both key- boards operate the same hammers. The double keyboard (above), and method of operation (at left) Three Screwdrivers and a Hammer in One Tool HREE screwdrivers in the handle of this machinist’s hammer will serve for any size of screw ordinarily encountered, from the tiny ones used on portable typewriters to those in large strap hinges. A few twists of the handle fastens any one of them in the bit. The hammer is 7% inches long, and the drivers are 514, 2%, and 14 inches long respectively. ‘‘Ivory’’ Grows on Trees N COLOMBIA, Peru, Ecuador, and Brazil, ivory grows on trees. Chess- men, ornaments, buttons, drawer-knobs, and other articles are made from this vegetable ivory which, when dried and cut, looks like the real ivory obtained from elephant tusks. It is gathered in the form of hard, white, fine-grained, oval nuts, about the size of a small potato, which drop from the wild tagua or ivory-nut palm.

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cara eracees Seg pete i a) Sree ere POPULAR SCIENCE MONTHLY Elastic Roadside Fence Invented to Protect Cars from Disaster HOULD your car, swerving from the road at 45 miles an hour, strike this fence at the edge of an embankment, you would be halted unhurt, its inventors claim. The picture above shows the result of such an encounter in a test near Bridgeport, Conn. Placed at dangerous turns, on bridges, and bridge approaches and along mountain roads, such fencing, it is as- serted, would save scores of lives each year. Forty per cent of highway ac- cidents are said to happen on such roads. The fencing is of specially woven wire, rugged and elastic, elongating like a rubber band when struck. It stretches until the wires forming the meshes touch each other, so that it halts the car without sudden, destructive impact or injury to a car’s occupants. The recoil pushes the car back several feet if it is traveling moderately fast. At higher speeds, the fence conforms some- what to the lines of the car. Protector for Door Lock Keeps Burglars Out ge paren in the glass or wood panel of a door equipped with this new protected lock would not permit a burglar to unlock and open the door from within. Of course, he could go on and smash out a hole large enough to admit his body. But, besides the difficulty and time, the incidental noise would increase the danger of discovery and capture. The metal protecting device covers the inside knob and catch of the lock, fastening over them automatically when the door is closed and releasing when the key is turned. Melt Ice from Power Lines A BALTIMORE power company has found a way to prevent sleet troubles along its lines. The company’s operators keep close tab on the weather. When the ice begins to form, enough cur- rent is applied to the circuit to melt the sleet. Success depends upon getting started before the sleet gains headway. A Mechanical Memory for Card Players HOSE deal is it? The answer to this question often becomes a stumbling-block to an otherwise smoothly running card game. Few closely con- tested games progress far before there is a clash of opinion on this point or a frank confession of ignorance all around. But now comes a newly invented scoring device equipped with a me- chanical memory to relieve the situation. It consists of a mechanism actuating a dial that points to each of the players in turn from right to left. This mechanism is actuated by pressure of the scoring pencil as it is thrust against the bottom of its holder, which is a part of the device. At the start of the game the pointer is set toward the player at the dealer’s left. When the score for that hand has been recorded, the new dealer having begun to shuffle, the pencil is returned to the holder by the scorekeeper. This causes the pointer to indicate the person at the left of the new dealer. The complete outfit includes, in ad- dition to pointer and pencil, containers for two decks of cards. ‘Modern Uses for Sulphur ULPHUR formerly was used in matches—the eight-day kind. People got tired waiting for these to burn, so the matchmakers began Scoring the last hand while the new dealer distributes the cards. The memory device is shown resting on the score pad. When the scoring is completed, the pencil is thrust into a socket, causing a pointer to turn toward the player whose turn it is to deal next. The complete device is shown at the right to leave out the sulphur. Nowadays they use it for vul- canizing rubber and making gunpowder and sulphuric acid. Likewise sulphur is good for killing the bugs on trees, so they put it in sprays.

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shes the act eral At me- r is eft. een 1 to the ses the ad- Lers in ple the yan the ays POPULAR SCIENCE MONTHLY SS ros : i é ; , " ‘Ny “wi, ies? ee Co > EEP in the thick mud of the Hudson River’s bed, the builders of the great twin vehicular tunnels to connect New York City and New Jersey are advancing foot by foot. Before the tunnels are completed, early in 1925, millions of tons of mud must be removed, deposited on scows, Where Tunnel Builders Are Boring in Mud under the Hudson and dumped in New York harbor. The work of excavation is performed in a series of compressed-air chambers, each with a higher pressure than the one behind it. High pressure in the foremost chambers prevents the river bed from crushing the tunnel walls and overwhelm- ing the workmen with mud and water. 51 ; The intermediate chambers are neces- sary so that the bodies of the workmen may adjust themselves gradually to the pressure in the last one. Even against the pressure within, the mud from the great cutting shield enters as shown above. Here it is shoveled into cars which carry it out for disposal. Truck, Tractor, and Mobile Crane Combined COMBINED truck, tractor, and mobile crane, so compact that it can enter and turn around in a freight car, has been invented to meet the needs of transportation in such places as ship- ping yards, warehouses, and large fac- tories. The machine runs on three wheels. It will tow from seven to 10 tons, or from one to 20 trailers, according to the condition of the floor or yard. The crane is an accessory that can be attached in five minutes. It will lift and carry loads up to 2000 pounds. A brake device permits this load to equilibrium is given by the 40-inch wheel base and the 33-inch tread. The machine is particularly useful in loading and unloading box cars, in lifting and towing loads along narrow aisles, and for interplant haulage. TYPHOID is becoming an almost un- known disease in many American cities, according to a survey by the Journal of the American Medical Association of deaths from that cause in cities of more than 100,000. be carried at any height up to 56 inches. The 16-inch wheels wear 34-inch solid tires, providing ample traction under the heaviest loads. Solid The compact machine is shown above in use as a tractor, hauling a train of small trailers over the floor of a factory. It is capable of towing from seven to 10 tons. At the left is the same machine with crane attached. This crane can lift and carry loads up to 2000 pounds ‘“Tather Gun’’ Does Work of a Shaving-Brush EVERAL handfuls of shaving lather of unusually delicate texture are worked up within 30 seconds from the time a man picks up this new sanitary “lather gun.” Because it obviates cup and brush, with their danger of infection, its makers claim that it is particularly valuable for barbers. Water is poured into a side opening of the device, which contains a soap car- tridge. Just enough water for one shave is admitted. A cap on the opening is re- placed. Then two easy squeezes of a bulb force out lather through a nozzle in a thick, continuous stream. Soap cartridges of special size and shape are used. The air from the squeezed bulb drives the water about the soap and into a chamber above. Through tiny holes it enters against curved surfaces, which give it a strong whirling motion. By a series of channels the lather then is forced six times through two fine mesh screens. These screenings achieve the delieate texture of the lather, which is applied by the hands.

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POPULAR SCIENCE MONTHLY

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—* enough lumber for a small bungalow—8500 board feet—is in this ponderous cut from the body of a California mountain giant. High in the Sierras, where stretch some of the world’s richest timber reserves, the great tree was felled by lumberjacks with crosscut saws, toppling at the last urge of Lumber for a Small House in This One Log wedges and crashing with a roar audible across a valley. Voracious power saws bit it into sections in no more time than was required for the single felling cut. A truck is shown bearing the huge log to the mill, where sawyers on sliding platforms fashion it into required sizes and shapes.

Powerful New Pipe-Wrench Is Self-Adjusting ‘ys powerful but simple new pipe- wrench instantly adjusts itself to any width within the limits of its jaws. It cannot slip, its inventor claims, for the jaws are so arranged that the more pres- sure placed upon them, the more relent- lessly they hold. Because of this, the wrench can be hung on a pipe safely. It will not throw its user backward by slip- ping during a hard pull. The manner of gripping permits it to be used in many places inaccessible to ordi- nary wrenches. Instant adjustment is obtained by means of a spring and an ingenious arrangement of joints—shown below in the in- set — connecting the two jaws.

The new pipe-wrench shown in use

pk Snaky Climb Reduces Grad 13 per Cent gee ab ai a 30-per-cent grade to one of 17 per cent, San Francisco city engineers recently transformed a danger- ous hill of Lombard Street in the zigzag manner shown. The arrangement, pleasing to the eye, is particularly suited to streets as steeply graded as this one in fine residential districts. e

New YorK state leads all the others in the amount of water-power devel- opment — 1,300,000 horsepower. The largest single development is at Niagara Falls. The second state in the use of “white coal” is California, where more than 1,100,000 horsepower is developed. Washington holds third place, using 454,000 horsepower. Maine is fourth with a few thousand horsepower less, and Montana fifth. Huge Pattern for Hawse Pipes of ‘‘Leviathan”’ HE wooden pattern shown below, weighing nearly 1000 pounds, and containing 3000 feet of lumber, will be one of the two used in casting the new steel hawse pipes through which the great steamship Leviathan’s 12-ton an- chors will be controlled. These will replace old cast-iron pipes, worn through by the anchor chains, They will be the largest ever made in the United States, each weighing 12 tons, They are 18 feet long.

Wooden pattern for giant hawse pipe

Butter Churned and Worked in 30 Minutes UTTER ready to cut in blocks in 30 minutes is the feat claimed for a new combined churn and worker. The fact that no handling is necessary during the process results in greater sanitation than the usual home process. The new machine is a wooden drum churn with one working roll and one idle roll. The drum revolves with the cream for 15 minutes, either by hand or power. The buttermilk then is drained at the bot- tom, and warmed water is poured in. A few revolutions wash the butter. The churn then is thrown into low gear and in 10 minutes the butter is thoroughly worked and ready for the market. Moisture and salt are added during this last process. Three sizes of this churn are made, with ca- pacities varying from 12 to 40 gallons.

A housewife operating the r.ew churn

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0 ct 1e in le T. t- ar ly t. ‘is of re a- ng 10) Simply Built Frame Aids in Photographing Books | genie tnipees agate pages of a book can be made easy by a simply con- structed frame for holding them flat. Especially for a large or a new volume, such a device will save you time and patience. It consists chiefly of a block of wood 121% by 16 inches with metal brackets on each side for holding two clamps that flatten the pages. If the page to be photo- graphed is near the front or back of the book, another book or pamphlet should Clamps hold the book pages flat be placed under the thinner portion to make the metal brackets fit sungly. A piece of plate glass is clamped on top of the pages, as tightly as necessary to take out the curve near the stitch of the volume. Three strips of wood should be placed under the clamps to equalize the pressure and prevent the glass from breaking. The book now can be placed under a vertical camera, or in the horizontal posi- tion. Less than a minute will be required to adjust it properly. The holder is particularly valuable for copying illustrations, such as maps, which cover two pages. Cold Sealing-Wax Squeezed from a Tube Go seems the day when burned fingers and a scorched envelope often were the price of sealing a letter with wax. For a cold sealing-wax has been developed, one claimed also never to crumble or crack. You merely squeeze the desired quan- tity of wax from a _ tube to. the envelope and imprint theseal. Within a few seconds the wax is hardened into a symmetrical seal, made pos- sible by the cold wax. No heating is required for sealing POPULAR SCIENCE MONTHLY HE slow, mighty strength of tides was employed uniquely recently when it was made to lift this old railroad bridge on San Francisco Bay and tow it nearly a mile down the bay. The structure was moved in its entirety in less than a day, without the slightest damage. Shortly after midnight, at low tide, Power of Tides Used to Move Old Bridge several hundred men fell quickly,to work. A number of barges were floated under the bridge. Toward dawn, the rising tide lifted the ponderous structure from its concrete bulkheads and bore it down the bay. The photograph above shows the lifted span resting on the barges. Improved Bicycle Brake Acts against Rim ERY slight pressure on the brake lever is required to stop bicycles equipped with a recently invented brake consisting of bowed arms that encircle the front wheel and : press against the edges of the rim. These arms are operated by a bow spring, which in turn is connected with a brake rod and oper- ating handles on the handle-bars. The rim-brake arms are pivotally mounted on clips attached to the front fork of the bicycle. The great leverage minimizes the braking pressure required. Advertisements Animated by a Coilspring OR 25 years advertising men have been seeking a practical method of animating display advertising cards used on streetcars and buses. All kinds of mechanical devices have been tried without success, until E. E. Gregory, of Louisville, Ky., who has patented four display advertisement methods, conceived the idea of suspend- ing on a coiled spring any portion of the advertisement that it is desired to ani- mate. The jolting of the car or bus initi- ates the movement. In this manner the boy’s hand in the advertisement shown below is moved up and down rapidly. The idea now is being used on the Fifth Avenue coaches of New York City. Road jolts move the boy’s hand

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54 POPULAR SCIENCE MONTHLY Clever New Inventions that The danger of dirt and dis- ease in ice-water is elimi- “Saving the crumbs” becomes an easy matter nated by the newly in- for the economical housewife with this roomy vented vessel shown above, and sanitary new bread cabinet. The cover of which cools the water the cabinet swings downward to form a bread while keeping the ice board, at one end of which is a pocket-like separate from it. The ice container into which crumbs can be scraped is placed in the tubular center container and cov- ered, while the outer con- tainer is filled with water Three different brushes and two handles are in- cluded in this new brush set, which can be used to wash windows, sweep car- pets, hang pictures or wall- paper, clean the tops of moldings, walls, and ceil- ings. One handle is for walls, another for floors The tedious task of cutting up washing soap is eliminated by this time-saving soap shaver. Rubbing acake of soap across the device a few times is said to provide enough shavings for a large washing One of the simplest broom holders imaginable is this bent piece of metal fastened to the wall. The broom handle is inserted through the hole from the bottom, and the plate pinches it against the wall A baby in the arms becomes a heavy load after a few minutes. To relieve parents of this burden a French inventor had devised the simple, yet convenient carrier shown above. A strip of canvas in which the child rests terminates in two handles, one on each side. pe Guards at the front and rear keep Nie : a ee ee the baby from falling out a : : : ; ; This ingenious little tray for the table after-dinner ashtray, to obviate ash-spill- serves a double purpose—as a rack for ing on greasy plates. For the latter pur- the knife, fork, and spoon, and as an _ pose the rack is turned aside in its socket

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POPULAR SCIENCE MONTHLY 55 ake Housework a Pleasure Numerous small cleaning jobs about the house and garage are accomplished neatly with the little implement shown above— a double-edged blade of specially molded rubber attached to a short wooden handle. The lower, curved edge is used for scraping pots and pans, while the straight edge, for cleaning windows, gathers all the moisture and dirt from the window edges This attractive sewing-basket stand folds to half its width. Numerous compartments within the bag hold the sewing materials In this 714-pound vacuum cleaner, the bag and motor are concealed in the aluminum housing on the floor The capacity of a closet is said to be greatly increased if the clothes are hung from the seven-to-the-bar hooks shown above. Suits and gowns on hangers can be arranged in space-saving rows. The hooks are useful also for hanging kitchen utensils, dustcloths and brushes, or for holding tools in the workshop The odd cover of this new glass jar for jam or pickles has been invented to protect the con- tents from dust and con- tamination. The cover incloses the end of the preserve spoon Objectionable odors of cooking and discoloration of kitchen walls by grease are said to be eliminated by a new filtering flue designed to fit the vent of any gas oven, as illustrated above. The device can be attached in a minute without tools, the manufacturers say

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ion POPULAR SCIENCE MONTHLY ~ Fait OOD in general, and valuable piling along waterfronts in particular, are the favorite delicacies of these destructive wood-boring marine pests, scientifically called ‘“‘Limnoria.”” Against them the resources of the United States Forest Service’s Forest Products Laboratory are being marshaled. These tiny creatures, the largest never more than a quarter of an inch long (those shown above are highly magnified), Marine Pests Bore into Creosoted Piling are a serious problem on both the Atlantic and Pacific coasts. Coming in contact with piling through the chance of tide or drift, and lodging in a crevice or on the surface, they eat away the soft wood, leaving the remainder in riblike ridges. After a time a pile may snap in two. Limnoria are harder to combat than are other marine pests with a taste for wood, because they will penetrate wood impreg- nated with creosote. bal wil Leafless, Branchless Tree | Phew a recent exploring expedition into the desert mountains of Sonora, Mexico, Dr. D. T. MacDougal, of the Carnegie Institution’s Laboratory of Plant Physiology, Tucson, Ariz., dis- covered the strange leafless and branch- less tree shown above. He believes the members of his party were the first white men to see this remarkable evergreen. The trunk, resembling an almost bare column, is of soft, pithy growth. The only features resembling limbs are the slender spines that bristle from the trunk. PERSIMMONS are scheduled to rise in popularity. At last a persimmon that will not pucker the mouth has been found. It is the Fuyu persimmon, which comes from Japan. U. S. Imports Giant yan, some species of which are said to be as high in food value and as palatable as white potatoes, although weighing up to eight pounds, soon may be enlarging the nation’s food supply. Uncle Sam’s Plant Bureau has imported a number of species from the West Indies and is experimenting with their cultivation. These tubers give enormous yields to the acre. The bureau’s experts now believe that they can be grown in Cali- fornia, in the Gulf states and as far north as Charleston, S. C. They are said to taste much like white potatoes. In tropical countries they supply much of the food of millions of persons. Yams weighing 100 pounds can be grown, but from three to eight pounds seems the most de- sirable weight. The yams may be baked or boiled, and The “greater yam,”’ grown in South Atlantic and Gulf states regions Odd Tree-Climbing Fish Can Jump Six Inches MO “ION-PICTURE _ expedition soon will leave for Ceram, an island of the Malay Archipelago, to make films of a remarkable tree-climbing fish that is found nowhere else in the world. The expedition is sponsored by William H. Thompson, former mayor of Chicago. The fish is about nine inches long. It is said to spend most of its time on land, chasing the insects on which it feeds. In pursuit of its prey, it is said, the fish sometimes climbs 40 feet or more up the aerial roots of a kind of fig-tree that grows along the island’s marshy shores. These fishes climb with leglike fins It lives in a burrow in the muddy shal- lows. It climbs with a pair of ventral fins, suggesting legs, and highly developed pectoral fins, like arms. Its usual way of covering ground, however, is jumping. It can jump about six inches. Tiny gill-slits, conserving moisture, allow the fish to stay out of water. Rivals of the Potato a variety of dishes approximately equal to the number that can be made from potatoes, are said to be possible with them. The dasheen is another vegetable said to resemble the potato in flavor. a a ee eee ee ee ae ~_

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ion ind ms L is “he It nd, ds. fish the hat res. hal- ins, ped y of ing. ure, yual rom vith said Powerful Beacons to Guide Aviators at Night OWERFUL 450,000,000 candlepower eyes like this one are to gleam through darkness, fog, and storm from government landing-fields to guide aviators to safety. Its mighty beam is said to be visible for 130 miles through ordinary darkness. The searchlight beacon is equipped with a dispersion lens that, if directed along the ground, is said to make as light as day a fan-shaped area a quarter of a mile wide by a half mile deep. 459,000,000- candlepower beacon for airplanes Workmen’s Efficiency O LEARN why some workmen ac- complish more than their fellows with less effort, motion-picture films of men at work are analyzed on the ingenious drafting table shown below. The films are not projected, but studied directly on the roll. They are run through a cabinet shown at the left of the table. A strong light within the cabinet brings out the minutest details of each picture. A slit down the face of the cab- inet, through which the pictures are seen, allows about 25 to be visible at a time. These are studied one by one, pains- takingly, with a magnifying glass. The drafting paper, on a continuous roll, is ruled horizontally and perpendicu- larly. The horizontal lines indicate units POPULAR SCIENCE MONTHLY 57 wre) +3) rs . Rt wt & waddle * ad " : te fe © Western Electric Co. A Machine that Talks with Electric Voice HIS machine talks—not as a phono- graph talks, by reproducing a re- corded voice—but with a voice of its own. It is not a highly educated machine, for its sound repertoire is limited to the vowels and to a few simple combinations with consonants. For example, it is said to utter ‘‘Mama” and “‘Papa”’ plaintively. Its artificial voice speaks when vibra- tions from a vacuum tube oscillator are fed into an overloaded vacuum tube. Two Analyzed by Movies of time—2000 to a minute; the perpen- dicular lines represent those parts of the laborer’s body involved in the work. Thus graph lines, rising and falling with the slightest changes in the time required for the various movements making up the work, and moving to right and left as the parts of the body move with the work, present a minutely detailed story of the workman’s movements. These movements then are criticized with a view to further elimination of waste motion and time. ENGLAND now has the first lighthouse for automobiles. It has been erected on a dangerous hill between Birmingham and Manchester to guide motorists at night. Charting bodily movements shown on the film The drafting table and film cabinet tuned circuits are coupled to the output and the resulting complex sound is fed into a loudspeaker. The voice is closely related to the howls and squeaks that sometimes issue from a radio receiving set. The photograph shows the machine in the laboratories of the Western Electric Company. Magnet Removes Steel from Patient’s Eye peer esp of surgery, a powerful mag- net was used recently to remove a piece of steel embedded in a woman’s eye. Dr. D. T. Vail, of the Massachusetts Eye and Ear Infirmary, is shown above operat- ing the magnet, which is so powerful that it could lift a solid steel table. Placed with its tip close to the patient’s eye, it quickly drew the deeply embedded bit of steel to the surface of the eyeball. Many valuable uses are predicted for this magnet, and for more powerful ones that may be built. Operations for re- moval of foreign objects from delicate organs, such as the brain or the heart, can be made safer and less painful by its use, it is said.

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58 A Light, Unsinkable + ay ce eee ciao 7s haa SRE ACRE REET heii HIS 30-pound, unsinkable canoe, con- structed of cypress, makes a splendid sport easier to follow, simplifying the problem of portage and minimizing dan- ger of accident. A boy can carry it. POPULAR SCIENCE MONTHLY Canoe for the Camper This canoe can be carried by a boy — and it won’t sink Although the midget craft will hold two persons, any considerable cargo of sup- plies would limit it to one passenger. Its lightness makes it easy to paddle and easy to carry. Watertight bulkheads at each end make it unsinkable. The canoe is especially suited to the needs of youngsters learning to be waterwise. It can be lashed easily to the runningboard.of a car. Airplane Propeller Drives Odd Motor-Car RIVING an automobile with an air- plane propeller at a top speed of 90 miles an hour, Harry and Martin Sensen- ich, of Lititz, Pa., claim to have developed an efficient mo- tor - car that eliminates dif- ferential gears, transmission, and jerk in starting. They assert that its gasoline consumption is no greater than that of any other car of similar power. An 80-horsepower rotary airplane en- gine drives a four-bladed airplane pro- peller six feet in diameter. The body of the car is of airplane material, covered with linen. Absorbing wheels used on airplanes carry this odd car. ee oat ' * « 4 * 1 a bg : c &y An airplane propeller in front drives this car at a speed of 90 miles an hour Greenwich Clock Records Birth of Each New Day HE world’s most important timepiece is the chronometer, pictured below, in the Royal Observatory, at Greenwich, England. It officially records Greenwich meridian time. There the birth of each new day is recorded for the world, for there it is midnight before it is midnight anywhere else on earth. Henceforth, this time is to be broadcast from the observatory at regular intervals. Thus English radio enthusiasts may keep their watches and clocks precisely right, ready to hail each new day at the exact moment of its birth. The chronometer at Greenwich, England They'll See Us in Movies in the Year 6924 EOPLE who inhabit the earth 5000 years from now are going to have a chance to look back through the centuries and see just how we ran our industries and manufactured our products in the year 1924. And they won’t have to decipher inscriptions, nor make conjectures to learn how far their civilization has pro- gressed. They will see us in the movies! The possibility that motion pictures of 1924 workmanship can be handed down through the ages comes through the work of Watterson R. Rothhacker of Chicago, Ill., who has developed a_ preserving process to the point where he is ready to store—in the Smithsonian Institution at Washington, D. C.—history’s first collec- tion of movie films. The films will be sealed in a preserving vault, with a stipu- lation by Mr. Rothhacker that it remain sealed for 5000 years. Scenes from rolling mills, steel mills, engine factories, and machine shops will be included in the collection.

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2ce in ch, ich ich for tht ast ils. ep ht, act 100 2 a ies nd ar 1er ro- Hudson Maxim Still Young and Vigorous at 71 | gute from whitening his patriarchal hair and beard, and thickening a little more his stocky frame, old age has left few marks on Hudson Maxim, famous inventor of explosives. At 71, he punches the bag and pulls the weights like a youngster training against the day when he may topple a champion. Vigorous, sound of body, and in love with life more than ever, he con- tradicts the theory that men who cram each day with activity and achievement thereby shorten their lives. At his beautiful home on Lake Hopat- cong, N. J., with his wife, he has settled Hudson Maxim at his daily exercise down to enjoy the rest of life. Respon- sibilities thrown aside, he does whatever he wants to, with the zest of a boy suddenly showered with good things, but with the keener enjoyment of one who has struggled for them. Genial and young-spirited, he is the idol of the neighborhood children. Each year he takes delight in playing the part of King Neptune in the Atlantic City beauty contest. He also enjoys mental combat over a chessboard. THROUGH its destruction of cotton, the boll weevil’s bill to the average American family is $50 a year, and there is little prospect of cutting down this loss, says W. E. Hinds, of the Alabama Experiment Station. POPULAR SCIENCE MONTHLY 59 Edison’s Birthplace Discards the Oil Lamp HE little brick house in the village of Milan, Ohio, in which Thomas A. Edison was born 77 years ago, recently was lighted by electricity for the first time. For a century the kerosene lamp, driven from nearly every American home by the great electrical wizard, has held full sway. The house is owned by Mr. Edison and is occupied by a relative of his. Midget Engine Drives Model Speed Boat FOUR-CYLINDER, 43-ounce steam engine, generating one-quarter horse- power at 3500 revolutions a minute, drives the 42-inch model boat shown below at the remarkable speed of from 10 to 12 miles an hour. Boat and engine are the work of Horace E. Boucher, of New York City. The tiny craft is built stoutly of three- ply birch veneer, mahogany-trimmed. She has twin screws, and racing lines modeled after some of the world’s fastest boats. She is 42 inches over all, with a beam of 934 inches and a draft of 514 inches. The maker also has perfected single- and double-cylinder midget engines. The former weighs 10 ounces and the latter 32 ounces. When either of these is used, only a single screw drives the craft. The boiler for the four-cylinder engine is tested to 250 pounds pressure and the safety valve is set to blow off at 80 pounds. The bore and stroke are 34 by 34 and the engine is 814 inches long. Horace E. Boucher with his 42-inch steam-driven boat. Above: Midget steam engines

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60 POPULAR SCIENCE MONTHLY Unsinkable Life Raft Serves as a Duck Blind When afloat, the duck blind draws water up to the shelf holding the decoys OMPACT and comfortable, this com- bination duck blind and life raft, in- vented by Dr. Charles Hunt, of Washing- ton, D. C., enables a hunter to make easy use of the most favorable locations, re- quiring only a tow there and a tow back. It cannot sink or capsize, its designer claims. Resting on a seat inside, the hunter can wait in comfort for his game, while about his odd craft, tethered by strings, floats his flock of decoys. The raft floats at the level of the circular shelf, upon which the decoys are shown. A small heater can be carried inside. An Ocean Sulphur Spring UBBLING out of the ocean from a depth of 125 feet, a big spring of fresh sulphur water, two miles off the coast of Florida, near St. Augustine, recently was surveyed by experts of the U. S. Coast and Geodetic Survey. The government scientists anchored directly over the troubled waters of the sea spring. The water sampled was about the same temperature as the surrounding Atlantic, but the tremendous size and force of its geyser-like upwelling was plainly apparent at the surface. An Automatic Landing Net for Fishermen NE of the handy new inventions for the fishing season is a collapsible, automatic landing net that folds in a compact case. When inches in diameter and weighs but 13 ounces. When open, it is 12 inches long and 91% inches wide. not in use, the fisher- man can hang it on his belt, where it is instantly available. Simply pressing a button on the case causes the net to spring out and open. It can be folded in 10 seconds. A portion of the hoop opposite the handle folds in and the netting is wrapped about the two parts ‘ thus formed. Folded, the net is 13 inches long, 1% Wrapping the net on the frame The net ready for use Limb of Spruce Indicates Changes in Weather : a SD | A PEELED spruce limb, attached to the door of an office in the U. S. Forest Service’s Forest Products Labora- tory at Madison, Wis., indicates humidity changes with very nearly the accuracy of a scientific instru- ment. During the months when artificial heat is used, it bends far to the left. During the warmer months, when the win- dows are open and the air of the room is moister, it be- comes nearly upright. These changes cause its tip to move through a distance of 30 inches, describing an are of about 80 degrees. Dates indicated on a chart along this are show its position at different times of the year. This remarkable action arises from the presence of compression \wood along what originally was its under side. Com- pression wood is found on the under side of limbs and on the lower side of leaning trunns of all cone-producing treesa It is the action of this wood that causes the limbs of standing dead trees to curve down during protracted dry weather. Moist weather swells the compression wood, straightening the limbs. The weather indicator The electric converted into a gasoline car showing con- cealed radiator (at left) Electric Car Now Uses Gas ‘7HEN an electric automobile, prac- tically new, was condemned to the junkman recently because of the cost of batteries, an inventive mechanic in a southern Minnesota city conceived the idea of replacing the electric motor with a gasoline motor from a small, popular- priced automobile. The result is said to be entirely satisfactory. The frame and differential of the orig- inal electric were used. The steering lever was not changed. Although the car weighs 2300 pounds, the engine drives it easily, at a speed of from eight to 35 miles an heur.

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Se ES Aw yo 1e 2S by) New Garden Tool Performs Three Operations WEEDER, a mulcher, and a culti- vator are combined in a new hand- pushed garden implement resembling a lawnmower in appearance and operation. Its triple function and therapidity with which it works are said to lessen labor greatly. Eight blades, set in revolving reel heads, re- volve against a Sima on ar y knife. This knife, slightly behind the blades, travels just below the surface of the soil, cutting the weeds at their roots. The revolving blades destroy any weeds that escape, pulverize the clods, and aerate the soil. Between the blades and the knife is a five-eighth-inch space. The granulated top crust pours evenly over the knife through this, leaving a level mulch. The cultivator attachment need not be used when only shallow cultivation is de- sired. When not in use, it rides on top. Weeder and cultivator Collapsible Coat-Hangers Fit in Pocket Case S™ of these new collapsible nickel- plated coat-hangers, in a small leather case, can be carried in a man’s hip pocket. Cases containing one, two, three, or four hangers also are available. They are especially useful for travelers and camp- ers. Closed, each hanger measures 23, inches by three-quarters of an inch. Each has a 16-inch spread when expanded. The hanger collapses by telescoping. The telescoped arms then fold within a two-sided frame. A second frame then folds, closing the other two sides of the first frame and locking the telescoped arms in place. The illustration shows how the hanger telescopes, folds, and fits in the small, neat leatheroid case. POPULAR SCIENCE MONTHLY 61 This Sailor Makes the Wind Saw His Wood Louis Brotten, 86 years old, cutting wood at the windmill saw he invented and constructed FTER years at sea, many of them on sailing-ships, coaxing lazy winds, Louis Brotten, of Bay Farm Island, near Alameda, Calif., finds it a simple task to make the winds saw his wood. At the age of 86, he earns his living by turning the breezes to work, standing before his windmill saw whenever and as long as a stout enough blow is on. The saw is his own invention. He built the machinery himself, working out the right angle for the vanes. A belt from the windmill shaft runs the saw. What Goes Up the Chimney VERY time a ton of coal is burned in the family furnace, 17 tons of gas go up the chimney. Of these tons, 16 are gases of the atmosphere. More than 12 are of nitrogen. Nearly four tons of oxy- gen used in burning the coal go up as earbon dioxid, sulphur dioxid, and water vapor. Most of the coal—about 1500 pounds or so—also goes up the chimney as carbon dioxid. Less than one part in 100 forms smoke. A Handy New Tool for Opening Wrappers PENING the wrapper of a magazine without tearing the magazine has been facilitated by the invention of an ingenious cutter, approved by the United States Post Office Department. The device also handily cuts string on packages. The too! has a curved blade with a thin, flattened tip. The latter is inserted under the wrapper, slitting it up neatly. The handle is a sort of hook, that enables the user to keep the blade quite flat against the magazine or pack- age. ——— The cutter is the invention of Arthur Hoffman, a rural mail-carrier Side and top views of the wrapper cutter, showing the blade of Howard, Neb.

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62 POPULAR SCIENCE MONTHLY World’s Greatest Powder Blast Tears Away a Hillside Sa The explosion. Half a million tons of rock shot upward and scattered over 40,000 square yards of ground. At the right is shown the great hole torn in the hillside by the force of the blast, which was one of the largest blasting charges ever set off Above: The 275-foot hillside near Lakeside, Utah, before the great blast was set off. More than 150 tons of spe- cial) powder was used ORE than 150 tons of especially M powerful blasting powder, said to be the largest charge ever set off for commercial purposes, recently tore away a hill 275 feet high with a 1000-foot face, near Lakeside, Utah. More than a half million tons of rock shot upward with a mighty roar and scattered over 40,000 square yards of ground. The entire population of Lakeside joined with railroad and blasting engi- neers from all parts of the country in wit- nessing the spectacle from a hillside more than a mile away. Seven months were required to prepare the hill for the great blast, which was set off by the Southern Pacific Railroad to obtain rock for building up the fills ap- proaching the company’s trestle across the Great Salt Lake. More than enough material for the entire construction work was obtained from the hill. Six tunnels, each from 100 to 150 feet deep, aggregating 4100 feet in length, were bored. These were loaded with the 150 tons of special powder, said to be as powerful as 250 tons of ordinary blasting powder. Monoplane with Revolving Wings Designed to Fly Straight Upward a monoplane, and acting as one, except when vertical flight is de- sired, has been invented by Russell Hal- ligan, of Beardstown, IIl. The machine, which so far exists only A. HELICOPTER closely resembling The view of the model helicopter-monoplane at the right shows the wings set for gliding flight. Below, the wings have been swung halfway around on the drum like a propeller as a model, is designed on the following principles: The wings are attached to the fuselage by means of a drum that allows them to revolve. -The under surface of the left wing is constructed to allow the forward edge to be lowered by controls in the cock- pit. Thus the pitch of the left wing can be altered, causing the wings to become a large propeller. The motors, in the wings, drive two propellers, one on the forward edge of each wing. Since the motor in the left wing can be reversed, these two propellers cause the wings to revolve. When they revolve at a speed sufficient to counteract the air resist nce on the wings, the plane, it ‘is claimed, will rise vertically, in the manner of a helicopter. When the desired height is reached, the wings will be locked in a monoplane posi- tion by a contracting brake on the drum. The pitch of the left wing then will be re- stored to normal, and the left motor again reversed. The plane then will be sent into a glide, to gather speed. When a flying speed has been attained by this means and by the propellers, the plane will fly as does any monoplane, the inventor asserts. In landing, these operations would be reversed. | ——— A = TH —_ Ww ms f. G, _ =. 2 2c 2 Ge oa A. eee

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wo ich ing ers ley act ne, the the OSi- mm. ain nto ing ans yas rts. be POPULAR SCIENCE MONTHLY 63 Eth 3g FORDSON tractor is said to deliver twice its usual power at the drawbar when the wheels are shod with a pair of newly invented continuous-tread crawlers. This increased power results, it is claimed, from a change in gear ratio and the elimi- This Fishing Engine Pulls in the Big Ones 9 potent in halibut by hand. is a difficult job, even for a Gloucester fisherman. For this reason a fishing en- gine recently has been invented to do the heavy work of bringing a 25-pound, struggling fish, a heavy deep-sea lead, and many fathoms of wet line over the side without any muscular effort. The device is driven by a belt from the propeller shaft of the boat. As the fishline comes over the gunwale, it first passes through two rolls that prevent it from tangling, around a winding wheel, and then between two smooth gripes held together by a tension spring. Varying the tension of this spring makes the machine pull strongly or lightly, as is desired, so that it can be used to catch anything from cod to a young shark. A revolving line-tub keeps the fishline from becoming snarled. All the fisherman has to do when he feels a bite is to start the engine. Odd “Crawlers” Invented to Dou ear nation of the old waster, traction slippage. Since 1000 square inches of traction area is in contact with the ground at all times, the pressure of the tractor upon the ground is said to be only 3 14 pounds to the square inch, far less than the pressure of a horse’s hoof. Thus a tractor equipped with the new treads is built to operate on ground so soft that neither horses nor tractors with ordinary wheels could work it. In field tests the invention is said to have enabled a tractor to pull three 14- inch plows, at a depth of 71% inches, over a footing so poor that an ordinary ble a Tractor’s Pulling Power tractor barely could pull two such plows. The control is unique. Square turning, without strain on the differential, is made possible by two independent clutches. The clutch on the inside track is released, while the other remains engaged. Thus the inside track stands still while the outer one moves at normal speed, not at double speed as it would if working through the differential. A liberal range of up-and-down track oscillation permits riding over rough ground without losing traction efficiency or throwing undue strain on the tractor frame. Divers Now Can Telephone from the Depths ORDS transmitted not by the voice itself but by external movements of the throat now are being used by divers to communicate over a telephone line with those above. An ordinary microphone allows the diver to hear from above, but heretofore, communication by a diver, except by pulls on the life line, has been next to im- The trans- mitting de- vice in posi- tion about the throat. Below, the receiving ap- paratus above water possible. Noises produced by the pump- ing of air to him have drowned his voice. Yet such communication always is desir- able and often vital to his safety. The new device, the “laryngaphone,”’ is held in tight contact with his throat, as shown in the photograph. Thus every throat movement, as transmitted to those above, is transformed into the sounds of a voice, reproduced with perfect clearness, yet unaffected by the noise of pumping operations. AT THE highest point reached by man, about 614 miles, the air pressure is less than a fourth of what it is on earth, and the average temperature is 50 degrees below zero.

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POPULAR SCIENCE MONTHLY AUXILIARY PLATFORMS Above: The giant walking excavator, showing one of the platform ‘‘feet’’ and its attachment through acam. At left: The walking mechanism. The ‘‘feet’’ are raised and lowered by cams actuated by a shaft Walking Excavator Hikes 30 Feet a Minute HIS giant excavator walks—walks up and down steep grades, over rough ground, and around obstructions. It will walk about three miles in 10 hours, its builders claim, consuming 45 gallons of gasoline or distillate and less than two gallons of oil. It covers 30 feet a minute and is operated by one man, with one lever. The remarkable machine is said to be revolutionizing methods of constructing drainage canals and levees, enormously reducing costs, and opening projects hitherto not considered feasible. With a gang of four or five men, it is claimed to do the work of hundreds of men with teams. The walking “‘feet’’ of the machine are two auxiliary platforms, one on each side, acting through ingenious cams. When the machine is to walk, a pinion clutch is engaged and the engine started, setting a camshaft in rotation. As this revolves, the cams lift the auxiliary plat- forms and swing them forward until they again are returned to the ground by the cam movement. As the shaft continues to rotate and while the platforms are in contact with the ground, the cams slide along the tread plates on the tops of the auxiliary plat- forms. Thus the rear end of the machine gradually is raised from the ground. Finally, the cams come in contact with stop blocks on the platforms. They cease sliding and move the machine forward, lowering it to the ground. The excavator rests upon a large flat base while working, reducing vibration. VERY day your actions are affected by your knowledge of | scientific facts. You avoid drafts because you know they cause colds. You avoid live wires because you know they are dan- gerous. But once you knew neither of these facts. Similarly, you still have hundreds of vital facts to learn, facts that will help you guard yourself, enable you to . Is our hair alive? — SOCHNIDA UE WN found on earth? How Much Science Do You Know? recognize opportunities, and save you wasted effort. Some will help in small matters, some in great matters. The answers to five of the 12 questions below offer you useful facts of this kind. Which questions are they? The correct answers to all the ques- tions appear on page 134. But don’t look until you’ve tested your knowledge first by trying to answer them yourself. Could a balloon keep on going up forever? Why do not ferns grow well in the house? Why do cats’ eyes shine in the dark? How many stars can we see? Do dreams ever foretell the future? What is the function of the liver? Why is salt mixed with ice in an ice-cream freezer? How was the age of the earth determined? What gas was discovered in the sun before it was 11. Why does chloroform produce unconsciousness? 12. Why do solids melt when they get more than so hot? ~ ry rr CF. ft iz é A Light Cultivator for the Small Garden ee star-pointed disks of the easily operated hand implement for the gar- den, shown below, are designed to break up cloddy soil. A transverse blade just behind them, slightly below the surface of the soil, pulverizes and levels the soil they break, and cuts off weeds. The narrow strip of soil worked by the tool—7 14 inches—allows use of the tool . le A woman operates the cultivator easily where the rows or plants are very close together. It is said to be particularly useful after a rain, when the top soil is crusty, and in preparing a seed bed. Because of its ease of operation, the new tool is said to be especially useful for women gardeners. Invisible Mirrors Reveal Secrets of Nature LL about us, everywhere, are count- less numbers of hidden mirrors; some are invisible to the unaided eye; others are larger than our earth, and still others are so small as to be ordinarily in- visible through high-power microscopes. All these mirrors become visible by re- flected light. In an evenly illuminated room, one sees nothing in the air; but if this same room is darkened and a ray of sunlight shines across the room, a cloud of dust particles is visible in the beam of light. These dust particles act as minia- ture mirrors and reflect light. The moon and the planets are visible to us only when they reflect light shining on them from our sun. Scientists use this principle in examination of the most minute particles and microorganisms, which ordinarily are invisible through the microscope. Objects are placed ona black background and illuminated from the side. Submicroscopic particles are then seen brilliantly lighted against the dark surface, because they reflect the side rays of light to the eye.

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ose irly 1 is the oful int- Ors; ve; still in- es. re- ited it if y of oud n of nia- e to yon this nost sms, the lack the shen lark rays Walking Radio Receiver Entertains at Fair PERAMBULATING radio receiv- ing set entertained the visitors at a recent fair in Leipzig, Germany. The complete set, including an aerial and a loudspeaker, was carried about attached to the shoulders and chest of a man. The loop aerial and loudspeaker were mounted on a frame slung from shoulder straps like a knapsack, while the receiving instrument was hung from straps about the operator’s neck. Entertaining street crowds with radio POPULAR SCIENCE MONTHLY New Receiver Safeguards the Morning Milk agp nehaleat aioe of the morning milk from doorstep hazards such as thieves, freezing weather, and roving dogs, is the aim of the ingenious English invention pictured here. The milkman pulls a knob on the out- side of the kitchen door or wall, exposing an opening at the end of a tube leading inside. Into this opening he pours the milk, which runs into an indoor container. Automatic Secretary OUR telephone instrument can be transformed into a mechanical secre- tary, it is claimed, by a new instrument designed to record calls arriving in your absence, or to transmit automatically a message dictated for some one you expect to call while you are away. This is accom- plished by a novel use of talking-machine records. As many as 12 telephone calls can be recorded, the inventor asserts, but only one message can be left for transmission. 65 Records Phone Calls For either use, the telephone receiver is re- moved from the hook and placed over a contact opening in the box housing the mechanism. A clip keeps the receiver arm down. The mechanism is connected with the bell sounder, which, by ringing, releases the hook. Two buttons, one controlling the re- ceiving record and one to be pressed be- fore dictating the message to be trans- mitted, are on top of the box. By pressing the former button, the receiver having been returned to the re- ceiver arm of the tele- Recent Publications | A résume of new books on science and invention How to Build Your Radio Receiver, edited by Kendall Banning and L. M. Cockaday. A comprehensive, non-tech- nical book, giving detailed, specific in- structions regarding the construction of seven types of radio receivers, ranging from a simple crystal set to the regenera- tive superheterodyne. Illustrated. Pop- ular Radio, Ine. The Problems of the Obelisks, by R. Engelbach, chief inspector of antiquities, Upper Egypt. An interesting popular exposition of engineering feats accom- plished by the ancient Egyptians. Illus- trated. George H. Doran Company. The American Home Diet, by E. V. McCollum and Nina Simmonds, of Johns Hopkins University. Eighth edition. What to eat and why, including a scientific menu for every day in the year. Frederick C. Mathews Company. Hearing, by Robert Morris Ogden, pro- fessor of education, Cornell University. A discussion of acoustics ftom the physio- logical and _ psychological standpoint. Illustrated. Harcourt, Brace Company. Wood-Carving, by J. C. S. Brough. A practical handbook of ‘“‘The Woodworker Series.” J. B. Lippincott Company. Above: Dictating a message to be transmitted by the automatic recording secretary to an- other party. At the right, the apparatus is shown in adjustment to receive and record incoming calls. Ringing of the phone bell automatically releases the receiver hook phone, the listener can hear one of the messages" received, the particular one depending on which is indicated by the pointer of a dial at the end of the box. Another dial, below this one, is a memorandum of the unused records.

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PS - 3 © pe age Rat ST ee Persistent cultivating and weeding are the first requisites for a successful garden. The handy tool shown above does It can be adjusted to a four- to 10-inch spread both. By Ernest Bade, Ph.D. S WITH most other activities, so A with gardening—a good beginning is most important. Inthe March issue of POPULAR SCIENCE MONTHLY I told how to plan and plant your garden. Yet, so far as your garden is concerned, well begun is not half done. A garden requires regular, systematic, intelligent care from planting time to the harvest. Many elements—even Nature itself—conspire to place obstacles before the home gardener, and try to prevent his success. And so, once the tiny shoots have begun to show themselves above the ground, bringing your growing plants to maturity becomes a game—as fascinating and engrossing as any you have tried—in which you play a lone hand against a combination of alert and unscrupulous opponents, with your plants as the stakes. The first adversaries you are likely to encounter are weeds. Weeds are mysteri- ous, stealthy, greedy intruders. Where they come from no one knows. But we do know that virtually all weeds thrive only in cultivated ground under the protection of the plants you are trying to grow. Their Making a paper cylinder to protect the young plant from cutworms To insert the cylinder, first dig a trench around the POPULAR SCIENCE MONTHLY A Fascinating The common potato bug hungry roots steal from the soil the nourishment your plants require. Some live on the very tissues of the cul- tivated plants. Others bring with them injurious insect pests and fungous dis- eases. All of them take away light, air, heat, and moisture from the soil. And, unless they are removed as unceremoniously as they have come, they will ruin your garden. The simplest, safest, and surest way of removing weeds is to pull them up by the roots. You may, though, use a hoe, or a culti- vator, or weeder. If you use tools, be sure to dig under the roots, for you will have trouble enough getting rid of the weeds that will follow those you remove, without leaving roots in the ground to sprout anew. Don’t defer weeding until your garden is choked. A little neglect in this regard may offset all the care you have taken with your garden previously. N ONE respect, Nature made a wise provision in causing weeds to spring up in cultivated lands. The necessity for removing weeds causes many a gardener to give to his beds attention they would not receive otherwise, and helps him in contending with another persistent enemy —surface crust. After every rain and every watering, a hard crust forms on the surface of the ground. It makes future waterings all but useless, since the water merely runs off the surface without penetrating. It also pre- vents air from getting to the roots. Now, although weeding will break up this crust to some extent, I shouldn’t ad- Next, set the the trench and replace the soi plant cylinder in Your GARDEN Game which You Can Above: A tomato caterpillar coated with cocoons of parasitic wasps that, hatched, kill other caterpillars Destructive flea beetle vise you to depend on weeding entirely. Hoe your garden thoroughly at least once every two weeks. If you loosen the soil, it will retain moisture longer, and the yield of your garden will be that much greater. The watering of your garden is one of the most important features of its culti- vation, since it is through water that the plants absorb nourishment from the soil. Give your garden just enough water— neither too much nor too little. Cer- tainly you never should defer watering until the plants have begun to wilt. Neither should you keep the soil in your garden wet all the time. Too much water will weaken plants; too little will cause them to die. Cold water applied to a warm soil will stop the growth of plants. For this reason you never should water your garden while the sun is shining on it. Do it before sunrise or after sunset. About the time that the weeds begin to thwart your gardening operations, an- other army of dangerous opponents is likely to appear—insect pests. One of the most common of these is the flea beetle, a tiny, black insect, no larger than a pinhead. It acquires its name from thickened hind legs, which enable it to hop like a flea. This insect often destroys cabbages and cucumber vines. It thrives in dry, sunny soil, but is killed by moisture and damp- To transplant, first dig a hole for the plant with a trowel nes yor pla flo otk bee pot des sol: ars tal fro sol roc wo roc grc bo: oul the

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An rely. once vil, it yield ater. 1e of -ulti- t the soil. ter— Cer- ering wilt. your vater 2ause to a ants. water on it. rin to its is ne of flea than from it to s and unny amp- ole wel A_ swallow - tail caterpillar with eggs of trachina fly near head. The larvae de- stroy their host The cutworm pest ness. Ii the flea beetle visits your garden, you can get rid of it by watering the plants. Dusting the beds with ashes, flowers of sulphur, or tobacco dust are other ways of controlling its inroads. Leaf-eating insects—caterpillars and beetles of various sorts, of which the potato bug is the most common—can be destroyed by spraying the plants with a solution of three parts of crystallized arsenate of soda and seven parts of crys- tallized acetate of lead in water; between from one to five ounces of the chemical solution to two gallons of water. Then there are insects that attack the roots of the plants. The common cut- worm, which severs the plant from its roots just above the soil, is typical of this group. The best way to prevent these from attacking seedlings is by inclosing the plants in paper cylinders, six inches tall and about three inches in diameter, sunk in the ground to a depth of four inches, as shown in the illustrations at the bottom of these pages. Cutworms appear only at night. They can be killed. by wetting the ground thoroughly with warm water (about 100° F.). Insect enemies of another group destroy plants by introducing their beaks or pro- bosces into the plant tissues and sucking out the sap. Leaf lice, scale insects, and the tiny leaf hoppers and bugs belong to The next step is to place the plant in the prepared hole With the soil replaced, make a slight depression around plant POPULAR SCIENCE MONTHLY in the SUMMER Play in Your Own Back Yard Root-destroying cabbage fly this class. A spray with oil for a basis supplies the best method of contending with these pests, for the oil spreads over their bodies, closing their breathing pores, which are on the side of the abdomen, and suffo- cating them. There is an admirable spray for this purpose that 67 gardeners call ‘“‘soap emul- sion.’’ Itis prepared by dis- solving two ounces of soap in boiling water, adding a quart of kerosene, and shaking. This stock solution is diluted with from nine to 20 parts of water, depending on whether the insects to be attacked are scaly or soft-bodied. When spraying, wet the leaves and twigs, but not so thor- oughly that they drip. Do not permit the solution to collect in puddles on the ground, for it is harmful to the plants if absorbed by them through the soil. Plant diseases are of many sorts, and are persistent enemies of the home gardener and the professional farmer alike. Diagnosis of the disease is essential before it can be cured. I should advise the amateur gardener not to attempt to treat his infected plants until he has consulted an expert; otherwise you may do more harm than good. 7 GET the largest possible yield from a small garden, as I explained in my previous article, beds from which early vegetables are gathered should be dug up immediately and planted with late vege- tables. Winter cabbage, lettuce, or en- dives can be sown profitably in the beds from which the early vegetables are har- vested. Better, they can be transplanted Now pour water into the de- pression to moisten the roots In combatting insect enemies such as the tiny leaf hoppers, leaf lice, and bugs, which suck the sap from growing plants, the most effective weapon is the spray, applied as above to the beds after being sown in seed beds. Transplanting is done best at twilight. After the plants are placed in the ground, they should be well watered, and on the following day they should be kept shaded from the rays of the sun. Placing a small fruit basket over the plant is the best way of accomplishing this. NE final warning: gardening is a fas- cinating amusement, but growing a successful garden entails a_ certain amount of work. Don’t let your enthu- siasm lag. This is likely to happen when the weeds begin to show. Success in gardening is well worth working for. The physical work in the open air is bound to do you good, and there isa thrill and satisfaction in harvesting good vege- tables, grown by your own care and pa- tience, that will more than repay you for all the trouble and work you devote to them during your spare hours. VERY reader of POPULAR SCIENCE MONTHLY who enjoys making things with simple tools will be inter- ested in a page of remarkable pictures of ingenious homemade oddities, to appear in next month’s issue. Finally, cover the transplant with a basket to shade it

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An Ideal Portable Radio Receiver —And How to Build It Yourself By Joseph Calcaterra Radio Editor of PopuLar ScrENCE MONTHLY casting stations, the perfection of more sensitive receiving sets and the reduction of interference between stations are combining this summer to make radio more popular than ever as an outdoor sport for vacationists everywhere. Wherever you may be taking your outing—in the mountains, at the lake or seashore—radio as [ ‘eastine sta power of radio broad- POPULAR SCIENCE MONTHLY without the A bat- tery, is 20 pounds. The panel is 18 by 4 inches and was cut from a standard 18 by 7 inch panel. While best results are obtained with the six-volt tubes, developed today is able to bring to you from afar the daily programs of news and _ enter- tainment. Even in a simple single- tube receiver, as Jack Binns points out in another ar- ticle in this issue, there is a good store of vacation fun, even though it cannot bring you the best that broadcast radio offers. For the man who is eager for the best possible re- ception during his summer outing, I shall describe this month how to con- struct what I believe is an ideal portable set—a powerful four-tube reficx receiver carried in a light suitcase, yet practically equal in results to a six-tube set. HE circuit calls for one stage of trans- former-coupled radio-frequency am- plification; a reflex stage equal to another stage of radio-frequency amplification; one stage of audio amplification, with a crystal detector for detection; two stages of straight audio-frequency amplification equivalent to two stages of radio-fre- quency amplification, and, finelly, three stages of audio-frequency amplification. The novel feature of this circuit lies in the fact that, if desired, the circuit can be changed easily to one having one stage of trans- former-coupled radio- frequency amplifica- tion, a vacuum-tube detector, and two Layout of parts for the portable four-tube reflex receiver. The parts are lettered and numbered to correspond with the wiring dia- the smaller tubes can be used to advan- tage. When the set is used as part of the auto-camping equipment, it is a comparatively simple matter to carry along an extra storage battery or even to use the storage battery of the automobile when the car is not running. If four of the tubes consuming .25 am- pere at six volts are used, an 80 ampere- hour battery is sufficient for approxi- mately 80 hours without recharging. This will carry you through a two weeks’ va- cation. Using the set shown on this page, with a two-foot loop, I brought in local gram below. The upper illustration shows how this compact but sensitive receiver can be car- ried and operated in a suitcase on the auto trip stations with prac- tically the same volume as was ob- tained with a standard three- tube outfit using a good outside aerial. With an _ outside aerial, and operat- ing all four tubes, I received pro- grams too loud for comfort in a large room. The first two tubes alone with the loud- speaker plugged in on the first jack were sufficient to fill the room. In the wiring diagram at the bottom of the page the symbols and terminals have been marked to correspond with the numbers indicating the respective parts in the panel layout. This makes it easy to follow the connections between the various parts. UMBERS 1 and 2 are the aerial and ground posts respectively. Num- ber 3 is the aerial inductance switch, while No. 5 is the ground or grid circuit switch. Number 4 is the tuning coil, consisting of 60 turns of No. 22 d.s.c. wire wound on a tube three inches in diameter and three inches long. The top of the winding is started one quarter inch from the top of the tube. Taps are taken at every 10 turns. The taps are arranged in a straight line down the coil so that they will be close stages of straight audio- frequency amplifica- tion. The complete set, including phones, B battery and CONTACT to the switch points of both switches. space for tubes, can be built into a suitcase 22 inches long, 12 9 inches wide, and 6 4 inches deep. eee The total weight of the outfit, > Number 6 is a 23- plate variable con- denser with Vernier feature. Number 7 is a standard potentiometer Wiring diagram of the portable set, with parts let- tered and numbered to correspond with layout above having a resistance ele- (Continued on page 131)

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rac- ame ; ob- a ree- nga rial. tside erat- ibes, pro- d for large first rlone oud- ed in jack ic tO iring the the have the parts easy - the 1erial Num- ritch, ircuit isting nd on three ‘op of arted from tube. every os are ‘aight 911 so close nts of a 23- con- ernier Tisa meter e ele- - 131) POPULAR SCIENCE MONTHLY 69 Radio by the Roadside How to Get the Most Vacation Pleasure By Jack Binns America’s Most PopularWriter on Radio AN I take my radio set with me on i my vacation, or on my auto- camping trip? This question is in the minds of many radio fans now that the annual outing season is upon us. The difficulty in deciding it lies in the widespread belief that a specially de- signed type of super- sensitive receiver must be used for this purpose, par- ticularly on an auto- mobile. As a matter of fact, any good radio receiver can bring endless enjoy- ment on a motor trip, provided you are careful to meet its requirements. Of course you cannot expect loud- speaking results on the same scale as when the receiver is operated in the home, any more than you can expect the same speed out of your automobile predicted that within five years all mov- ing vehicles will be equipped with radio. — With the equipment already available there is fun and profit enough for all of us who hit the motor trail to far-off places this summer. The only problem is how to make use of that equipment. And that brings us back to practical sugges- tions for a successful radio vacation. from Your Receiver in as straight a line as possible between its two temporary supports. A long, single strand usually is better than a number of short ones. The wire should be led straight to the receiver, and should not have any excess length lying around in a coil. Copper wire always should be used for the aerial. Of course, a stranded wire may be em- ployed, but it should consist of copper. The gage does not have to be as large as normally used, although it should be fairly strong. The temporary aerial can be carried conveniently on the trip simply by wind- ingitonafishingreel, or inside the cover of a large pocket tape-measure. If such a device is used for storing the aerial when not in use, not more than 150 feet of wire can be used. The best plan will be to run the automobile a sufficient distance on a bad country road that you get on a smooth-sur- faced thoroughfare. If you frankly re- cognize the limitations of your receiver, there is no reason why a radio vacation should not be a huge success. Indeed, it is the proved success of radio along the road, by the roadside, in the secluded camp, and by the seashore, that is open- ing possibilities of future communication so tremendous as to tax our imaginations. For the use and enjoyment of travelers everywhere—and especially for motorist and camper—there already have been developed radio receiving outfits so powerful and selective that they- can catch messages at night from across a continent, yet so compact that you can carry them in a small suitcase. The superheterodyne is one of these latest marvels. The portable four-tube reflex set, described by Joseph Calcaterra on the preceding page, is another—just a handbag that you can carry from room to room, or in your car from city to forest and, stream, from town to town, or from state to state. With the ever-increasing demand for this sort of radio enjoyment—radio on the road—how long will it be before you will be able to carry radio about in your pocket—radio in a little box about the size of a matchbox? Simply turn a little switch, and get in instant touch with the best thought, the best music and enter- tainment from far-off Australia or South Africa! Hiram P. Maxim, president of the American Radio Relay League, recently An effective way to enjoy radio while the car is traveling along the road. With a multiple aerial strung between supports attached to the front and rear of the car, this outfit in- apparatus. driver. And the main points to be considered are these: “What facilities shall I have for erecting an aerial, and, how far shall I be away from the nearest first class broadcasting stations?”’ OW, if your trip is to be an auto- 4‘ mobile outing, a tour from place to place, either according to a well laid out plan, or haphazardly, as the whim may seize you, it is inevitable that you will encounter widely varying conditions, so that the same arrangements for recep- tion will not answer the purpose through- out the trip. Consider the first of our two problems —the aerial. No matter where an auto- mobile trip may take you, nearly always you will find some object that will stand you in friendly stead as a mast upon which to hitch your aerial. It may be a tree, a pole, or even a rock perched on the top of a small hillock. Your own ingenuity will enable you to size up the local situation quickly. The top of the auto can be used for anchoring the other end of the aerial. Twenty years of practical experience have demonstrated that the use of a good clear aerial results in the best reception, so my advice to you is to take advantage of every local opportunity to erect one— irrespective of the sensitivity of the set that you intend to use. This improvised aerial can consist of a single wire stretched cludes a transmitting as well as a receiving Note the cabinet back of the It is the work of an amateur, J. M. Griebe of Richmond Hill, L. I. away from the tem- porary support, so that all of the slack is taken up. On the care with which you erect this aerial depends the entire success of radio reception in camp. When you have arrived at the spot where you wish to set up your receiver, the first thing to consider is the geographical location. Find out the direction of the nearest broadcasting station you wish to listen to. Then erect your aerial so that it points directly toward that station— that is, the free end of the aerial should be farther away from the station, and your set nearer to it. You then will be taking advantage of a peculiar directional effect that has been definitely established as existing in radio transmission. All these suggestions, of course, apply to the reception of programs when a halt has been made. Some motorists undoubt- edly will wish to attempt reception while the automobile actually is running along the road. This, of course, is entirely possible, provided the distance from a broadcasting station is not too great, and a really supersensitive set is used. ERE again a good aerial is preferable to a loop, provided the design and construction of the set permits the use of either. Naturally, the aerial that can be erected on top of an automobile cannot be as long or as efficient as one of a semi- permanent type between two widely separated supports. Yet a very effective one can be set up by stringing a con- tinuous wire in zigzag fashion between supports erected on the front and rear

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_ POPULAR SCIENCE MONTHLY ¢ es . F ° Se - ei PS eS , a : * wee ee — = ~ S - s Ry a . + eee aa ee ends of the car. The metal framework of the automobile can be used as a counter- poise ground. One serious drawback to operating a radio receiving set on an automobile while it is running lies in the fact that con- siderable interference will be experienced from the radiations emitted by the spark plugs of the motor, and in some cases a hum from the generator of the car. If the broadcasting station is not too far away, this interference will not be noticed, but on weak signals it Radio on the fishing trip—A complete receiving outfit installed on the banks of the Green River, near Seattle, Wash. happen, and loudspeaker operation is possible from stations tremendous dis- tances away. The possibility of hearing distant stations is entirely one of chance, however, and the radio vacation should not be planned on chance by any means. The precautions usually observed when a set is being installed in the home for permanent use are equally important on the vacation trip. We all know, for example, that it is intervenes between the broadcasting station and the receiving set. The moun- tains will act as a barrier. An ideal location for reception is beside a body of water. This strange fact toa certain extent accounts for the location of many of the high-powered wireless telegraph stations along our seacoasts. In some mountainous districts it is practically impossible to get away from a range of high land. The thing to do in such a case is to get as far will be annoying. ONSIDER now the second of the two points that govern the success or failure of the radio vacation—the question of distance. As I said before, if you frankly admit the limitations of your receiv- ing set, you will save a lot of embarrassment and worry dur- ing the trip. Roughly speak- ing, we may take the daylight range of the various types of receiver as our guide in this matter, remembering that the average reliable range of Class B broadcasting stations is only 150 miles. The most sensitive receiver known is the superheterodyne. In the daytime it will record the average broadcasting sta- tions on headphones at a distance of 250 miles, and with the most powerful broad- casting stations it will reproduce on a loudspeaker at 150 miles. The neutrodyne will give similar results over almost the same distances. Transformer - coupled radio-frequency sets including reflex receivers, invariably operate on a loop, and their average day- light distances will be about 150 miles for phones and 100 or slightly less for loudspeaker work. Regenerative receiv- ers of efficient construction and design will give daylight results in the same manner over approximate distances of 150 and 190 miles, provided a good aerial and ground are used. These figures do not apply to night reception. Here an entirely different condition exists and one of which we know very little. At night almost anything is likely to A radio-equipped sedan, with the aerial strung from front to rear and supported at the center by a pole very difficult indeed to receive programs inside a steel constructed building. The reason is that the steel girders, being grounded, act as a shield, absorbing the electromagnetic waves. In the city we meet this problem by employing a set that is extremely sensitive and very selec- tive, such as the superheterodyne and the neutrodyne of good design and construc- tion. IMILARLY, on a vacation trip, we must watch for conditions that may hamper clear reception. Remembering the difficulties of receiving inside a steel building, it would be folly to choose an outdoor location for reception where natural obstacles would duplicate the difficulties of such a building. For ex- ample, if you are in the mountains, it never will do to erect the aerial in a location where a huge mountain range away as possible from the hills, for the following reason: Electromagnetic waves act somewhat similarly to water waves. The main difference is that the former pervade the medium in which they travel, whereas water waves are sur- face waves. You often have observed the effect of an ob- struction on water waves. Im- mediately behind the obstruc- tion is a “pocket” of calm water and at the rear of this pocket the waves converge. HE same effect obtains with electromagnetic waves. A mountain range will absorb them and leave a ‘“‘pocket’’ just behind the barrier. But at a certain distance behind the mountains, it will be pos- sible to obtain good reception, because the waves that have not been absorbed will come together in the same manner that water waves do. Finally, what type of receiver is best for use on a motor trip? A satisfactory radio vacation is quite possible with a single-tube set of the re- generative or reflex type, provided a good aerial is used and head-phone reception only is desired. Much better results will be obtained with two stages of audio amplification. The best possible results will be ob- tained with a neutrodyne, a superhetero- dyne, or a powerful reflex receiver. EGINNING next month, POPULAR SCIENCE MONTHLY will publish in each issue a pictorial summary of up- to-the-minute developments in radio. Here’s an easy way for you to keep in step with the amazing progress of this fascinating new science. ~ & =~ | eS Oo aacwmwoevoauorcactd © ee ee a Le ee Ll lll ll lL

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ting yun- side toa tion less t is rom » do ; far nills, act rater ce is the avel, sur- have ob- Im- truc- calm this tains aves. ysorb ‘ket?’ But ehind pos- ytion, been same _ best quite 1e re- good ption s will audio e ob- etero- >-ULAR ish in »f up- radio. pep in f this POPULAR SCIENCE MONTHLY 71 America’s Fastest Growing Sport Motor Campers by the Million Enjoy Comforts along the Road By Leslie V. Spencer, M.E. ef HEN going motor-camping,’”’ said an automobile writer in an article published 15 years ago, ‘‘take along plenty of extra tubes. It is not necessary, however, to load the car down with more than two extra cas- ings, because one is never more than two or three days from a town where the or- dinary sizes of tires can be obtained.’ Imagine that! ‘Never more than two or three days from a town where the ordinary sizes of tires can be obtained.”’ Yet, less than a score of years back, it was all too true. Motor-touring was not with- out its uncertainties then, and before 1910 it was prac- tically never attempted, be- cause of the hazards involved. In those days an au- tomobile hardly could be ex- pected to stand up under the strain of from 300 to 500 miles of country going. The condition of the roads made protracted trips hazardous. Indeed, whenever a group of hardy souls did venture forth to conquer the wagon roads of the day, they did so only after they had prepared for the journey for weeks in 2 ee on marked, are taken for granted, as are public camping-grounds along many of the more important highways. In fact, the motor-camping trip in summer has become the emancipator of thousands of American families of modest means—the outdoor sport of the multi- tudes. A year ago 1,250,000 men, women, and children took an active part in it; and this summer it is estimated that the number of happy motor gypsies will be increased to nearly 2,000,000. facturers add camp-car bodies to their standard lines. Automobile camping is confined to no particular locality or climate. More than 2000 cities and towns in the United States have established public camping- grounds for the accommodation of tour- ists. The average size of the municipal camp-site is such as to afford ample room for about 50 cars, although some are very much larger than this. Most public camping-grounds supply the campers with free fire- wood, electric light, water and laundry facilities, bath arrangements, toilets and re- fuse disposal. Some of the more completely equipped camps even have gasoline- and oil-supply stations, dining-rooms and kitchens, dormitories, dance pa- vilions, playgrounds, outdoor tables and benches, wooden tent floors and other enticing features. VERLAND PARK, at Denver, Colo., the larg- est public camping-place in the United States, is a strik- ing example of what some of our larger cities are doing to encourage motor tourists. With very complete facilities, advance. And, when finally under way, their car looked like a small moving-van, with spades, block and tackles, cans, ropes, tents and tent poles, trunks and junk draped all over the car. The unlucky riders in the back seat had to fit them- selves in with a heterogeneous collection of everything and anything that had even the remotest relation to the long-heralded camping jaunt in hand. The popular summer sport of motor- camping as it is known today is a de- velopment of the last half a dozen years. It has been called the fastest growing sport in the world. This summer the Easterner can trek from New York to the Golden Gate, and the Westerner from California to Boston, within a reasonably short time and think little of the feat. Well-built roads, plainly The motor tour of 15 years ago—a hazardous adventure in a car crowded and draped with unwieldy luggage and tires The beauty of the sport—and a feature that probably accounts largely for its in- creasing popularity—lies in the fact that the family with a $300 or $400 car can travel just as far and have just as much fun as the family with the most expensive limousine, HE awakening of automobile makers to the possibilities of this new every- man’s sport is evidenced by the fact that several builders of low-priced cars have been offering complete vehicles adaptable to the use of motor gypsies. A few local dealers, too, are offering specially built bodies suitable for camping. I con- fidently believe that within a few years we are going to see many car manu- this camp affords accommo- dation for 1000 cars. The tract is beautifully wooded, and it cost the city $250,000. Last year more than 60,000 motorists availed themselves of its privileges. Motor-campers do their summer vaca- tioning in one of these four ways: Some pack everything into a touring-car or sedan and make and break camp at each stop. Others tow a trailer that carries all the camping paraphernalia. Still another group does a more pretentious job of it by hauling a completely equipped camping-car trailer containing beds and dining accommodations. The fourth class buys a special camping-car fitted to almost any standard chassis. This last is the de luxe way of gypsying, of course, and involves considerable expense, for as yet there is very little standardization of Part of a mile of tourist tents in the world’s largest public camping-place—Overland Park, Denver, Colo. \W al a a ye i= gS ¢ rf é y St ‘ is it} re , ie Se ri Se. ee eo a 3 *% v7 fei Sixty thousand motorists camped here last year. Other cities have provided similar parks to accommodate some of the 2,000,000 motor-campers this summer

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72 self-contained camp- ing-cars. By far the greatest number fol- low the first method. The two impor- tant essentials to this kind of wander- ing outdoor life are eating and sleeping, and to these neces- sities the makers of auto-camping equip- ment have devoted their thought and ingenuity. ONE are the days of the pup tent. Your motor- camper now de- mands a_ specially constructed motor- camping tent or a set of beds under even a more sub- stantial roof than canvas can offer. Motor bungalows on wheels that possess every convenience for the night’s rest, are available at considerable expense, but the dyed-in-the-wool camper usually prefers canvas. Tents are of many and varied types, ranging from the lean-to supported by the top of the motor-car to the full-grown motor bungalow tent with comfortable accommodations for four or more. Most motor tents are arranged to collapse into very small packages, having folding metal braces and uprights, and folding into bundles small enough to be carried on runningboards. The specifications of one tentmaker’s prize package are before me. They make it clear that you are afforded a big double bed. with springs and mattress rivaling Most of the conveniences of home are pro- vided by this campers’ mounted on a small trailer. POPULAR SCIENCE MONTHLY folding bungalow It contains two kitchenette, icebox, in comfort your best box-spring bed. The bundle also disgorges a big, roomy, well- ventilated tent that requires no poles to erect—a real house, with screened and curtained windows. The specifications say further that the whole outfit with its aluminum-frame bed rolls into a pack- age only four teet long and 11 inches thick. HERE’S development for you! Think of that, and then consider the trouble it meant to carry the unwieldy tents of a few years back. Then, if you got the whole works into a full wagon bed, you were lucky. Another clever outfit on the market full-size beds with springs and mattresses, water closets, and several folding chairs and tables is called a ‘‘sleeping pocket’”’—a _ _ pneu- matic mattress and envelope arrange- ment with a flap at the top. The outer material is water- proof, and when you crawl into this co- coon and pull down the flap, you are snug as the pro- verbial bug in the rug. Also you are protected from in- sects. Many campers sleep in their cars on some form of swing- ing mattress fasten- ed at back and front above the seats. If the car is a closed type, such a bed offers all the comforts of home. About a score of concerns now. are tank, supply making camping trailers. When ready for the road, the newest trailer outfit is most compact, folding into a size not much larger than a pusheart. Opened up, it provides a temporary home for from four to six per- sons. Many of the models have elaborate cooking and dining facilities, folding tables and chairs, full-length clothes- closets, and tanks for hot and cold water. The days are vanishing when the motor-camper depended on wood fires. Now he usually carries a compact and convenient oil or wood burner that elimi- nates the digging of pits and the build- ing of ovens. When it comes to cooking utensils, ##@ market is full of apparatus with special appeal to the camper. When Your Car Is Stuck in the Mud—How to Get Out F, ON your motor-camping trip, you ] plan to strike away from the beaten highways into out-of-the-way places, as most campers do, the chances are that sooner or later your car is going to be stuck in a mud hole on some lonely country road. Will you be prepared for such an emergency? Will you know how to get out without ruining your tires, your gears, and your disposition? If you are impatient and foolhardy, you probably will go into “low,’’ race your motor, spin your wheels, and sink deeper and deeper in the mud until you are up to the hubs. But if you want to save trouble and expense, you will remember that it doesn’t pay to lose your head. You will sit quietly and study the best way to get out. The best way, of course, is to get some one to pull you out. But it is not always easy to find that “some one.” If you have chains, don’t try to put them on in the regular way, but wrap one entire chain twice around each rear tire cross- wise between two spokes and fasten it with the clips as best you can. Start your motor, go into reverse, and you can pull out of almost any kind of a hole. The average driver, when his car is stuck, packs around the wheel as many large stones as he can find, as shown in illustration A. He believes they will work under the wheel, as in illustration B, when the wheel is revolved, and will form a solid foundation. As a matter of fact, the stones seldom get under the wheels in sufficient number to do any good. After “‘chewing up” his tires in this experiment, he removes a few rails from a near-by fence and tries to wedge them under the wheels. The result usually is unsatisfactory, producing a _ condition such as that shown at C, or at best like that at D. Te? best way, if you have no chains, is to use a piece of rope, an old tire cover or an oilcloth side-curtain envelope, or any other bulky material you can wind around the tires to give necessary re- sistance. If you have none of these, a couple of worn-out inner tubes will serve in a pinch. The ordinary tube will go twice around a tire doubled, between two spokes, as shown in E. By cutting a hole for the valve, you can button the tube so that is will stay there. The real insurance against sticking fast in the mud, is to be prepared by always carrying with you six pieces of heavy chain, each with a hook at one end, as shown in F. Three of these chains hooked around the tire and felloe of each rear wheel will pull you out of the worst hole you can conceivably get into.

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ind the r is uch the me. > of are ving ady the act, han oS a per- rate Jing hes- cold the ires. and imi- lild- king atus ut any this rom hem ly is tion like POPULAR SCIENCE MONTHLY 73 New Ideas for the Folding Camp Five simpie operations, requiring about 30 seconds, convert this unusual camp- ers’ sedan into a cozy, insect-proof house with adequate bedroom, kitchen, locker space and toilet conveniences. Four adjustable chairs that seat the travelers in the daytime are transformed at night into two comfortable double beds This camping outfit, contained in a de- tachable box body, is designed to fit run- abouts with removable turtle backs. An upper compartment of the body carries luggage, food and cooking utensils, while the lower part carries the bedding. The rear panel drops down to serve as a dining- table. With the compartments removed and the top tilted upward, at an angle, the cabi- net serves as a sleeping tent Here is a collapsible auto-camping trailer de luxe. The upper picture shows it folded for travel. When unfolded, it provides two double bedsprings, fireless cooker, table, and icebox. The top forms a small duckboat af A new square tent of waterproof canvas can be carried on the runningboard. Instead of a center pole, the steel frame is held by four stay rods joined by a central lock adjusted by a central screw shaft, as shown in the upper picture Light folding chairs, table, and camp stove which, when collapsed, occupy small space in the car, add to the comfort of the roadside camp. The novel stove shown in the upper picture folds into the small case shown at the right

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ee 74 Repair Kinks Phan “repiac shafts are difficult to remove and replace when reassembling the car after a rear-end repair job. The jack is bolted to a wooden base to which casters are fitted so that it may be rolled around. A special yoke, made to hold the shaft, fits in place of the usual jack top, as shown in Fig. 1. By having the yoke a loose fit on the screw top, it is free to turn in all directions. To operate, -the jack is placed beneath the shaft tube and is elevated un- til the yoke takes the J OUTER Q FLAT _ RACE FREE weight of the aTrEL TO ACE unit. The set- screw is then tightened and the outfit is ready to be pulled out. This also keeps the splined end of the shaft out of the dirt. Most repair men do this work by hand, although it is a back- and arm-breaking proposition. A common screw- 4: ‘ale jack with ratchet handle can be made to assist greatly not only in this, but in other repairs. POPULAR SCIENCE MONTHLY W Breakdowns rarely hap- pen when small repairs are made promptly PIVOT STRAP Fig. 4. Drawbar connected with steering-rod simplifies task of leading an automobile ISTRIBUTER gears of certain cars cause consider- able trouble’ by jumping out of mesh when the car hits a bump or depression in the road. This 4 FLAT SIDE-” OF BOLT LIP OR BURR CENTER Fig. 2. Collar holds gears in mesh motorcycle piston ring, the dimensions of which suit the job exactly. The constant outward preg. sure of the ring seals the case most effectively, HEN fitting connecting-rod bearings, the bolts have an annoying tendency of falling down inside the crankcase. This can be prevented in the two ways shown in Fig. 6, One of these con- sists of turning a burr over the head of the bolt with a chisel or — center punch. A small burr is all that is neces- sary. A second method is to makea ring of center-punch marks around the shank. These marks should be placed halfway through the bolt hole to al- low the bolt to pivot slightly if necessary, to accommodate the cap. Bolts so remedied are Vij 7/1, A. Weel | = = ——— _—— . . agli driven into J 4 S j j AX KOS % their holes with WY N ; a light driving fit and make a neat, — service- able job. \ a —__ 77 ELLA Fig. 5. Oil seal N BOLTING on the ring gear or reaming the bushing PUNCHED . — for the pinion, the / Ving 7 | 1 f x orrerentian left half of a Ford —— oe lll oa differential case can V/, Hy | yj MH yyy be held to the bench MLB LZ, top by means of orieo/ $TuD A HOLES BOLTS” can be remedied by fastening a split col- lar to the vertical shaft just under the distributer, as shown in Fig. 2. The clamp collar is made of steel, drilled and tapped as indicated, and fitted with two small screws. In this way a permanent repair can be made without dismantling any of the motor parts. 1, ees ball-bearing roller for a creeper, shown in Fig. 3, was made out of dis- carded automobile parts and a few worn: bearings. Four of these rollers were fast- ened to a frame made of two 1 by 4 ft. boards. A padded headrest was fastened to one end to make the creeper more com- fortable. Such a rolling platform also can be utilized very well to move heavy auto parts, such as axles, around the garage. EADING a ear is a difficult thing un- less there is some one in the car to steer it. A farmer was confronted with this problem when he tried to pull the car along behind a tractor. He solved it by using a drawbar such as is shown in Fig. 4. The bar, which is 6 ft. long, is fastened to a U bolt on the front axle. A smaller - U bolt clamps the end of the bar to the Fig. 6 Two ways to hold bolts in place’ “~ WIRE SOLDERED BUSHING SHIF T- LEVER ROD WH ls HEAVY he INSULATED WIRE 1 10N SHIF T-LEVER ~—. Fig. 8. Device for shocking joy-riders steering-rod. As the front end of the bar is moved, the bar swivels on the axle fas- tening, moves the steering-rod to one side, and in this way turns the wheels in the desired direction. Cpe leakage is a frequent trouble in truck transmission systems. One truck repairman solves this problem in an ingenious manner as shown in Fig. 5. He removes the propeller shaft at the rear end and cuts a square groove in it on a lathe. Into this groove is fitted a scrapped La NN nut pencn” Fig. 7. Holding differential case on bench three studs passed through holes in the top of the bench. It would be satisfac- tory to hold the case in the jaws of a large vise, using special clamps to suit the curvature of the body of the case; but the method shown in Fig. 7 is far simpler and holds the work as rigidly as is necessary. aA/ PLS many methods have been de- vised to prevent unauthorized joy- riding, one recently installed by an elec- trician is especially novel. It was done by making a special handle for the gear-shift lever with an in- \ sulating gap between the _ ball-shaped handle and the rod. A lead from the secondary terminal of the induction coil is brought to this ball handle through the center of the shift-lever. With the engine running, any effort to shift the gears causes the full intensity of: the high- voltage current to pass through the driver as his foot is on the clutch pedal complet- ing the circuit. The current is not injurious, but is so startling that it will unnerve and weaken the most daring thief. A cut-out switch at the edge of the cowl is carefully thrown out before the owner starts to drive. due sho yea car: ser’ yea att can cor ene exp the are con Las of « and bur vas cot: Car 101 sary ing pro For mo’ or 1 roa

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cS yhich pres- vely, , the alling ented ways . con- ng a head ith a enter | burr 1eces- 2cond ake a yunch | the narks laced yay the to al- olt to ntly if . odate Bolts ed are into s with riving lake a >rvice- 1G on ear or ushing n, the . Ford se can bench ins of passed _in the ich. It itisfac- he case special e body in Fig. ‘ork as een de- ed joy- in elec- special 1 an in- shaped om the n coil is igh the engine > gears 2 ~high- e driver om plet- ut is so weaken vitch at thrown e: POPULAR SCIENCE MONTHLY 75 Arthur Wakeling, Edi re or Equipment for Auto-Camping in Comfort By Harold N. Whitmore, M.E. F YOU are going auto-camping this [ ome and wish to have genuine comfort and convenience without un- due cost, I can recommend the equipment shown in the accompanying illustrations. Designed and built at home after a year’s study of various types of camping cars, the outfit gave most satisfactory service in a summer spent outdoors last year and will be used again this year. It attracted much attention at every tourist camp I visited, principally because it in- corporates many of the conveni- ences of more elaborate and more expensive outfits without some of their objectionable features. Among the outstanding features are compactness, light weight, and comfortable sleeping quarters. Last, but not least, with this type of equipment, the runningboards and the inside of the car are not burdened and crowded with can- vas, poles, boxes, stoves, chairs, cots, and other paraphernalia. Camp may be set up in eight or 10 minutes. The cost of the materials neces- sary for building the outfit, includ- the ing cooking equipment, was ap- proximately $100, with careful buying. The outfit is attached to a standard Ford runabout with the turtle back re- moved. However, it may be attached or modified to suit many other makes of roadsters and coupés. The small illustration at the right of Fig. 1 shows the rig as it appears on the road. Everything is inclosed within the box on the back, which in turn is covered with waterproof canvas and held in place with a well known type of patented, lift socket fasteners. The spare tire is carried suspended on straps under the rear of the truck box. The entire weight is about equal to an empty Ford sedan. In Fig. 2 the canvas cover is shown Fig. 2. Side windows, tent poles, and bed- springs with storage drawer underneath a ew ~ tine hint Fig. 1. and the entire equipment packed in arms support the awning, which covers the kitchen compartment. The front end of the ridge pole is attached to the top of the car between two angle irons, through which a pin passes. The upright pole is made of wood with 14-in. iron pins in each end. The upper pin passes through a hole in the ridge pole, while the lower pin passes through a hole in the iron frame of the bedsprings. The bedsprings are visible in this view. The drawer containing sup- plies, stove, and other equipment is in place under the bed. The central illustration in Fig. 1 mae é f is a side view with canvas in place and the drawer pulled out. The canvas is attached with the cur- tain fasteners mentioned before. The arms extending from the ridge pole support the front of the awning, while a collapsible 14-in. pipe is inserted in a canvas tunnel at the back. Two wooden poles in the body with metal How camp is made (above) body for touring (at right) removed and the top opened out to form the sides and screened win- dows of the sleeping compartment. The tail gate is down and the ridge pole in place. The two arms extending from the ridge pole are on hinges and fold back against the ridge pole for packing. These SUPPORTS — on } } | RIOGE POLE HELD = ON AUTO TOP CANVAS SLIDING TOP == . a hh. EDRs \ oe eae ‘FT SPRING \ DRAWER 4'-G* LONG 9 * 5:0! -{ —_ \ RIDGE POLE> SG: or SCREEN FRAMES CANVAS TO ROLL DOWN SLIDING TOP__I— Pig. 3. Main di- mensions of outfit for use with light runabout (WATER FAUCET TAIL GATE-D _ | } pins in each end hold the awning in place. In order to avoid too great an over- hang, the box and consequently the bed- springs are only 5 ft. long. However, the mattress is 6 ft. long, the extra foot being supported at night by the sliding top provided on the drawer. The canvas end covering this extension, as well as the entrance to the bed, is shown in this view (Fig. 1). The drawer is supported on ad- justable and detachable legs. In this illustration also appear the tent ropes, which provide means of stretching the canvas roof of the sleeping compartment. Figure 4 shows a three-quarter rear view with the side drops attached to the awning. These drops are put on in bad weather and at night. There is one (Continued on page 118) Fig. 4. Awnings and side drops in place for the night. Note screened windows

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76 HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY Built in Place to Save Labor Garage Doors By Edwin M. Love MATEUR carpenters usually make A hard work out of the building of garage doors; and not a few good carpenters pursue methods that are slower and more difficult than that herein de- scribed. In all types of doors consisting of stiles and rails sheathed up the back, run the top and bottom rails the full width of the doors, and cut the stiles between (Fig. 3). This system is contrary to ordinary door construction, but admirably adapted to the rapid building of strong garage doors. The opening rarely should be less than 714 ft. in height. Case the head jamb, cut the 1 by 6 in. top and bottom rails 6 or 8 in. longer than the width of the opening, and nail them in position, allowing !¢ in. clearance at the top and !4% in. at the bottom. If a pair of doors is to be built, as the illustration shows, tack the center stiles in oat position. For 7 sheathing ma- terial, 6-in. V- grooved ___red- wood ceiling 34 in. thick usu- ally is used in my own local- ity in Califor- nia. It should be cut 1% in. less than the length of the completed door and applied with a 14-in. margin at top and bottom. Ceil from the center, as in Fig. 1, by toe- nailing top and bottom with fourpenny box nails. When a few boards are in place, cut in the center rails between the stiles and nail solidly to the sheathing. Then complete nailing on the ceiling. For a single sliding door, no braces are required. For double doors, either hinged or combination hinged and sliding, braces should be_ provided, toward the front edges. All the ceiling being on, nail each edge running upward See Ga Fig. 1. Nailing on the panel material (at left). Fig. 2. Cutting the rails (above). Fig. 3. The finished doors (upper right hand) from the front with sixpenny box nails staggered to catch both edges of the rails and stiles. Then clinch the nails at the back, either by driving the points over and into the ceiling with a nail set, or by having a helper hold an ax against the nail heads while the points are driven over. A door built in this way is fitted and in position for hanging. Tack blocks to the upper ends of the stiles and the casing above, as in Fig. 2, and saw through the rails. Case the side jambs and apply hinges, or hangers, and re- . move the LEN blocks. Noth- : ing remains but to dress the sawed ends of the rails and to put on the re mainder of the hardware. Doors like these are capable of standing a surprising amount of wear and tear, and are amply strong for mild climates. If subjected to storm and freezing, the fol- lowing modification is recommended: After building the door to the point of nailing from the front through the stiles and rails, reenforce with rails and stiles behind the ceiling, extending the center rail the full width of the single door and the stiles to the top and bottom, as shown in Fig. 4, after- ward nailing solidly from the face of the door as described above, using tenpenny box nails clinched at the back. It is an excel- lent practice to coat all joints and lapping sur- faceswithheavy paint as the parts are put in place, as this safeguards against damp- ness. BACK STILE GOES TO TOP BACK CENTER BRAIL FRONT CENTER RAIL FRONT STILE fMTBUTTS AGAINST RAIL BOTTOM RAIL Fig. 4. Detail of doubled rails and_ stiles Novel Bunny Rocker Will Amuse Any Small Child O amuse Junior, the little rocker illus- trated hasmany merits. The un- usual design of the rocker piece prevents him from rocking too far forward or back. The back rest supports his back and keeps him from sliding off. The rabbit’s ears afford a convenient hand-hold, and if the baby does manage to fall off, the seat is so close to the floor that no harm will result. The rocker is not difficult to make and decorate and will give the youngster many hours of amusement. Use a soft wood, as it is easy to work and will look well when enameled. For the seat you will need a piece of %-in. stock, 1 ft. 6 in. long and 10 in. wide. Lay out a center line lengthwise of the board. Set compass or dividers for 5 in. and lay out a half circle at one end. Lay out the other curves, and shape by using the draw-knife and the plane to fin- ish the curves wherever possible. ’ By use of the squares, each of which ELAR ON a / Se ee a at x) ‘Vv | | Se ee ae eS ee ee XG S : | eco ee ee Le ————— —— oe — S$ LYN | | i Working drawings of [ T \ ' rt the rocker based on ——t — l-in. squares, and | |_| NY, views of finished toy | Lind | Lie | | 7] _ | | —_ { —| | | | s Maa oR Lar tT Ti TiN 1 / Cook oe J — Lda tJ represents one square inch, lay out the head of the rabbit, with the grain running vertically. A turning saw is a good tool for cutting out the head. The squares also will facilitate laying out the rocker pieces, two of which are needed. Next, cut out the back piece. Plane the lower edge so that it will tip back slightly when fastened to the seat. In assem- bling, use long screws or finishing nails. If screws are ‘used, set the heads into the wood and fill the holes with wooden plugs. If nails are used, putty will do to fill up the holes when the heads have been set in. Sand the job thoroughly, finishing up with 00 sandpaper. Paint the rockers and the head white, and the seat and back piece a bright red. Give two or more coats, as needed. When the last coat is thoroughly dry, take a fine brush and paint the eyes, whiskers, and mouth and outline of the ear with black enamel. Use pink, if at hand, for tinting the nose and indicating the markings on the inside of the ears—KENNETH R. La Voy. | glas side rem tong Neo ____sAYT

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in saw the the and 3, OF l re- »th- but the ; of 1 to re- ling and If fol- led: t of tiles tiles nter and own ILE TOP NTER NTER TILE \INST led ro (of are Next, the ece. lower nat it back when 0 the ssem- . long ys are nd fill ils are holes ng up rs and back more oat is h and h and Use se and side of HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY 77 Toy Roadster Has Electric Drive Flooring for Furniture HE home workshop enthusiast who has but few tools sometimes finds it hard to make panel and glass doors for furniture on account of the lack of groov- ing or combination planes. I have found that the use of grooved flooring for the frames of the panel doors and glass doors solves this problem for me. The flooring comes in so many grades and widths that almost any need may be met by using it. For panel doors the ‘‘tongue’”’ of the flooring is removed and the panel mounted in the grooves of the inside of the frame. For glass doors, the tongue and one of the sides of the groove are removed, and the AETONGUE Ca REMOVED i; GROOVE A] NT \\\h | i REMOVED le We PN LK GROOVE - a REMOVED FLOORING STRIP IP ONE SIDE OF cetiaie GROOVE REMOVED TONGUE Neat door frames made with flooring glass is mounted against the remaining side of the groove. Another method is to remove the groove side of the flooring and mount the glass against one side of the tongue, as illustrated above. Money-Saving HREE unusually popular spring projects for the home worker are the pergola garage, the baby’s crib and play pen, and the canoe sailing outfit illustrated. Selected from POPULAR SCIENCE MONTHLY’S long list of blueprints in re- sponse to the requests of readers, these designs are especially appropriate for con- struction at this time of the year. They can be built at a considerable saving over their commercial equivalents. For the man who has bought or is going to buy his first car, the pergola garage has many advantages. Costing only from Blueprint No. 23 CONSTRUCTION OF ROOF col al is more than a miniature automobile that will run like a real car. To build such a toy is within the ability of any skilful mechanic, although it would be difficult to equal the remarkable com- pleteness and fin- Pirrvre' ti no toy delights children The motor is an old automobile genera- tor rewound for this purpose. The cur- rent consumption for motive power only is from 9 to 12 amperes; the lights, which include headlights, dash and _ tail-light, require 5 amperes, and the horn, 3 amperes. ished workmanship | } ~~ en, For the sake of of the unique little ee ints aie safety and in mercy roadster illustrated. t a oe o ve@l.,,| to daddy, who walks This car was de- =“! while his little signed and built at the Motor Trans- portation Repair , Shop of the Coast |; “Vd Artillery School, | 4 Fort Monroe, Va., by Technical Ser- geant Theodore P. Gunther for his five- year-old daughter, Pauline. The work required about 700 hours of Sergeant Gunther’s spare time, spread over five months, and he still has to add a windshield and top. daughter rides, the speed is limited to a maximum of 6 miles an_ hour. The controls are the same as in most pas- senger cars; that is, clutch and_ brake pedals, gearshift The miniature lever, emergency machine in brake lever, spark —— and throttle levers. with a stan- dard army pas- There are three senger car speeds forward and one reverse. The motor and running gear are protected by a safety device that makes it impossible to injure any The roadster is operated by a stor- age battery and electric motor, belt driven to the differen- tial. The battery, which consists of seven cells of 120-ampere-hour capacity, is divided into three sections, two of two cells each being under the hood in front and the remaining section, of three cells, in the rear compartment. They are con- nected in series to give 14 volts altogether. The toy auto, with its five- year-old driver at the wheel part of the mechanism by faulty manipulation of the controls. Miss Pauline has driven her car from 250 to 275 miles without a break- down, and she handles it like a seasoned driver. She knows her simple traffic rules and the customary hand signals to those in the rear and she can talk automobile from the front bumper to the spare wheel. The novel little car has became a familiar sight in and around Fortress Monroe. Plans for Your Home Workshop $150 to $200 for all ma- terials, it is different from common stock de- signs and fits well in a garden setting. Full working details and bill of materials are con- tained in Blueprint No. DOWELS Sits 4 gS | } Ae, — ’ ‘ a - A» 23 € 23, listed Framework and front of the pergola garage with details of sill and plate (at left) and baby’s crib and play pen from Blueprint No. 26 (at right) on page 107. The crib and play pen, which is detailed com- pletely in Blueprint No. 26, Durable sailing outfit for canoe Blueprint No. 25 has an adjustable mattress frame which is attached to the lower frame with 14-in. rule joint stay or support hinges, so that it can be raised readily. The sportsman and canoeist will find the sailing outfit for a paddling canoe (Blue- print No. 25) an improvement over ordi- nary designs. Each blueprint can be obtained for 25 cents from POPULAR SCIENCE MONTHLY.

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78 HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY Simple Buffet to Complete Dining-Room Set has been ommitted fro the furni- ture of many dining-rooms, espe- cially when there is a built-in china closet in the room. This gap in the furnishings may be closed readily and inexpensively by building a buffet in the home workshop. The Adam style buffet illustrated, in which straight lines predom- inate, requires a minimum P's: one reason or another a buffet By E. E. Scott 40 lineal ft. of 14-in. birch or maple strips 2 in. wide for the inside framework, which also serves as runways for the drawers. The first step is to make up the legs in pairs, mortised to receive the framing strips and the end panels. If possible,

of time and skill. Mahogany or baywood, which is really a grade of mahogany, is the most suitable wood for this particular design, although oak or birch will answer nearly as well, depending upon the furniture that is to be matched. The first consideration is to select stock that is free from checks; if wood other than mahogany is used, all warped and knotty pieces should be rejected—mahog- any rarely warps or checks and that which reaches this country usually contains no knots. Twenty board feet of

Excellent proportions and sim- plicity of design dis- tinguish this unusu- ally attrac- tive home- made buffet = the parts wherever the thickness of the stock permits. Before the top is put on, the whole interior framework should be assembled and the drawers made and fitted so they will slide easily. Put small stops at the back to prevent the drawers from being. pushed in too far. If polished steel draw; slides, like thumbtacks, are used at the front of the drawer runs, they will reduce the friction considerably. The drawers may be subdivided as de- sired. The top middle drawer in this case has divisions for forks, knives, and spoons and extra pieces, and a narrow, false and secret section in the rear for solid silver. If it is desired to have the drawers espe- cially strong and no machine work is to be done on the joints, they

should be made of ma- ple or birch

and held to- gether with

7%-in. stock are required for the top, back board, doors, and drawers; 6 ft. of 34-in. stock for the end panels, and 13 running ft. of 2 by 2 in. stock for the legs. The “out of sight’? parts of the drawers, back, and bottom may be made of 34-in. whitewood, of which 35 board ft. are required. There also will be required have the mortise for the end panels run out on asawtable at the mill, as it is important the fit should be accurate. bling the frame, it is convenient to use flaked cabinet glue melted in hot water

When assem- and applied while hot. Dowel together

How to Adjust Your Auto Valve Tappets \ , JILL you remove the carbon from the engine for me this morn- ing?” asked an owner friend the other day. ‘You know,” he continued, “that is about all I ever have done to the car. I used to have the valves ground every two or three thousand miles before I learned how to set up the tappets. “When I first got the car, I had one noisy tappet. I adjusted that so it was quiet, and then found there was another one louder than the rest. I kept on setting them closer and closer until I was losing power, and had to be grinding the valves every little while. Finally I set them all with considerable clearance, and tried to get them all just the same. The engine was not quite so quiet, but there was no annoying noise. I have driven the car 32,000 miles, and have not ground the valves since.” This owner has learned the secret of economical valve care. Valves set too close will become sooted and burned. Many very quiet engines lack power be- cause the valves are set so close that when the engine gets hot, the valves are on the verge of holding open. This results in burned and pitted valves, and, if con- tinued for any length of time, will result in worn and noisy valve mechanism, since the force of the explosion must be borne by the valve stem and cam. The poppet type of valve requires on an average of .006 in. clearance between the bottom of the valve stem and the lifter, if _ in an L or TW head, and the push rods on the I or overhead type require as much. To prevent an irregular noise, set all tappets just the same. This results in a regular sort of hum from the engine, but the noise will not be objectionable. An en- gine that will give only a thousand miles before making trouble with closely ad- justed tappets, can then be driven almost indefinitely without valve trouble if these hints are observed.—Ray F. KUNs. VALVE MUST CLOSE f} \ OR BURNING GASES aN) == \

Diagram showing eed correct and in- E correct Ned adjust- ments of valve tappets | ow cal , - TOO MUCH CLEARANCE, = VALVE OPENS TOO = ew | LATE,CLOSES TOO CLEARAN E . 4 — ANC | aah pa JUST RIGHT oj 4 .0OG" NO CLEARANCE; VALVE CANNOT ADJUSTING mM CLOSE NUT les tt \ LOCKNUT 4 L TAPPET ——— Ce) 4) —— ais <e q When the clearance is correctly set, the valves : rarely have oes — to be ground

| long, thin | screws. | The top = can be put ¢| together either with dowels or with splined joints, the latter being a mill operation. For the most satisfactory results it may be as well to have the top splined and glued at the mill, where it also can be run through the planer and all inequalities removed. If; this is done with mahogany, the joints are nearly invisible. The top is held on by a 34 by 1 in. strip on all sides except the front, where the top framing strip serves this purpose. It will be noted that the top overhangs 1 in. on all sides except the back, where it is flush. The back board is not attached until the finishing is complete, the piece being made up and finished separately and held in position with screws. This is so that it can be taken off if necessary for moving.

HE wooden door and drawer knobs can be turned or purchased unfin- ished. Hinges, locks, catches, and casters complete the fittings. To finish the piece, first apply a coat of dark red or, preferably, brown mahogany stain. Allow the wood to dry for 24 hours and apply another coat, wiping off all sur- plus stain. After another 24 hours, apply a coat of white shellac well thinned down with denatured alcohol and allow it to dry thoroughly, after which it should be finely ‘sanded. Follow with a coat of any stan- dard furniture varnish and sand well. A second and third coat should be ap- plied, each of which should be sanded smooth and rubbed with fine powdered pumice-stone. The method I use is to sprinkle the surface liberally with pumice and enough oil to form a paste when 1ubbed circularly with a wad of cloth.

“TAHE Home Workshop Department’s series of articles on built-in furni- ture of the type now so popular, will be resumed next month with an article by Edwin M. Love on corner china closets.

rE JO] per bea slig hot Re

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POPULAR SCIENCE MONTHLY 79 FREE—Book on Wood Finishi a aca ot —DOOK Of1 VWWOO UMS TIE the bole = If you have a hobby for making porch furniture, thet radio boxes, cabinets, etc., you will find this Book ina invaluable. Naturally, you want to give your irae handiwork a beautiful finish, Our Book gives duce complete instructions for finishing all wood— del hard or soft, old or new. It is the work of ex- oul perts—beautifully illustrated in color. Gives cov- — r ering capacities—includes color charts, etc. aspee N ¢&SO | told S CJ OHNSD Authorities. n the The Woods INE, WIS.USA- they be f ma- birch id to- ith “1 JOHNSON’S WOOD DYE top > put { her — JOHNSON’S WOOD DYE JOHNSON’S WOOD DYE slined is for the artistic coloring comes in all sizes from the of all wood. With it in- half pints to gallons. It : = expensive soft woods is made in seventeen at the such as pine, cypress, fir, popular shades all of h the etc., may be finished so which may be easily . they are as beautiful and lightened or darkened. artistic as hardwood. Full directions on every . strip Johnson’s Wood Dye is label. gee very easy to apply—it in. on goes on easily and quickly ye without a lap or a streak. 1 e bps Johnson’s Wood Dye has many uses, for both the artisan and hat it amateur. Architects and contractors specify it for coloring ving. A Paes e Hil ie. woodwork and flooring in new buildings. Painters and |}—== = decorators use it with equal satisfaction on new and old dniuson’s Woop Dit asters wood-work of all kinds. Housewives delight in it for doing oat of over old furniture and for coloring reed and wicker baskets, etc. a Manual training teachers and pupils use it for finishing Il sur- their models. Upholsterers, furniture repairers and = cabinet makers find it ‘‘just the thing’? for their work— to dry old and new. finely stan- = (YO! PPP OE ee eee ee ee 1. JOHNSON’S WOOD DYE has wonderful ~ i ie penetrating qualities—it brings out the pao? Madibind #: ony eves Sapiaing tee ge cewwe ae tate : vdered | beauty of the grain without raising it in the If no store in your locality has a Johnson Service De- & > is to | slightest. It dries in four hours and will i pumice | not rub off or smudge. DEALER’S NAME - - when Your Name ‘ Address ment’s Ss. C. JOHNSON & SON City and State ' sige “The Wood Finishing Authorities’’ Mail to : article . S. C. JOHNSON & SON, Dept. P.S. 6, RACINE, WIS. 5 china Racine, Wisconsin, U. Ss. A. ee oe ee ee ee es es oe oe me

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80 POPULAR SCIENCE MONTHLY

Better Shop Methods, How Expert Mechanics Save Time and Labor

By H. L. Wheeler Machine-Shop Foreman F ALL the machines in the machine-shop, the engine lathe stands preeminent. Itis the most useful and universal machine, and the ancestor of all the machinery in the world today. In the hands of an expert its range and possibilities are almost infinite. To get the most out of a lathe, it should be located in the shop to the best advan- tage, preferably near a window facing east or west, or at the point where the best light comes into the shop. The strongest rays should come over the right shoulder of the operator. Next in consideration should be the foundation. The lathe should rest on a firm floor and be leveled up and in good alinement with the countershaft, and be fastened firmly. The countershaft also must be level; and the line shaft, countershaft, and lathe spindle, parallel. Most of the trouble experienced with counter- shafts is due to their being out of line with the lathe, not being properly leveled up, or lacking oil. If the lathe is set up above the ground floor, the floor itself should be firm. If the floor shows any signs of weakness, it should be braced from underneath where the lathe will rest. Long, heavy lathes must be supported on a strong foundation, and it is always best to set them up on the WRONG WAY FIG. COOL It is surprising that any machinist should neglect oiling his machines. All oil holes should be oiled regularly with a good grade of machine oil. Special attention should be given the main spindle bear- ings. Where no regular oiler is employed, the countershaft, as a rule, gets very little ‘ S one ik =: a ‘ 4 - re wr

Ge Pa

ground floor and have the lathe bed rest directly on a good con- crete or brick foundation. The long bed must be supported at several points to prevent sagging. Another point is the provision

RIGHT WAY FIG2 TESTINGCENTER FIG3

TAPER a?

with a can, as it only runs off and js wasted. It is a common sight to see the ways of a lathe littered up with files, hammers, and wrenches. Sometimes heavy, rough castings are piled on them. This is very bad practice, to say the least, and does not contribute to keeping the lathe in the best of condition. A lathe should be pro- vided with a board that will slide along on the ways in the rear of the tailstock. Such a board is shown in Fig. 6. Simply constructed and costing very little, it will hold all the tools used and any other small articles that may be required for a job. Such small attentions tend to prolong the life of the lathe and keep it in good condi- tion as well as to save much time other- wise wasted in repairs. . For turning accurate work on centers, it is necessary that the centers run true and in line with each other. The trueness of both centers is tested in the spindle while running at a high speed. Any variation from the true center is usually apparent to the eye. When the centers need to be trued, the best | method is to use a_ toolpost | grinder. If one is not available, the hard center will have to be annealed and trued up with a tool. AREA OF HEAT ss PENETRATION 4 LOW VERY HOT //)' A HEAT ce TOOL BOARD FORGED TOOL DRIVE COLLAR a (f FEED COLLARS re TO FIT INSIDE OF WAYS =O C0? ‘Ta tail center must always be hardened, as all of the wear comes on this center. The centers should always be made of carbon tool steel of about 1.05 to 1.15 carbon. The standard angle is 60 degrees and this angle should never be guessed at

of ample space all around the ma- BOLTS when __ truing chine so that up the cen- the operator 4; ALLOW 18 ON EACH SIDE ters. The will be free to - i} proper thing pass around (Z| : CY MASTER COUNTER- is to test it and wor k C: ae Sega Ho NUT teed SAM —" wh» center from all sides. \ OFF CAM = F— ROLLER, HARDENED gage (Fig. 3). Whenever a ~ ‘ == i O fA STEEL Always chuck or face j oe ) % ae |_ PLATE SWIVELS ON make sure plate is —— [et ; | ch < TO EQ aTUDIN CENTER OF that the holes mounted, care [ai ine eCoee | __ DETAIL OF TOOLY =| B eaititataied in spindle and should be 120 7 60° 1 120° — 60 RIGHT AND LEFT teilstock are 6 age pal DEVELOPMENT OF CAM —s FIG CENTER OF COMPOUNDL___IFIG.9 that chips and dirt have not lodged in the thread. The threaded hole should be wiped out with a clean piece of waste and oiled before it is placed on the lathe spindle. A chuck or face plate should not be run up to the shoulder suddenly, as that strains the threads and makes it difficult to remove. One of the common causes of trouble ‘ with a lathe is lack of proper lubrication. Sliding tool table, boring rig, method of turning steep tapers, cam attachment, and other suggestions attention and not until one of the boxes heats up and sticks does it get any oil. This may cause a four- or five-hour repair job, when it would have been only a five- minute job to oil it. The ways of the bed and the V’s of the saddle need oil as well as the other parts, and this is another point all too frequently neglected. The oil should be rubbed on with the hands and not just squirted on

free from dirt. When center- ing work, it is best to use a standard combination drill and countersink. This assures the centers: being perfect and gives the proper bearing in the work, as illustrated in Figs. 1 and 2. The tail center requires oil and should never be allowed to run dry. Stop imme- diately when the center begins to squeal. If heavy cuts are taken on steel shafts, the heat generated by the cut expands the (Continued on page 94)

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and is vays of mmers, , Tough is very 1d does > in the be pro- e along ilstock, Simply , it will >r small a job. ong the 1 condi- » other- centers, un. true r. The ; tested ‘unning rriation usually 1en the he best oolpost ailable, » to be | a tool. always of the . The - made ut 1.05 andard is 60 ; and ingle never ssed at truing > cen- The thing test it center ‘ig. 3). yvays sure e holes lle and. k are m dirt. center- k, it is yn. drill centers | yearing and 2. should imme- squeal. ts, the ds the

POPULAR SCIENCE MONTHLY

“What’s Eddie ee looking so black about?” H, he’s sore because I won’t lend him my Starrett Com- bination Square—the one tool I can’t get along without.”’ “Well, he’ll get over it. One of these days he’ll buy one and see for himself why it’s such a hard tool to borrow.” STARRETT UST as it stands the Starrett Combination Square Combination Square gives you seven tool uses combined in a single handy, No. 11 accurate tool. Rule, Try Square, Level and Plumb, Depth Gage, Height Gage, Scriber and Miter. But add a Starrett Protractor Head, Center Head and other Attachments and at a small cost you have doubled the usefulness of this splendid tool. For more rapid work and more accurate work from fewer tools get a Starrett Combination Set at any good hardware store. The new Starrett Catalog No. 23 ““W”’ shows the various Ps. Attachments that can be added and illustrates the many " different uses. Write for it. THE L.S. STARRETT CO. The World’s Greatest Toolmakers Manufacturers of Hacksaws Unexcelled = << ATHOL, MASS.

nod, Tools

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82 BETTER SHOP METHODS DEPARTMENT OF POPULAR SCIENCE MONTHLY Do your tools reeommend you for the job? OQ matter how skillful you are, there’s a certain added respect and admiration that a tool kit of good tools brings you from the boss you work for. He*knows good tools—he can tell a carefully selected tool kit—and he knows the man who owns such a tool kit is the careful, thoughtful man he wants for the job. The right kind of tools in your tool kit is a good advertisement for you no matter where you go. Brown & Sharpe tools are tools you can rely on to add to your good reputation. They are made by the first and largest maker of precision tools in America. They are known world-wide for their steadfast reliability and high quality. Send for our Small Tool Catalog. BROWN & SHARPE MFG. CO. Providence, R.I., U.S. A. BROWN & SHARPE TOOLS “The Standard of the Mechanical World” Machining Large Bushings in Lathe and Planer ie machining of large bushings is difficult because the thin walls are easily crushed when placed in a chuck. While the rear end can readily be held on a spider at the tail center, the chuck will spring the bushing if it is not re- inforced. A light spider for the head end can be made of a pipe cross fitting and four nipples. In splitting large bushings accurately, care must be taken to have the cutting PIPE SPIDER aaa a LARGE BUSHING SPLITTING TOOLS PIPE patel NIPPLES . ag 7 am FRONT TOOL cS will REAR TOOL qt — PLANER BED Spider for reinforcing pipe held in lathe chuck and method of splitting large bushings tool move in a straight line. This cannot easily be done in the milling machine, for one side of the miller is apt to drag, even with a perfect tool. On a planer, the bushing can be split correctly if two tools are used, one in rear of.the other. The front tool is the narrower. The bushing is held in place by clamps fast- ened to four angle plates. This use of two tools prevents chattering and keeps the cut straight, while the clamps pre- vent the side walls from collapsing. Filing Holes in Thin Metal HEN fil- SLOoTIN (=7ZN THIN ing a hole iY] > ~y in thin sheet metal, I make a slot in a piece of wood with a screwdriver or a blunt tool to take the metal so that the inside of the hole will be flush or a trifle above the surface. With one hand holding the top of the metal, I can file the hole quicker and better than if the work were clamped in a vise. Facing and Chamfering Nuts TT facing arid chamfering of nuts can be accomplished by the single flat face tool illustrated. One corner is rounded for use while facing and the flat end does the chamfering. Not only does this tool avoid wasting time in changing tools, but it also gives all nuts the same angle,thereby im- proving the ap- pearance of the HOLDER--% = ‘s-TOOL = work.—E. C. F. CHAMFER /

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POPULAR SCIENCE MONTHLY 83 More Wen you take radioaway with you—take Eveready Radio “A” and “B” Batteries, the batteries whose great power lasts longer. Remember, summer's the time when radio signals are weaker. Batteries do get used up in time. The ones you've been using, though partly exhausted, may be satis- factory for the strong winter signals, but are prob- ably inadequate for the weaker summer signals. For instance, use the familiar standard 22'4-volt Eveready “B” Battery No. 766. It has variable taps for ‘“‘soft’’ detector tubes. Put two, three or four in series to provide sufficient power for amplifiers. To light the filaments of your dry cell vacuum tubes for the longest time, use Eveready Dry Cell Radio “A” Battery No. 7111. The Eveready “A” will astonish you by its long-sustained vigor. It is advisable to use two Eveready “A's” connected in Power for Summer Radio Informative and money-saving booklets on radio batteries you have any questions regarding radio batteries, write to G. No. 7111 Eveready “A” Dry Cell The best battery for use with dry cell tubes Nonny EVEREADY R AD10 BATTERY EVEREADY ~ RADIO "B BATTERY WS CELLS 165-168-194: Zier 22m VOLTS tter: outoaas Reh eS Pascoe No. 766 “B” Battery, 22 34 volts multiple for each WD-11 or WD-12 tube—this gives the economical “eighth” ampere drain per cell which insures maximum economy and longer life. For sets employing one to three UV-199 tubes use three Eveready Dry Cell Radio “A” Batteries No. 7111 connected in series. The greatest electro-chemical laboratory known created these famous dry-cell batteries on which radio largely depends. The experience of thirty years in battery making stands back of them. Eveready Radio “A” and “B” Batteries—lively, peppy, long-lived producers of power. For your light-weight sets to take camping or on hikes, Eveready has suitable small batteries. Manufactured and guaranteed by Nationa Carson Company, Inc., New York—San Francisco Headquarters for Radio Battery Information Canadian National Carbon Co., Limited, Toronto, Ontario sent free on request. If >. Furness, Manager, Radio Division, National Carbon Company, Inc., 116 Thompson Avenue, Long Island City, N.Y. Eveready — 6-volt (Sf) Storage a “At No. 771 Battery “C” Battery No. 763 “B” Battery 0. 764 N “B” Battery cS : EVEREADY Radio Batteries -they last longer

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BETTER SHOP METHODS DEPARTMENT OF POPULAR SCIENCE MONTHLY Hand and Breast Drill 1616 Price $4.50 (7 Light in weight low in price HERE IS A HAND DRILL that has the advantage of being light weight and easily handled—and it is also low priced. Aluminum frame. Steel pinion gear. The guard of hardened steel holds the gears from slip- ping under extreme pressure. The steel spindle runs on ball bearings, and keeps end-thrust friction out of the tool and puts it into the job. All-steel chuck with three hardened jaws that grip all round-shank drills up to 3¢-inch diameter. Write for the Goodell-Pratt Catalog No. 15, which shows the entire line of 1500 Good Tools. It’s free. GOODELL-PRATT COMPANY GREENFIELD MASS., U.S. A. Makers of Mr. Punch = GOODELL PRATT 1500 GOOD TOOLS How to Remove Broken Taps and Drills Successfully By John Aures ERHAPS no machine-shop foreman is better known to mechanics the country over than Old Bill. He isa kindly, keen-witted machinist, ever lending a helpful hand to other work- men. He was a friend of the late Joe V. Romig, who drafted him as a sort of fiction character for a long series of articles planned for the Better Shop Methods Department of POPULAR SCIENCE MONTHLY. This series will be completed by other well-known mechanics, as in the article below. " HEN are you going to finish that tapping?” inquired Old Bill, the foreman, as he came up to a young me- | chanie who was pounding away on a cylinder block. The perspiring youth laid down his punch and hammer, as he turned to the foreman and sadly admitted that he Ay) Old Bill "talks on broken taps couldn’t get out a tap he had broken off some time before. With his usual kindli- ness, Old Bill took the time to tell him the best methods of removing broken taps and drills. The subject is one of such general interest to shopmen, that the substance of Old Bill’s lecture is weil worth repeating. Taps and drills break off in work, at times, regardless of what precautions may be taken, as the large breakage in all plants will show. The loss of the tap or drill is nearly always secondary to the re- moval of it, as in most cases this means an F1G.2 Four methods useful in removing taps expenditure of much time and patience, particularly where the removal of them is not understood. Attempts at backing out broken tools of this kind with a hammer and a punch | should never be made except as a last (Continued on page 86) } | |

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POPULAR SCIENCE MONTHLY 85 Esa The size of the job There’s a NICHOLSON File doe snt vnatter! of the size, shape and cut for every ; , purpose. Where coarse casting surfaces need smoothing, . as well as for all kinds of fine filing, you can To be sure you’re right, safely intrust it to a NICHOLSON File. select the type of file : j you need--and buy Lhere’s this much “family resemblance” only files that have this among all NICHOLSON Files. trademark on their tangs --- They are of keen temper--- Of remarkable edgeholding stamina--- Of absolute uniformity---‘12 Perfect Files US, in Every Dozen.” U S A First-class Hardware Dealers carry complete stocks of NICHOLSON Files. (TRADE MARK} NICHOLSON FILE COMPANY Providence, R.1., U.S.A. = = ea SOS N EN ENE S IIE S = % NICHC OLSON FILES

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86 BETTER SHOP METHODS DEPARTMENT OF POPULAR SCIENCE MONTHLY

\ at o- ot OeZ ®, a , . @ easy ~~ ee A \: PAYS She % 2 @ ee * 190999! ) TY oae A! sep eee *“eveces ee tecec re OP OG O< $99 0@< ‘Soeqe- / ‘S2te0c ) WV peteees * ¥O¢@e: CPOEO ME PSCel wg ‘eee ee. POR BER ey — ”, - Let's go back along the Road to Yesterday OMEWHERE back among the days of the old swimmin’ hole and cat- fishin’ along the river bank, there’s one day that was long remembered — the day that first toy tool chest came. Mother probably worried about you sawing up the legs of the old square piano. Dad prob- ably looked on and smoked himself into pipe dreams of your future. And you... why you knew you'd grown up. Why not gratify the liking that you’ve still got for good tools by including in your tool equipment a Simonds Hand Saw,Hack Saw and File? Simonds cutting tools are backed by 92 years of manufacturing experience. They represent the best of steel, fashioned into the best of tools by the best of crafts- manship. But, when you buy your good tools, be sure to say SILMONDS. SIMONDS SAW AND STEEL CO. “The Saw Makers” Established 1832 Fitchburg, Mass. Branch Offices in Principal Cities

How to Remove Broken Taps (Continued from page 84) resource before consigning the part to an annealing furnace. It is better to try to secure a firm grip on the tap or drill with a tool of some kind. I use one or two tap wrenches of the type shown in Fig. 1. The jaws of the wrench are altered so as to enter the flutes of the broken tap and then rehardened. By tightening the wrench onto the broken tap, it often can be removed easily. A single tap wrench like this can be used on several taps of different sizes. For removing broken drills, a wrench with two opposite jaws removed will have to be used. Of course, this tool can be used only where the tap or drill is broken off close to the surface of the work, as is usually the case. If the tap is broken off deep in the hole, take a piece of cold rolled steel of suitable size and turn it down to the drill size of the tapped hole. Drill a hole into one end of this the size of the diameter across the flutes of the tap. Notch this end so as to fit into the flutes of the broken part of the tap and case-harden (Fig. 2). Many broken drills and taps can be removed with a tool of this kind. THE tap is broken off so that one side is much higher than the other, grind off squarely the broken part of the tap that is left and run it into the hole as far as the broken-off piece. Turn the tap until the flutes are lined up and insert into each one of them a piece of drill rod of a size that will just fit. Then runa nut the size of the tap over the ends of the drill rods close to the work, as in Fig. 3. If the broken-off piece is not too firmly embedded, it can be removed easily. Very small taps and drills can be re- moved at times with a small pair of old dividers, as shown in Fig. 4. If a broken tap or drill can be worked back and forth and yet not be removed, as often is the case, fill the hole with some diluted nitric (about one to five) or etch- ing acid and work the broken part about occasionally. The action of the acid will help free the broken piece, and it soon can be removed. If a lubricant was used in tapping, it will have to be removed with a strong lye solution before the acid can be used with effect. The hole should be washed out afterward with clear water. A large tap that breaks near the surface also may be removed successfully at times by two men’s tapping on both sides with drifts. Both should start hammering at the same time with light blows and in- crease the force of the blows gradually. Seldom can a tap be started by driving on only one side. A TAP sometimes may be broken into small pieces with a punch. When doing this, it is essential to wear goggles to protect the eyes. When the broken tap will not respond to any of these methods, it may be pos- sible to anneal it with a blowtorch or gas flame, when it may be drilled out. Use a drill of tapping size and be careful to start the drill centrally with the hole. Another ‘‘Old Bill’’ article, brimful of practical ideas, is scheduled for next month. It is on the secrets of success- ful thread cutting.

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oN (J mm (Wi eo \w VSS on em YY YF ee em A ONS em eS OT er OD OD OD U2 Oe CD we ‘ | ee ee ee ed et ee i ‘From one who knows INCENT LOPEZ praises and endorses the rich, clear, natural quality of MUSIC MASTER re- production. His Hotel Pennsyl- vania Orchestra is heard over the radio by untold thousands. Even the most delicate and fugitive impulses from distant stations are caught by the precision instrument of MUSIC MASTER hidden in the art metal base. These impulses are developed into full, natural tones, free from blast and dis- tortion, in the tapered tone chamber of heavy cast aluminum—which also im- parts a quality of brilliancy to the reproduction. MUSIC MASTER is an enduring musical instrument. Hear it and see it at your dealer's, or have him send one to be tried and proved with your own set. Dealers Everywhere {Music Master Corporation (Formerly General Radio Corporation) Makers and Distributors of High-Grade Radio Apparatus S. W. Cor. 10th and Cherry Streets Chicago PHILADELPHIA Pittsburgh Vincent Lopes and his Hotel Pennsylvania Orchestra ler RADIO REPRODUCER POPULAR SCIENCE MONTHLY May I say a few words regarding the merits of the Music Master, which to my way of thinking is superlative in its field. For clearness of tone it exceeds any loud speaker which has been brought to my attention, and being directly interested in radio work I consider your product a big achievement and a valuable asset to the radio world. Please accept my heartiest congratula- tions. Sincerely yours, Exclusive OKeh Arti ic Connect Music Master in place of headphones. No batteries required. No adjustments. 87 14-inch Model, for $ the Home 30 21-inch Model, for $ Concerts and 35 Dancing

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88 BETTER SHOP METHODS DEPARTMENT OF POPULAR SCIENCE MONTHLY ‘emington Portable

: c An ideal gift | for graduates N college, in business, and in professional work a knowledge of typewriting is a great advantage. And the possession of a Remington Portable is a decided advantage. . It has every feature common to the big machines. It has the one and only standard keyboard —no shifting for figures—just like the standard office typewriters. It 1s the easiest to learn—the simplest to operate. It is a Remington and that insures its durability and reliability. The Remington Portable is so light it can be carried anywhere, and so convenient it can be used anywhere. And it fits in a case only four inches high. Price complete, $60.00. Easy payment terms, if desired. Sold by all Remington branches everywhere and over 3500 dealers. REMINGTON TYPEWRITER COMPANY Department 67— 374 Broadway, New York THE DE LUXE PORTABLE—A distinctive mode! in Ivery Tone finish, with handsome. brown leather farry- ing case. A limited number are available at $75.00 each. ‘Jhe best aid to self-expression

Laying Out Angles with an Ordinary Combination Square irs your toolkit lacks a high- priced bevel protractor, your trusty old combination square will serve accu- rately enough for ordinary work. Suppose you need an angle of 35 degrees and the distance from the edge of the blade to the end of the combination head Blow the seucce is 214in. Then set may be used the head at the 1 34-in. mark, as shown, rest the too! on a flat surface, and the blade will stand at 35 degrees from the perpendicular. For common angles the distance A (with 214 in. squares only) should be as follows:

525. 7/32 in. 10°- 7/16 in. 15°- 43/64 in. 20° - 29/32 in. 25°-1 11/64 in. 30°- 1 7/16 in. 35° - 1% in. 40° - 2 7/64 in. 45°-2 14 in. 50° - 2 63/64 in. 55° - 3 37/64 in. 60° - 4 21/64 in.

For any angle not found in the table, a simple calculation for the length of the leg for the desired angle will enable you to set the square correctly.—BION R. WIcKs.

Set of Four Extra Angles Speed Draftsman’s Work B* ADDING four homemade angles to his set of drawing instruments, a draftsman can obtain any angle from 1 to 90 more quickly and conveniently than with the protractor usually used. Theextra angles are two of 2 degrees, one of 5 degrees and one of 10 degrees. For or- dinary use they should be about 1¢ in. thick, 5¢ in. wide at the The additional angles narrow end, and 6 or 7 in. long. Used singly, collectively, or in connec- tion with the regular 30/60 and 45 degree triangles, they make possible the solution of any of the more common problems in angular work. For example, two 2-degree angles with a 5-degree angle reversed give an angle one degree from the horizontal. When placed against the square side of a tri- angle, they indicate 89 degrees.—E. W.C. V-Block Rig Aids in Drilling ORILL—~.P7P DRILL BLOCK katy BUSHING 7 rs | 77 —— | | a KP | BUSHING Stee OUck ‘roo gfh WITH "v’stoT_- ¢ > - adeadoe® IN BOTTOM = . CBUSHINGS FOR VARIOUS DRILL SIZES) | emerson round bar stock or pipe is simplified by using the drill centering tool illustrated. It holds the drill so that the hole will be accurately centered. A series of graduated bushings are made to fit the hole in the V-block so that drills of different sizes may be used.

ee : ae Se ee] 2 Sh i auiianel os ma A = 4 4 | mnmemrTmne f o*

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BETTER SHOP METHODS DEPARTMENT OF POPULAR SCIENCE MONTHLY 89 Flat Reamers and Internal Tools Made from Files " A FLAT file often will provide the y material for making a reamer that i is needed immediately to suit a special job. The teeth on the fore end of the file are ground off for a sufficient distance and both sides are made flat and true. Then the taper or shape is ground as A a = F SECTION THROUGH ” TURBINE NOZZLE h : a) REAMER 4 DOG BE B CLEARANCE \ pins . You Men Are Alik : CUTTING EDGES SECTION B-B ca ou en re 1 e€ a SECTION A-A P P ' The tools, ground as indicated, are When I learned what 1,000 men wanted in a Shaving d San Se & ae eee tO Cream, I knew what millions wanted desired. If straight sides are required, a By V. K. Cassady, Chief Chemist , universal grinder can be used. : va The cutting edges are next cut, as GENTLEMEN: ; . ks shown. The sides are ground at right I asked 1,000 men what they most desired in i angles to the faces and the relief is ground shaving cream. . only on the rear corner. This gives the We worked 18 months to perfect for you the ideal m proper angle for a fine finish and prevents shaving cream. We made up and discarded 130 Mi aie te A ceri behind the cutting separate formulas. s edge should be held down to a minimum. After 130 trials, we made a shaving cream which no : The reamer is held on a reversed lathe . : . . 2s ee “ man yet has matched. It excels in lather, in quickness, 0 tool, as indicated. It should lie flat and 7 bilit It ra ays ft fect t | a central with the bore and be properly = mee il ary et bbl ne arter-emects. eXCels “ alined by moving the cross slide in or out. above all, in strong bubbles. Special internal tools for forming the . ¥ bottom of holes can be made in the a a things you wanted ‘8B same way. It multiplies itself in lather 250 Super-strong bubbles sup- 1e times, so a tiny bit suffices for a__ port the hairs for cutting. d ae , shave. No hairs falling down. g. Reclaiming Crankcase Oil It acts in one minute. Within that Th , il - , , , . ti the beard absorbs 15% of e m i a HE oil filter illustrated was devised in el sith adelante niece blend ieee. fine mn. ies southern Maryland garage for re- It maintains its creamy fullness effects. The soap itself is a a claiming oil from crankcases of automo- Si das omlaaitos tie Coou: contemniniie am biles. This oil se is sold to farm- We ask a test 1. ers in the neigh- This is not written to sell you Palmolive Shaving ‘ borhood for use Scan x on mowers, r ; Js LAYERS threshers, and We ask a test at our cost—a ten-shave test. We will l , other rough then accept your verdict. Please, in fairness to machinery. yourself and us, mail this coupon to us. The filter To add the final touch to shaving luxury, we have created Palmolive After consists of a eee Fe -eeeeny ~ men. rary oa show. Leaves the skin smooth 5. gal. cilean, = — ns raat ay ama look. Try the sample we are sending supporte on wrought - iron PALMOLIVE legs about 2 ft. above the floor. SHAVING CREAM EEF nN Three layers of BEF e_aAve><, & The filter is made closely woven . fom # Seal olstm canvas form the 10 SHAVES FREE . filter screen. ‘a These are held in place by a hoop. A pet- Pb a idan obi gt hg om l cock is soldered at the bottom of the can Address for residents of Wisconsin, The Palmolive Company, y for drawing off the filtered oil. The Lys yal rod leute ather can Waconia, Ths Paealen Comm screens are removed occasionally and Lo litgg inl corporation). 360 North Michigan Avekue, re ; : ‘ ed washed in gasoline to remove the sedi- d ment.—A. L. c

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90 BETTER SHOP METHODS DEPARTMENT OF POPULAR SCIENCE MONTHLY ’ Gage Insures Close Accuracy c No.2674—Eveready | in Testing and Fitting Tapers 5-cell focusing - AGING the trueness of a taper by the light with 300-ft. ey : acc visibility method is an accurate and Ja rapid way. This can be done by means P : tw of the simple fixture shown below. po A block is drilled and tapped as indi- “i cated in the upper right-hand corner of lig! this illustraticn and in the drawing on the ee following page. This block holds a pair of buttons at intervals of 1, 2, 3, and 4 in., TAPERS UP TO 8 3" DIAM. CAN BE = = GLA CAGED oe yr a8 aa PR 45 GA F as 52 Syd 18 THOS. [+ | $i 14-I8 THOS 23 COLLAR CAP [1 COLLAR S SCREWS CAP SCREW BOX TOOLPOST WRENCH ‘TO FIT ALL COLLAR CAP SCREWS ta vi: © Tl n your vacation Evereapy Uwit Pi CELLs fit and im- th e prove all makes of —USe Our lashli ht! flashlights. They come e in two sizes to fit or every tubular flash- ; a é f é light case. ; in Put it in the grip for the trip. Near the top. epg ven tye he , . . . ’ size a Ss your You'll use it going, while you’re there, and on the case. Then you can ‘ ‘ ° ° ' ° buy new Eveready pI way back. Synthetic sunlight! It makes night Unit Cells without t . ; ; : ACIS CRC Pos a 0 safe. Wind or rain can’t put it out. Soe origi nce aga a . , Eveready Unit Cell Hundreds of uses, indoor and out. Mountain aa ee Ge ras pl é we = i S20 THUS. Ya-o? THOS. ; or seashore or lake. Use it as a pathfinder after a kigKrs sig dark. Use it for signaling. Use it to investigate vie night noises. Keep it handy. Tie a tape around ; it and hang it within reach. " Better still, take along several Eveready Flash- | i lights—a focusing spotlight for long-range use; a p broad-beam flashlight for close-ups; an aluminum 2 flashlight of pocket size. The newly designed and . improved line is ready—twenty-two fine flash- a yy lights in four general types, for every purpose and ; ee be 2% ‘ purse. New designs. New features. a as aT = See that they are loaded with fresh, strong an” f . . . a” roe \ Eveready Unit Cells—long-lived cartridges of * (io, Saf | °° ° . . ae as rwe 3,” brilliant light. Eveready Flashlights are still it eee a ad . . 6 s : 65 cents to $4.50 complete with battery—any- ia ° “ a | 2 where in the uv. s. A. Buy the improved Eveready haere . . : | ‘ov. 14 Flashlights from electrical, hardware and marine ype supply dealers, drug, sporting goods and general EL eno stores, garages and auto accessory shops. EEE 5" Y my ——- Manufactured and guaranteed by ae , . NATIONAL Carson Co., INc., New York—San Francisco | ype ! Canadian National Carbon Co., Limited, Toronto, Ont. | isn ence ns elie ail dial shea ; ing dimensions that have proved satisfactory ' € " > ] as necessary. The disks are turned and hardened and ground according to the t degree of accuracy wanted and are of the FL ASH LI GHTS proper diameter so that when two lines i are drawn tangent to both disks, they will és B Al ; ERIES lie on the exact taper. The plates on the gage proper, the con- -they last longer ag dong: th Y 9 struction of which is made clear in the : (Continued on page 91) ) pmaee L

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BETTER SHOP METHODS DEPARTMENT OF POPULAR SCIENCE MONTHLY 91 Gage Insures Close Accuracy (Continued from page 90) - accompanying details, are loosened and 2 BI A od placed so that they will be tangent to the na two disks, and the cap screws are tight- f ie ened. _The gage is then placed on the ' QUARTER-INCH of bench ™ aot of a window or an electric light. e taper to be tested is placed in Ce cs the space between the plates. When the PORTABLE ELECTRIC DRILL he 7 | ‘With the Pistol Grip and Trigger Switch”’ = 2 : \ 3 3 5, =a 2 it ry ENCH NUSE urs 5 How the gage is used for checking tapers and testing and fitting irregular profiles taper is correct, there will be no light visible at the ground edges of the gage. These edges also may be covered with Prussian blue so as to leave an imprint on the high spots of the work. Any two disks can be used to give three | or more combinations of tapers by fasten- ing them at different points on the disk 8 holder. The gage also may be used for fitting k profiles. A piece of glass then is fastened | to the face of the fixture in place of the | gage plates; the pieces to be fitted are Bench Drill- ing Stand. The drill can be in- serted or de- tached quickly, by means of handle clamp. $12, Grinding Outfit.— Consists ; of stand which can be fast- In Canada $16 ened to. bench. top, arbor with clamp washers and nat, and gtinding wheel. $3-in Canada $4 placed upon the glass, and the mechanic has both hands free to fit them.—H. S. L. 5" Simply Made Polishing Wheel ’ I ‘he Most Useful | ‘ool . HIS polishing wheel is designed for a t Po ve s; and di ns h The following letter, dated January 30, 1924, was received from 48 ools, punches anc les, and other Howard Vincent O’Brien, Winnetka, Illinois: e 4 hardened steel surfaces. The wheel January 30, 1924, . x proper is turned from a piece of hardwood z — Decker Mfg. Co. ng . . ‘ . . . . a ear ors: Jt} 2 In. thick and 12 In, In diameter, having = The following article was submitted in a competition to a central hole to fit the shaft and a radial ts Popular Science Monthly, and not used. ; ; It occurs to ine that vou might find some use tor it-—-the drill eo in question being a” Black & Decker. "#4 THOS | EMERY CLOTH Very truly, t THOS. | FELT STRIP _ike HOWARD V. O'BRIEN. "€ “T don’t think there can be much argument as to which is the wed most useful of all tools. The kmife is man’s greatest refinement . és upon nature—all other tools are but improvements as to ease and _ speed. “But next to the knife I would place the electric drill. It does more different kinds of work, with less energy and more speed, and with higher quality, than any other tool. “Aside from boring holes, with reaming. counter- sinking, and } even, at a pinch, screw-driving, it is available for simple lathe work in wood or metal. I have even arranged mine for milling, and, with the same simple fixture, for plain and surface grinding. “Slipping a home-made router in the chuck, I have quickly Felt and emery cloth strips are fastened turned out jobs tedious indeed with mallet and chisel. | to wooden wheel with pin and block “‘With the proper table, it becomes a circular saw. And with 1 guides and a handle fitted, it can be used for all kinds of grooving. } : : : “Its portability makes it a family as well as a shop treasure. } slot ending in a hole drilled near the edge. With ph tt and sand-paper discs, wire brush, buffing wheel and A strip of felt is tacked on the outside to Foe everything from scouring pots to polishing door-knobs is easible. > aleaientes cushion for the aid cloth and “And finally, by slipping on a pulley, and equipping it with a the ends project into the slot. A strip of clamp, it becomes a self-contained power plant, available for the emery cloth 2 in. wide and of the same b. — -machine, the — mill, — saecigts —s dias ; : “ is “I am quite sure that no one who has once en) i rd length is laid ov er the felt. 4 blessings, would lightly part with it.” ‘ie A wooden pin and small block are used 4 ved to bind the emery cloth tightly on the om wheel and hold it in place.—F. J. W. Orders and inquiries may be mailed to ill PIPE threading dies should be lubricated . KER Co. . , “THE BLACK & DEC MFG. ; as with a good quality of lard or crude P Sokni ae ee “a cottonseed oil, the lubricant being used 700 Pennsylvania Avenue,. Towson, Marylan in liberal quantities. Ordinary machine oil should never be used.

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BETTER SHOP METHODS DEPARTMENT OF POPULAR SCIENCE MONTHLY Ask Your Garageman When You Stop for Gas! When you tank up with gas Don’t forget—there’s no subs for that long tripask the garage-__ stitute for the Shaler for fixing man about the handy 5-Minute tube punctures because there’s Vulcanizer. He willtellyouthat no substitute for vulcanizing he never dreams of traveling with heat. It’s quicker than country roads without carrying changing tubes—and so much the convenient Shaler foremer- easier than sticking on tempor- gency roadside repairs. Take arycold patchesthat soonloosen atip from him. He knows from and come off. That’s why more experience that vulcanized thantwo million motorists use it patches are the only ones’ andrecommendittotheir friends, that last. How It Works The Shaler is very simple and easy touse. A special Patch-&- Heat Unit is used for each repair. Each Unit consists of a metal pan containing solid fuel, witha piece of raw rubber attached under- neath. Simply clamp a Unit over the puncture, and light the fuel. After five minutes take off the pan and throw it away. That’s all. The tube is ready to use. It’s vul- canized—as good as new. The Complete Outfit includes the handsomely nickel plated vulcanizer and 12 Patch-&-Heat Units (6round for punctures and 6 oblong for cuts and tears) packed in a small Complete Outfit box ready tocarry & in your car foran CostsOnly Mm emergency. All garages, auto ac- $1.50 cessory and hard- ware stores carry the 5- Minute Vulcanizer in stock, Get one for yourcar, C. A. SHALER CO.,2102 Fourth St., Waupun, Wis. Slightly higher in Canada and Far West, | ease-hardened. A Vise Aids in Removing Tage) _o a tap BROKEN has broken TAP & ( Lipp off in a hole and ; ‘ often extracted the tap by placing the smaller than the tap hole in diameter to grip the tap from both ends. When the the character and INS Y size of the work (7mm) (~~ permit, I have HS work between vise PIECES OF SOFT METAL jaws, as shown, and using two pieces of soft steel or brass jaws are tightened, all that is necessary to loosen the tap is to turn the work by hand.—E. E. Lakso, Fitchburg, Mass. Cheaply Made Measuring Points for Large Work A HANDY measuring rod may be made from a discarded broom handle, or any round, hardwood stock, and two wood screws. The point is turned on each screw by holding in a spring chuck; the flats are milled. The points are then The points may have a total movement of about 1 in. Holes should be bored in SIZE MARK, FLAT; = HARDWOOD . a |—— y wood SCREW; , ne ¥g THICK-s oo Fs’ LG ; rma O, TT uf _ i a ie t WRENCH-C:5- CASE~HARDEN-’ CASE=HARDEN Two wood screws with case-hardened points are inserted into a hardwood handle the stick before the screws are turned in and a little soap should be used on the screws. When set to a micrometer, the points will retain their accuracy for an indefinite period, provided the wood used is well seasoned. If they are to be used fre- quently, a small wrench made as shown will be more convenient than an adjust- able wrench for making adjustments. Steel Rail Serves as Useful Straightening Fixture FOUR- or 5-ft. length of steel rail, mounted on trestle legs, as shown, serves as a useful straightening fixture. Heavy legs like those of a sawhorse support the steel rail The legs are made from two-by-fours, strongly crossed, braced, and_ bolted. It will be noted that there is no necessity for drilling holes in the rail, and the fixture, therefore, can be put cs | anes ap toos amth=w . Y as 4 8 of 45 Oe iin i i or together quickly.

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ail, wn, Ire, urs, no ‘ail, put BETTER SHOP METHODS DEPARTMENT OF POPULAR SCIENCE MONTHLY 93 Crowbars and Chains Take Place | of Heavy Wrenches WO lengths of chain and two steel bars, used as shown, will take the place of heavy pipe tongs in an emergency for screwing or unloosening large pipe fittings. The free ends of the chains are held in one hand while the lever is manipulated with the other. Enough turns of the chain are taken to prevent slipping, and to take a new hitch on the pipe it is necessary only to slacken the chains a trifle. This method has been used in dis- assembling iron pumps in which the threads were thoroughly rusted, and it is a useful means of handling heavy work when regular chain wrenches are not available. A File Handle Jack For turning heavy pipe and fittings ge nega need working at the bench | who frequently have to change their files will find that a file jack made | as shown is a time saver. It is made from | a 6-in. length of flat iron 2 in. wide and | is like a miniature bootjack. Slots are provided at each end and the fixture is bolted to the under side of the bench. The tang of the file is slipped into one of the slots and the file pulled out with a jerk. When not in use, the jack is turned parallel to the edge of the workbench. Another method of accomplishing the same result is to insert a knockout rod in the handle of the file. The file then is loosened simply by tapping the end of the rod against the bench. Cheaply Made Shop Roller ITH only standard pipe fittings, a durable and ef- ficient roller can be made for handling heavy and bulky pieces of lumber and steel. It has been used in handling lumber going to and from the saws; for steel bars, for fire hose, and for many other shop purposes.—W. T. M. i, q 3 KNOCK OUT FILE Pt The jack and a handle “‘knockout”’ Erasing Drawing Ink UITE by accident I found that I could erase a commonly used brand of black drawing ink from tracing cloth by applying spirits of camphor. Place blot- ting paper under the tracing and do not rub too hard.—F. N. C. General Motors Trucks Cost of Manufacture Sets GMC Price GMC price represents only the actual physical cost of manufacture plus a reasonable profit—no surplus price camouflaged as trade-in value—no extras. GMC trucks are built from the finest materials by expert workmen and according to a design that provides unsur- passed efficiency and economy. They embody special GMC features which definitely increase their earning gs lessen their cost of operation and lengthen their ives, Yet GMC price is remarkably low in comparison with this unusual service. It is only possible because of economies in the purchase of materials and in manufacturing methods that come through the advantages enjoyed by General Motors Truck Company as the exclusive truck building unit of the General Motors Corporation. Such hauling service at such a low straight forward price is of vital interest to truck buyer and dealer alike. Write for complete information about GMC trucks. GENERAL MOTORS TRUCK COMPANY Division of General Motors Corporation Pontiac, Michigan General Motors Truck Co. Pontiac, Michigan Department 47 Gentlemen: Please send me further information. I am interested in a (truck) (dealership). nea ae

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The Road to Home Though written faithfully, his letters from home seemed to have had a way of arriving at his hotel in one city just after he had left for the next—and of never catching up. Three weeks passed—business conferences, long night journeyings on sleepers, more conferences—with all too little news from home. Then he turned eastward. In his hotel room in Chicago he still seemed a long way from that fireside in a New York suburb. He reached for the telephone—asked for his home number. The bell tinkled cheerfully. His wife’s voice greeted him. Its tone and inflection told him all was right with the world. She hardly needed to say, “Yes, they are well—dancing right here by thetelephone. . . . Father and mother came yesterday. . . . Oh, we'll be glad to see you!” % % # Across the breadth of a continent the telephone is ready to carry your greetings with all the conviction of the human voice. Used for social or business purposes, “long distance” does more than communicate. It projects you—thought, mood, personality—to the person to whom you talk. AMERICAN TELEPHONE AND TELEGRAPH COMPANY AND ASSOCIATED COMPANIES BELL SYSTEM One Policy, One System, Universal Service

BETTER SHOP METHODS DEPARTMENT OF POPULAR SCIENCE MONTHLY

Lace Leg Maker ee /// farer

Breeches Direct from factory to you ;O. D. Khaki, f Duck, Moleskin and Corduroy. Double seat ; double knee ;doub:esewn. Extra belt loop in back. Sportsmen, Campers, Tourists, Farmers, Chauffeurs, Mechanics, Engineers---allOutdoor Men. OUR LEADER, shower proof O. D. Duck Breeches, soft pliable $ 83

BIASCOPE SR Pocket Binocular brings distant objects near on land, on sea or in fabric, made for hard wear. f ‘ Add 25c for reinf the air. For motoring, nature study, every out- Add 8c for — door use. =e ine peepee and inside measure rom crotch to shoe top. $s a $7 at og Besant add 25c. Money- FREE Samples with description of the ack guarantee. irculars free. many styles we make. Money WOLLENSAK OPTICAL COMPANY ne ee ee ester, ee OUT-OF-DOORS Pans <0, the ran Outdoors

—___.. How to Get the Most Out of Your Lathe (Continued from page 80) shaft lengthwise and causes it to bind on the centers. This must be watched very closely, for if the work becomes too tight, the center will get hot enough to twist off and drop the work. It long has been a custom with many machinists to straighten shafting on lathe centers. This is very bad practice and I often wonder why it is continued in any shop. The centers hardly ever will run exactly true after straightening a shaft, and it injures the lathe in other ways. There always has been considerable con- troversy in regard to the proper form for lathe roughing tools and the way they should be ground. However, the efficiency of a lathe tool depends very much upon Fixture to replace compound rest in

sie milling and drilling AS ay operations haa ay FHI siika! Uig=y! ad =)! Hi: be GRADUATE IN ah et DEGREES

its shape and the way it is ground to suit each material. For small variety work, the writer has found tools of a well-known patented type to be the most economical all-around tool. For heavy machine work, forged tools of high speed steel are still the most popular, especially for heavy cuts. A good shape for a roughing tool is shown in Fig. 4. This form has been tested in competition with several other forms and has shown advantages over any others I have seen. One of its particular advantages is its ability to eliminate rapidly the excessive heat generated by heavy cuts and coarse feeds. This length- ens the time between grindings and in- cidentally increases production. Friction aided by heat is what breaks down the cutting edge of a tool. Conse- quently, the more rapidly this heat can be taken away, the longer the tool will last. This tool is so made that heat gen- erated at the point is quickly broken off a short distance away and only a small part of it is retained in the body of the tool. The efficiency of a turning tool also is affected by its position. The point should not be any farther away from the toolpost than is absolutely necessary, and for most work it is best to have the point slightly above the center. When taking very heavy cuts, the tool should be set so that the point inclines slightly toward the tail- stock or away from the cut, rather than in the direction of the headstock. When set in this manner, it will be impossible for the tool to cut under the size set, should there be a tendency for the toolpost to loosen. An engine lathe often may be rigged up with a few simple accessories to turn out manufacturing jobs at a cost to rival that DESIGNED TO SUIT LATHE CROSS COMPOUND

(Continued on page 95) a

— - =e es mh as 85 45 ee

Page 79

er ny lar ite by sh- in- ks se- an vill ta art is ild ost ost tly ary nat ail- in set the ere en. out hat BETTER SHOP METHODS DEPARTMENT OF POPULAR SCIENCE MONTHLY 95 —— How to Get the Most Out of Your Lathe (Continued from page 94) of a high-priced special machine. And it need not be idle when the job is finished, for you always have your engine lathe for general work, whereas a special machine may lie idle for considerable periods. Figure 10 illustrates an unusual method for turning a steep taper on a lathe equipped with a taper attachment so that the power feed may be used. This method is recommended for repetition work. The taper is set by the cut-and-try method. The cam turning job (Fig. 8) shows the possibilities of the lathe as a cam cutter and for other irregular work. The special arbor and tool attachment used (Fig. 9) are designed for manufacturing. HE master cam is a separate piece keyed to the arbor, and the cam blank is fastened on the arbor by a hex nut and washer. The tools are supported by a simple flat casting, which is bolted to the compound rest. This casting is provided with ribs on each side of both tools and at the back, and the tools are adjusted by means of setscrews on the side and at the rear end. Two cap bolts passing through elongated slots in the tools serve to hold the tools rigid while turning. The counterweight arm is made from a straight piece of bar iron bolted to the side of the compound rest. It may be neces- sary to make a short bend in this arm so that it will pass under the arbor. The tool is actuated by the roller, which is held against the master cam by the counter- weight. Figure 5 shows how it is possible to handle a large boring job in a small shop. The job is to bore a hole or several holes, as the case may be, in large heavy castings or similar work. The work may be sup- ported by building a crib of heavy timber or any other improvised method at the end of the lathe. It is leveled up, located for position, secured by lag bolts or some other means, and braced so that it will not move. The boring bar passes through the hollow spindle and carries a collar in which the tool is fastened by means of a setscrew. The bar is driven by a second collar screwed on to the spindle in place of the chuck. The hole in this collar should be a sliding fit for the bar and be fitted with a feather key, which engages a key slot in the bar for'driving. The end of bar is fitted with collars and is held in place by a casting bolted to the compound rest. This arrangement serves to feed the bar toward the work. The end of the bar is supported by an improvised steady rest. HEN cutting threads, it will be found convenient to have the com- pound set at an angle of 60 degrees, as shown in Fig. 7. This makes it easy to remove the tool for grinding and reset it without disengaging the nut, and the thread then is “picked up” more easily than it would be if the compound were straight. In facing off, it is alsoa good plan to set the compound at an angle with the work and lock the carriage. The tool may be fed into the work with the compound, and (Continued on page 96) The New Liberty Twir Our Challenge to other builders to follow us through weeds, shallows and over sunken obstruc- tions has never been accepted and__ still stands. The Only Motor That Gives You 100% Use of Year Boat The Caille Liberty Twin is the only motor that will drive your boat anywhere it will float. It is the only motor that will take you through weeds so thick you couldn’t even row—through water so shallow a boat will scarcely float—over hidden obstructions that will just permit a boat to pass. It’s the only motor that drives your boat well up on shore when landing and can be attached on shore when starting out. It’s the only motor that gives you 100% use of your boat. is the only outboard motor built on the Direct Drive principle. The drive shaft extends straig! te out from the stern of the boat and the motor is pivot:d and so perfectly balanced that the slightest contact with hidden obstruce tions causes it to rise and pass over ‘The propeller of the vertical so-called “ti tilt: ing type” 1 motor receive sa 60- pound blow before it will tilt. Furthermore the Liberty Twin has no bevel gears to wear, give trouble and re- quire packing in grease. Has Bosch Magneto Standard the world over on high class motors. Mounted on a special rocking cradle designed by Caille and Bosch Motorcycle Control Simply turning the grip on the steering handle adjusts the timing of the hot Bi sch spark and cor tro in She Spee of the motor. Pressing but son end of oa engineers, it gives a uniformly hot spark at all speeds. g handle stops motor. . + e Zenith Carburetor Easiest Motor to Carry Specially designed for the Caille Liberty Twin. Oper- The telescoping shaft can be quickly detached to ates automatically at all speeds without any adjustment facilitate c: arrying. Motor ences ches or Ay ‘as a n whatever. No needle valves to fool with. Proper mix- yenjent handles. Can be shi ipped anywhere or carried ture of gas is always assured. on running board of car. Send to Nearest Branch Office for Literature Ask for Measuring Chart to assist you in figuring value of all outboard motors. And remember, whe n y‘ yu buy a Caille motor you get the product of a pioneer in t! dustry—-a ufacturer that is firmly established and wil Ne in busir 1eSs gh the years to come to supply you repair parts s!} hould you ever need them.. Send for details today. Send the coupon to nearest address. E. J. Willis Co., 85 Chambers St., New York City Weeks, Howe, Emerson Co.,90 Market St., San Francisco, Cal. Fremont Electric Co., 736 N. 34th St., Seattle, Wash. James Walker Co., 125 Light St., Baltimore, Md. Leslie Franks, 5100 N. Bernard St., Chicago, III. John J. Odenwald, 1209 H. St., N. W., Washington, D. C. Rapp-Huckins Co., Inc., 57-59 Haverhill St., Boston, Mass. A. Baldwin & Co., New Orleans, La. The Caille Perfection Motor Co. 6240 2nd Boulevard Detroit,. Michigan CAILLE PRONOUNCED “‘CAIL” Rowboat Motors Caille Perfection Motor Co., | 6240 2nd Boulevard, Detroit, Mich. Gentlemen: | Please send me full particulars about the The Single Liberty Proved the superiority of Caille Direct Drive prin- ciple for four years. Just the motor for those want- ing a dependable motor at a moderate ew Caille Libert Twin and measuring chart. | Name WA a Rrateaeae aware area ss Dia ears ase ioy Doma eae te ote Cbahiawheeeeaasaensueeedas ; | Reawonine Breit ety scales alaneras ; hase PSL ee acerca ee cen ce I eg

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% There’s a Deep, Abiding Satisfaction in a Real Good Tool Vichek Valve Lifters The only drop forged Valve Lifters pro- duced. Suitable for all but the cheapest cars. Simple—a turn of the handle slides the cam, increasing the leverage as vs the valve spring is compressed, allowing quick action with greatest ease. Corru- gated, curving jaws—no slipping—springs stay in proper position for a straight lift. Universal action—compresses spring or lifts it up.

Vichek Universal Pipe “ed This handy tool converts your bench Vise => into a Pipe Vise. Or it can be used as a << hand clamp for holding any pipe or round object while drilling or threading. Its iV I), ribbed jaws grip pipe securely. Clamping Cre | | VA Jaw holds round stock, 14 to 34 inches. BS’ ly This tool has many uses and costs very q | \\ i} little. jo SNP | | Vichek Cold Chisels If there is such a thing as a 100 per IS cent all-purpose Cold Chisel, Vichek makes it. Made of Vanadium steel, tempered by the advanced Vichek proc- ess, they are tools of extraordinary quality and life. ‘Tempering is neither too hard to cause chipping or soft enough to cause the edge to turn. Cutting edge / is oversize—added strength, greater cut- “ 7 K F Vv ting surface. Vichek Bearing Scrapers Every scraping edge has a high spot. non-chattermg. Polished blade, ebony Forged from high grade tool steel and hol- | shank, black finished handle. Sold in sets low ground, with sharp edges. Positively of three.

Write, giving us your dealer’s name and we'll see that you get the tools you want, THE VLCHEK TOOL COMPANY 3001 E. 87th Street 33 Cleveland, Ohio EASY TO SAY VELCHEK oVLCHEK TOOLS MADE BY THE WORLDS LARGEST PRODUCERS OF TOOL KITS SOUSA “WONDER” COLD PIPE, TUBING & BAR BENDERS tells you the secret of Standard of the World HAND and MOTOR hese Success in Music in this Free Book.

14 Sizes of Machin What it costs to bend rae our Hae Si pene

Send for

Send for bh soealeg your copy and details of i ws silo 2 pipe 10, cents é <4 50 om of FREE TR m Y SK ay pipe $1.00

PAYMENTS on any Conninstrument for band or orchestra. Ac- claimed best by world- ous artists. G. Conn, Ltd. 632Conn Building Elkhart, India:

AMERICAN PIPE Senarne MACHINE CO. 51 Pearl St. Boston, Mass. Tool Cases for Machinists, Car- penters and Tool Makers; none better; thirty styles. Quarter- ed oak and metal cov- ered. Ask for booklet. **Built for Service’”’ The Pilliod Lumber Co., Swanton, Ohio

BETTER SHOP METHODS DEPARTMENT OF POPULAR SCIENCE MONTHLY

Thick and Thin Line Device Added to a Ruling Pen OPEN POSITION FOR * ii LINES - i CLOSED FOR . Pe LINES iaailaiaaiaaia LEVER —e/ —- HEN a draftsman has to do cross- sectioning that consists of light and heavy lines or a large amount of con- ventional line shading, he will find it pays to use on his ruling pen the special attach- ment illustrated. This is set so that the pen normally will draw a thick line, but when the lever is pressed lightly with the forefinger, the pen closes for drawing the thin lines. A common type of cleaning catch used on some ruling pens can be used for the same purpose.—W. A. P.

Repairing a Large Bushing HAVE repaired bushings for the spindles of an automatic multiple spindle screw machine in the way illus- trated, which is also useful for renewing badly worn spindle bushings of lathes and other machines. Cut four longitudinal slots in each end of the bushing as indicated. In this case

Renewing expensive machine bane the slots were 4 in. long. Two short bush- ings then are made of any suitable ma- terial and pressed on the worn bushing to compress the metal sufficiently to allow it to be rebored.—JOHN LARSON.

How to Get the Most Out of Your Lathe (Continued from page 95) the face will come out much straighter. The engine lathe is capable of perform- ing many milling operations, such as cut- ting key seats in shafts, milling square ends, slotting screwheads, cutting small gears and the like. The fixture shown in Fig. 11 (page 94) is attached to the saddle in place of the compound rest and will be found useful for many jobs of this char- acter. A set of V blocks may be used for holding shafts and other round work. The fixture is also useful in drilling. In regard to drilling in the lathe, it is worth noting that practically any kind of a job that the drill press will handle may be done in the lathe, but this is not to be recommended except in a small shop.

NOTHER article on the lathe is scheduled for early publication in the Better Shop Methods Department. It will give a number of lathe short cuts that frequently can be used to save time and labor.

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ross- light con- pays cach- ; the but 1 the r the ning n be the tiple illus- wing sand end case ush- hing low of hter. orm- cut- uare mall m in ddle ll be har- 1 for The it is d of may o be luled Shop nber used How to Make the Most of Parallel Clamps ARALLEL clamps often can be used to advantage in holding work on the bench for fitting or laying off and in —ff> BENCH RIGGING FOR PARALLELCLAMPS Wg THIS CLAMP HOLDS Yfyfpes THE WORK CLAMP ON THE BENCH Holes through bench permit use of parallel clamps in the two ingenious ways shown fastening small parts in the most con- venient position and the best light. By boring several holes in the bench top, one or more clamps can be used as shown in the upper illustration. To hold small work at the edge of the bench, one clamp grips the work while the other clamp fastens down the first, as indicated in the lower drawing. Non-Slip Guide for Automatic Screwdriver Speeds Up Work N ATTACHMENT for use with an automatic screwdriver, which will greatly speed up the work and prevent slipping of the blade, can be made very simply. It consists of a sleeve to fit the tool, a peg fastened to the blade and SLEEVE PRESSED BACK SPRING HOLDING SLEEVE OVER SCREW With this guide, the automatic screwdriver blade immediately enters the screw slot sliding in a groove in the sleeve, a small spring to keep the sleeve projecting be- yond the end of the tool, and a peg against which this spring bears. When the sleeve is placed over the screw head and pressure is brought to bear on the handle, the end of the blade quickly finds the slot in the screw head and the screw can be driven home. The spring allows the sleeve to slide back upon the tool when making the last few turns. —WALTER T.MARKOWSKI, Camden, N. J. HEAvyY sheet brass may quickly be re- duced to paper thickness for thin gaskets, shims, and the like, by dipping it repeat- edly for a few seconds at a time alternately into nitric acid and then into water. p { . SON RY eh np Ore = Pe MY eg IS as ba a ghy 2 2 Oe ea ee oe in Wle- $4 = he a LEE B Pitt Aw 1\ 0h SSS ee =Sh = mS —. m fF Xu Se eo oe oe a 8 | is ix Zn ju ee | heey eye (4p. A EEE Z Anew Magnavox that will broadcast satisfaction fo the radio world CHere’s big news ‘on the air” Requiring no battery The supreme achievement of Magnavox engineers repre- sented in a Reproducer of truly exquisite tone quality. ¢ | HE efficiency, the appearance and the price of this new instrument clearly re- flect the research and production facilities of The Magnavox Company, largest builders of radio reproducing equipment in the world. Its exquisite tone quality results from the perfection of the Magnavox semi-dynamic operating principle incorporating; first, a new magnetic- ally balanced armature; second, an improved type of diaphragm supported by hollow rubber gaskets; and third, an extremely high resistance winding which makes M4 unusually sensitive. ducer capable of operating without a battery, M4 is indeed supreme. Beautifully finished in dark enamel with gold high lighting, the graceful appear- ance of Magnavox M4 suggests its use in Magnavox Meand other Magnavox Radio Products can be had of good dealers everywhere. THE MAGNAVOX CO. Oakland, Calif. New York Office: 350 WEST 31st STREET Canadian Distributors: Perkins Electric Limited Toronto, Montreal, Winnipeg the most dignified surroundings. Equip- ped with five feet of flexible cord and Weston plug ready to connect as simply as a head set. The amazingly low price of this Magna- vox Reproducer establishes an abso- lutely new standard of value in the radio industry. For those who desire a Repro- ———— ay a — varia an ate MAGNAVOX a The Reproducer Supreme ic’ : ee a me Rete Re Aaa a nen hn at NTR at ata genet 9 = e a ee ee ee SS

Page 82

Makes mean jobs easy . , : Unscrewing an old hose clamp, or screwing tight a new one is an ees job unless you use “YANKEE’ Quick-Return Spiral Ratchet Screw-Driver No. 130 A (Improved No. 130) It does the work for you. All you need to do is to place it in the screw slot of the clamp bolt and push. The live spring in the handle shoots the handle back quick for the next push. Its long reach prevents barked knuckles. Right-hand and Left-hand ratch- ets and Rigid Adjustment. ‘Three sizes of bits. No. 130 A, Standard size (Im- proved No. 130). No. 131 A, He avy proved No. 131). No. 135, Lig! “Yankee” Spiral Ratchet Screw- drivers, without the ca return feature, No. 30 A, No. 31 A, No. 35. Some Other ‘‘ YANKEE” Tools Ratchet Breast Drills Ratchet Chain Drills Ratchet Bench Drills Ratchet Tap Wrenches - pattern (Im- 1t pattern. Dealers everywhere sell ‘‘Yankee’”’ Tools Write us for Free “Yankee” Tool Book that shows “Yankee” tools in action. NORTH BROS. MFG. CO. PHILADELPHIA, U.S. A. “YANKEE” TOOLS . Make Betliv Mechanic BETTER SHOP METHODS DEPARTMENT OF POPULAR SCIENCE MONTHLY ! to within .005 in. Accurate ‘‘Wiggler’’? Rod for” Use with Indicator 1 le LINE up punch marks when setting work to be bored in the lathe and | milling machine, a “‘wiggler’” rod with indicator is an invaluable aid for accuracy inserted in the center punch hole in the work while the other end turns on the tailstock center. Any movement of the rod as the work is turned indicates that the mark is off center. The work is then gradually brought into line. By amplify- Details of the rod and how it is used with an indicator for centering work accurately ing the rod movements with the indicator, accurate results are certain. The rod may also be used in a milling machine by holding a center on a line with the punch mark on the work. The work is then brought in line in the same | way as for lathe work. The spring must be sufficiently strong to hold the ends of the rod firmly against their seats. There must be no lateral play of the end slide in its hole and the end centers must be truly on the axis of the rod, with no rough spots on the surface of the rod that would cause false movements on the indicator. Hook on Oilcan Spout Lifts Spring Dust Caps NNECESSARY soiling of the hands while oiling the generator, starting motor, and other parts of gutomobiles can be avoided to some extent by using the tip of the oilcan to lift the spring caps over the oil holes. Part of the metal at the tip of the oiler spout is filed away and the remainder is turned over to form a_ hook. This hook will hold up the lid while oil is injected into the hole.—G. L. ag ~-METAL FILED AWAY '""'Oilcan spout hook For cleaning brass castings an effective solution is made by mixing sulphuric acid, three parts, and nitric acid, two parts. A handful of ordinary salt should be added for each quart of the solution. The mixture must, of course, be kept in an earthenware receptacle. The point of the rod is | The Best Seller in the Ford Field Salesmen find Fil-O-Meter {n- creases their earnings over 100%. Manguson made $48.00 in one day; Laux, as a side line, cleared $56.00. Already territory is completely closed in some states. Line up quick with this big money-maker. Clamps into tank opening A Gasoline Gauge and Filler Combined fills Ford gas tanks without raising cushion. Gas Gauge always within driver's sight. Basic patents. prevent all competition. Weighs 2 pounds. Attaches to any Ford in. ten minutes. $$ Retail—Big Profits This handsome _ instrument retails at $5.00 (open cars), Fills Tanks without removing cushion $6.00 closed models. (Add 50 cents in West.) You make a liberal commission and are given sales help such as local advertising, circu- larizing, printed matter, etc. Gas Gauge Territory Closing Fast always in Now is the time to get lined plain sight . pada nued Fer com- ete plans, sales help, ete. Dealers? On receipt of $1. oo deposit, Sal p sample esmen$ fo, palance of Distributor's Write or ao’ Wire A. J. KIRSTIN CO. Today? 1151 Virst Street. Escanaba, Mich. ere a. ee ee ee en ol Statement of the Ow nership, Management, C irculation, etc., required by the Act of Congress of August 24, 1912 of Popul: ir Science Monthly, published monthly at New York, N. Y., for April 1, 1924 State of New York, County of New York, ss. Before me, a notary public, in and for the State and county aforesaid, personally ap- peared H. J. Fisher, who, having been duly sworn ac- cording to law, deposes and Says that he is the publisher of Popular Science Monthly and that the following is, to the best of his knowledge and belief, a true state- ment of the ownership, management, etc., of the afore- said publication for the date shown in the above caption, required by the Act of August 24, 1912, embodied in Section 443, Postal Laws and Regul: itions, printed on the reverse of this form to wit: 1. That the names and addresses of the publisher, editor, managing editor, and business m: inagers are: Pub- lisher, The Modern Publishing Company, Inc., 225 West Thirty -ninth Street, New York, N. Y. E ‘ditor, Sumner N. Blossom, 225 West T hirty-ninth Street, New York, | A Managing Editor, Sumner N. Blossom, 225 West Thirty- patee Street, New York, N. Y. Business Manager, O. B. Capen, 225 West T hirty- ninth Street, New York, N. Y. 2. That the owners are: The Popular Science Publish- ing Company, Inc., 225 West Thirty-ninth Street, New York, N. Y. Stoc kholc de rs of Popular Science Publishing Company, Inc., Henry J. — 22 William Street, New York, N.’Y.; Oliver B. ‘apen, 225 West Thirty-ninth Street, New York, N. Y Robert Cade Wilson, 683 Springfield Avenue, Summit, N. J.; George B. Agnew, 22 William Street, New York, N. Y.; Susan D. Bliss, 22 William Street, New York, N. ¥.; L.. B. Tunison, 6 N. Michigan Ave., Chicago, l.: A.L. "Cole, 225 W. 39th St., New York, N. "Yo: Godfrey Ha .mmond, 225 W. 39th St.. New York, N. Y. 3. That the known bondholders, mortgagees, and other security holders owning or hold- ing 1 per cent or more of the total amount of bonds, mortgages, or other securities are: none. 4. That the two paragraphs next above, giving the names of the owners, stockholders and security holders, if any, con- tain not only the list of stockholders and security holders as they appear upon the books of the company, but also, in cases where the stockholder or security holder appears upon the books of the company as trustee or in any other fiduciary relation, the name of the person or ye rey for whom such trustee is acting, is given; also that the said two paragraphs contain statements embracing affiant’s full knowledge and belief as to the circumstances and conditions under which stockholders and security holders who do not appear upon the books of the company as trustees, hold stock and securities in a capacity other than that of a bona fide owner; and this affiant has no reason to believe that any other person, association, or corporation has any interest direct or indirect in the said stock, bonds, or other securities than as so stated by him. (Signed) H. J. Fisher, Publisher. Sworn to and eniaed before me this 10th “day of April 1924. w.w a Brown, Westchester Co., N. Y. Co. Clk’s 844- (Sex al) Ny Commission expires March 30, 1926. $25.00 in Prizes See top of page 8 in front of book for full details

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Ameen OO BETTER SHOP METHODS DEPARTMENT OF POPULAR SCIENCE MONTHLY 99 Building a Turret Attachment for a Small Lathe By Joe V. Romig This is the last mechanical design of importance made by Joe V. Rcmig for POPULAR SCIENCE MONTHLY. It was completed shortly before his death and forwarded to the Editor through the courtesy of Mrs. Romig. HEN a small bench lathe is used for light manufacturing, a turret is almost invariably necessary. With an automatically operating turret and six tools in position, the work time can be cut toa minimum and duplicate parts quickly and accurately machined. Turret attachments for small lathes, however, are expensive. If the lathe owner desires, he can save much of the ex- pense by building his own. The design illustrated makes possible the construc- tion of an accurate and long wearing turret. Standard cold rolled steel shapes are used, eliminating much of the other- wise costly machine work. By using a lever feed in connection with the automatic turret, the turret is shifted with a minimum of effort and in the LATCH SPRING, LATCH PIN. , STOP PLATE--~* STOP BAR-- BY * GUIDE 8 . SECTION A‘A : igscrew BAR GUIDE i STOP PLATE } | STOP BAR OO aly. : Views showing how attachment is assembled shortest time. Shifting mechanisms usu- ally are complicated, but the one in this design is both simple and effective. While the dimensions given in the ac- companying details are for a 6-in. attach- ment, the sizes may be altered in correct proportion for a lathe of any size. Assuming that the lathe to be fitted has a flat shear, the builder works up the turret base, using a piece of 14 by 4 by 5 in. stock, to which he steene the side angle plates shown. These plates reach up above the base, so as to allow the em- ployment of the adjusting screws, which aline the side guides, operating on the tur- ret side. The plates are shaped on their inner surfaces and should be straight and true. They are held to the base with three cap screws on each side. The guide members are of 34 by 14 in. stock, 5in. long. The top hates are 3/16 by 13/16 in. stock, 5 in. long, and the assembly is made with four 1-in. flat head screws on each side. The holes (Continued on page 100) There? ¢ 4 double HHere's an Stfea Btn, armhole that double elasticity in the Hanes webbing belt. It’s 2-thread instead of single. Sewed especially to prevent rips and tears, , “can’t curl or . rip—large, 4 ° roomy and fric- tion-free, 5 Bi This button re- ‘A (\ fuses to come off. \. It’s sewed to the “Sa seam. Four thick- nesses of material instead o} the usuat two. No patch. 2 Talk about comfort! The Hanes closed crotch stays closed. It’s cut and stitched in a special way to in- sure comfort, © es W 3 \ A wide, full- length knee that won't creep up your leg—won’t bind! Money can’t buy greater summer comfort OUR money never went further than when you put it into Hanes Athletics. Such comfort, freedom and coolness. Look over the Hanes points shown above. Here are five reasons why men everywhere have come to the conclusion that it “pays to say Hanes” and have stuck to it. The end of the summer will tell the story of Hanes value. - Pull Cut Wash-day after wash-day, ATHLETIC UNION SUITS rough and ready summer wear —Hanes still looks, still feels, still fits the same. Absolutely every stitch, thread and button is guaranteed. Go to your dealer and say “Hanes.” Feel the fabric. Examine the workmanship. ‘The price—a dollar—can’t be matched. Hanes for youngsters too. And how they wear! Boys from 2 to 16 years—sizes 20 to 34. Read this guarantee: We guarantee Hanes Underwear: abso- lutely—every thread, stitch and button. We guarantee to return your money or give you a new garment if any seam breaks, P. H. HANES KNITTING CO., Winston-Salem, N. C. New York Office, 366 Broadway Nowe Wanker Wear Nanos eles Undebatinr GERSTNER CASES give perfect satisfaction be- cause they are made right, Teshnabers and Machinists and other particular me- chanics find them of great value because they keep their tools free from rust, dust and damage, A style that will just suit you is shown in our free awe: te for H. GERSTNER & SONS 506 Columbia St. te rah 0. on id For Our Just the outfit you nave always 4BOO0OK A rea! professional baseball ane BARGAINS ABSOLUTELY FREE bodi es and accessories at 6 pe. ou’ consists of: baseball! sult, excopticnslls low fj Cap. git * Fielder" "a ploves live league . direct be baseball, Catcher’ Riva factory. ir i Rush Such reer mame for Free Baseball AUTO TIRE beeed SALES CO. \ RELIABLE SALES CORP. 7 Dept. } s. > i 434 Broadway "i York City a Eee resin

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100 BETTER SHOP METHODS DEPARTMENT OF POPULAR SCIENCE MONTHLY 17 YEARS Without Repairs It looks as if H. L. Westbrook, of New York, holds the long-distance record. He has been riding an I ver Johnson bicycle 17 years without spending a penny on repairs. And yet that is the sort of service every Iver Johnson is built to give. The I ver JohnsonTruss-Bridge construc- tion assures absolute rigidity, preventing give and sway of the frame, during fast pedaling, pushing up hills, or through sand. Also made in Drop-Bar models. The high carbon seamless steel tubing used in Iver Johnson frames and forks has a tensile strength of 90,000 pounds to the square inch! Fork crowns, cranks, fork- ends, handle-bar stems, seat posts, and other parts are of genuine drop-forgings made in our own plant Iver pane Bicycles are made to fit all sizes of men and women, boys and girls. Colors: Ivory Black, Copper aa Poilu Blue, meet oe mk Msc Blue, and Maroon. Every model is finished with five coats of enamel hand rubbed, and all nickel plating over copper. Best guaranteed equipment. Write for Free Booklets Catalog ““B”’ “sang line of Iver Johnson Bicycles, as well as ver Johnson Velocipedes. Catalog ‘‘A”’ illustrates and describes the com- plete line of Iver Johnson ‘“‘Hammer the Ham- mer’ Safety Revolvers, as well as Iver Johnson Champion Single Barrel Shot Guns and Ham- merless oo Barrel Shot Guns. DEALERS: We sell Bicycles and ~necime Aha direct to re- tailers. A golden opportunity is = to handle this famous line. rite for DEALER PLAN. IVER JOHNSON’S ARMS & CYCLE WORKS 5 River Street, Fitchburg, Mass. New York: Chicago: 151 eines St. San Francisco: 717 Market St. IVER JOHNSON BICYCLES illustrates and describes the com- ° 108 W. Lake St. 3 "i a cold rolled steel 34 should be aecked carefully for straight- ness and parallelism, using a straight edge and micrometer. stem is drilled and counterbored, as shown, and toward the rear end is later fitted the bearing plate of the indexing slide. WASHER «, PIVOT POST. simple. fastened to the top of the base by one of the four rear screws. This latch is pressed in toward the slide by a flat leaf spring, held under the central cap screw, the spring operating on the hump of the latch. A stop pin limits the inward travel of the latch and holds it in the proper position to receive an indexing pin on the rearward movement of the slide. follows: ward, the latch engages with a pin, as shown, and stops the travel of the slide. Continued pressure and movement of the handle compresses the spring and with- draws the indexing finger, at which the turret slide again moves backward, re- volving the turret, until the stop on the front, side engages another index pin. All rearward motion of the slide then stops. A forward motion of the handle causes Building a Turret Attachment for a Small Lathe (Continued from page 99) drilled {n the side guides for the passage of the screws are made large enough to allow adjustments. The turret slide is made from a piece of 4 by 3 by 934 in. This A hole for the pivot The turret proper, 3-in. diameter, is turned as indicated. The central hole is reamed to fit nicely over the pivot stem. A clamp handle and washer hold it tightly to the slide, when necessary. spaced holes are drilled and reamed for the six 5/16-in. indexing pins, which must be a snug driving fit. of high grade steel, hardened and drawn to a brown color. Equally These pins are made The indexing finger is made from a flat piece of steel, turned down at one end to a> CLAMP NUT ‘ Ui Ys LW A TURRET SLIDE | abe nupe GUIDES p>— 2" “a5” i STOP PIN.-’ 46 How the turret is made and mounted é-in. diameter. Over this part is slipped a fairly strong spring. The finger at the other end operates through a square guide, the fit being snug though free. The forked end of the finger is flared to make the entrance of the pin an easy matter, and case-hardened to prevent wear. A flat steel handle, 14 in. long, is attached to the indexing finger and connected with link to a small bracket at the rear of the slide. The shifting mechanism is extremely A latch made as detailed is The action of the shifting device is as When the slide is moved back- (Continued on page 101) with the EB Super-heterodyne Manual é Biggest Value in construction aid ever offered! Victor Greiff’s big text book complete and three full-sized blue prints,—tells how to build 3,000-mile, loop Super-Hetero- dyne. Order today. 7’. RADIO RECEP" Dept.S 57 Banks St. New York Magnified 225 Diameters This is what the tip ofa fly’s leg is like when seen thru the Wonderful New Ultralens Microscope At last the high powered micro- TS 50 scope is within the reach of all who wish to study, observe and experi- ment with the vast world of minute objects that are invisible to the maxed eye. aa ait lg ny amateur can immediately * start using his Ultralens to examine Outfit Prepaid the edge of a razor, the mesh of a cotton shirt, the bacteria in dirty water. No _ technical training re- quired yet hundreds of scientists and teachers are using this in- strument today. It is at once interesting, instructive, and scien- tific. Gives enormous magnifica- tion and hg pg a rder direct from this Order Today advertisement and get your Ultralens Microscope now. Fully guar- anteed. If, however, you desire more information before purchasing, we will gladly send free descriptive catalog, SCIENTIFIC APPARATUS CORP. Dept. 207 MILTON, PA, BROS. & CO. fai8 . Seae Watches, etc. = oo aid for your FREE ieee jon. atalog explains everything. Money back if not satisfied. ty °F 18-K Solid Whit Gold, 17. 29.7 14-K Solid avis Gold: 163. $24. 33 WEDDING RINGS mee, Bismonds: Thee Diamonds: > ened ve oR $95; se; y Biamonds, Sirs: mond Surround $0 iby z Diamonds $425, 25. — ite or Green LOFTIS B BROS. | & CO. ‘National Jewelers 108 N. State St., Chicago, lil. an a in Leading Cities ll adj exc dri! wil hal pu 2yY — s&s, = ws" OO —- fo Gols Ste CP

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» a cee ee BETTER SHOP METHODS DEPARTMENT OF POPULAR SCIENCE MONTHLY 101 How to Make an Adjustable Boring-Tool Holder fy BORING holes in jigs and accurate experimental models, the 54 to 2 in. adjustable boring-tool shown will do excellent work. It may be used in a drilling, boring, or milling machine. This tool consists of two main parts made of machine or tool steel. Tool steel will be more satisfactory, but pack- hardened machine steel will serve the purpose. To make the shank part, a piece 214 or 214 in. in diameter is turned as shown 4¢ HOLLO' W = SETSCREWS > ECCENTRIC STUD PIN LWS GE Details of a tool-holder useful in boring tholes in jigs or other accurate work and an eccentric hole is located, drilled, and reamed to receive the eccentric stud on the other part. It is then drilled and tapped for a setscrew. The taper shank is made to correspond with tapers used in the shop. The tool-holding part is chucked off center enough to allow the eccentric stud and face to be turned. This stud should be a nice running fit in the corresponding hole. A recess 5/16 in. long by 7/16in. in diameter is turned on it so that it will not be bruised by the pressure of the setscrew. The first part is inserted in the lathe spindle and the second, after being placed in position and locked with the setscrew, is turned and bored for the central tool hole. It is also drilled and tapped for the tool-holding setscrew. Hollow head setscrews are recom- mended, although square heads may be used.—H. L. W. Building a Turret Attachment (Continued from page 100) the indexing finger to engage its proper pin and locks the turret in its new position. After the turret is assembled, the last operation is to bore the 14-in. tool holes. A center drill is chucked in the head spindle, and the turret is revolved in its six positions. The holes then are drilled 1/32 in. under size, and are bored and reamed to the exact size. If the index pins are not exactly spaced, each pin neverthe- less will aline accurately its corresponding hole. The tools are held by setscrews, which should engage with a flat on each tool. Each flat should be equal to one quarter the diameter of the tool shank. The travel of this turret, which is 4144 in., is ample for any operation on a lathe of 6-in. swing. In radio the Neutrodyne is the ultimaté fot selec- tivity and clear, true reproduction, as well as for power and ease of operation. THOMPSON NEUTRODYNE means the best radio principle plus the engineering skill of an organization that has been building radio and wireless apparatus for over fourteen years, The Tuompson is a factory-built—not an assem bled—5-tube Neutrodyne. What this means to you can be demonstrated by any good dealer. Price $150 without tubes or batteries. THOMPSON MAGNAPHONE is built upon an entirely new principle that gives purity of tone in any volume—yet no battery cur- rent is needed. The THomPsoN MaAGNAPHONE is $35 at all good dealers. R. E. THOMPSON MANUFACTURING CO, Manufacturers of Wireless Apparatus for the U. S. Army and Navy and numerous foreign governments 150 NASSAU STREET NEW YORK, N. Y. * FACTORY: JERSEY CITY, N. J. Licensed under Hazeltine Patent Nos. 1,450,080, 1,489,228 and other patents pending permed HON Oe Aiwa Ua snig De A py ‘ [ar SEND FOR THE International Body Werks, ATIQNAL CATALOG RN Our net price list. auto bodies and accesso- ries for Fords at Wholesale Prices. Save big money on Fuil line of FREE D pace fae FREE Also wholesale prices on : Track and Base Ball Equipment inal eae Base Balls Syst." $1.35 pair F FOR FORD—Prices from $27.85 up. _ Factory to consumer direct—Pay only One Profit 914 W. Ohio St., Dept. 8, Chicago, Ill. 27 innings American Sporting Goods Company Jacksonville, Ill. SHAW Motor A MAKES YOUR BIKE A MOTORCYCLE! to an The Johnson Folding Pocket Rule is made of Spring Nickel Silver, accurate- ly and distinetly graduated. It can be used as a Square, Hook-rule, Caliper: guage, Protractor, Triangle or Tri- square, and can be applied to practical- ly all classes of mechanical work. Ver- nier reads to one-half degree. Center Joint has fibre bearings which will not become loose and will remain firmly at any angle. No. 46--6/ Rule $2.50; No. 45--12” $3 50. Including chamois cases. Money refunded if not satisfied. Catalogue on request. G) E. P. JOHNSON RULE MFG. CO. 565 W. Washington Bivd., Chicago, ti. a

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a The helper you need for a hundred uses VERYBODY is _ building these days. Millions are making RADIO SETS. You need a vise to hold your panels, your coils, your wires while you are soldering, and for many other purposes. something It’s time now to overhaul the CAR. While you are filing, grinding, polishing or doing the scores of things every motorist has to do in the Spring, you need a vise and you can do more work, faster and more easily. It’s hardly necessary to tell the FARMER, MACHINIST or HOME BUILDER, that they need a vise. They know it! And they know that the vises they can rely on ab- solutely are those with a half century of service behind them—the famous PRENTISS VISES A model for every need; a vise with every desire able improvement.

If you want an exceptionally good “all-around” vise for general use we suggest the popular “Bull Dog” design here illustrated. Our new booklet is ready. Write for yours today. Fill in and mail the coupon now. PRENTISS VISE COMPANY 106-110 Lafayette St., New York City Gentlemen: Please send me your latest booklet describ- ing PRENTISS VISES and including prices. My nameis . re ee PROS 6 CPC OSE oO TODOS Ce SOON ODOD Oe £8 °000000066 WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY

Building a Shaper for the Home Shop HE useful little By Frank N. Coakley shaper illustrat- ed is a machine that most amateur machinists would like to own. And, unlike many handy machines they could make and would make but for the expense, it may be built with materials that are easily obtainable at a reasonable price. Expensive patterns, so often the stumbling-block of the home mechanic, are not needed. Since the majority of home machinists own lathes, the lathe is utilized to provide the power for running the shaper. This is done by transmitting the motion to the back the same as the front end and 5-in. holes are drilled to hold the pin for the two flats that act as a connecting rod between the short lever and the sliding bar. Al by 1°{ by 2% in. steel block is drilled, tapped and filed to act as a tool- holder. The toolpost is the same as ordi- narily used on lathe or shaper. The adjustable work bed is made up of standard material. The main support is a 2 by 2 by 14 in. angle about 6 in. long, securely fastened to the wooden members with 8 14-in. lagscrews. The vertical leg has 3 5-in. countersunk holes drilled in it to provide fastenings for the

END OF BAR -~--~a MNOT LESS THAN _ nae 4 up-and-down feed base. } “ pie This base is made from a6 * 1 ae) = by 6 by 5% in. angle about PINe he © 8 in. long and is provided Foes... _ a with 3 slotted holes to

TOOLPOST .-- BS BS

3-4gB0LTS,

allow for the up-and-down adjustment and also to hold it in place against the 2

won ie soe ~ See by 2 in. angle. This ar- a os I aoe es | Tangement allows the use ee: Ee : m\ a-B0LTS-" of a sliding plate to which Downy Te 6. ie eagle Soziale ances! is fastened a standard vise pncie-soe-4e eee j _. smeous ; of the type illustrated. 4-4 HOOK BOLTS y The vertical adjustment

HOLD DOWN PLATE"! “ADJUSTING SCREW WHEEL %° BOLTS’ Side view of the shaper attachment, which is driven by a lathe faceplate sliding bar through a connecting rod from the lathe faceplate. The connecting rod is made from two pieces of 54 by 2% in. flat brass, riveted together and forked at one end (see detail B) to fit over the outside lever. This lever may be purchased from any manu- facturer of drop forgings, but those who are on a friendly footing with the village blacksmith possibly can get him to hammer out both levers, just to keep in trim. The sliding bar is 114 by 4 in. flat steel about 141% in. long. The front end is made as indicated at A to take the tool- holder, which, while a snug fit, must be not so tight that it cannot rise on the return stroke. The side members, made of 134 by 5 by 18 in. oak, are grooved or rabbeted on their inner faces to provide sliding ways for the bar, and also shaped as shown in the side view. Angles 1144 by 1% by % in. are bolted to each side of the assembled side members to take the hook bolts that hold the attachment down on the lathe. The width of the angles is governed by the width of the lathe bed. The side members and the two oak separating pieces are dovetailed together and held by four %-in. bolts pulled up as tight as possible. A short length of 34-in. cold rolled steel in two standard 34-in. bearings serves as a pivot for the levers, as in detail D. The sliding bar is held down by a 3¢- or5¢- in. steel plate fastened with 12 14-in. lag- screws. A 3/16-in. brass strip (see C) is fastened to the under side of this plate with small countersunk stove bolts, or, better still, copper rivets, to prevent any chance of steel rubbing on steel. The rear end of the sliding bar is cut OAK: 1349518 is obtained through a 34-in. 1x4 FLAT STEEL, Vg BRASS STRIP ~. YSTEEL PLATE ~~.) | 12g LAG SCREWS}, 1 BRASS BUSHING ~__ CONN. ROD HEAD ~. *s. BRASS WASHER -~ 4 fF no Son | % PIN- TO SUIT-- FT 2 “Ghd

EE ag FLATS, 5 | ‘f % PINe=., a) Y \ Vis ~y ded eet 2 eI pat Saad aad Co BEARING " ¥=--°" 'D // ie OROPEFORGED LEVERS..--" 4 CRS Details showing wooden ways, sliding bar, top plate and arrangement of cranks screw; the horizontal movement is reg- ulated by a screw fastened to one end of the sliding plate. The handwheel may be obtained from a junk dealer and the handle tapped into the rim or left off, at the option of the builder. The pin used to drive the sliding bar from the lathe faceplate can be made from a piece of cold rolled steel. The head should be at least 1 in. larger in diameter than the pin proper. This is pulled against the rear side of the face- plate. The body of the pin is of proper size to pass through the faceplate slot. A brass bushing is made to slide over the body of the pin; it should have a flange large enough to prevent the connecting rod from rubbing against the faceplate. The body of the pin being somewhat shorter (say 1% in.) than the bushing, allows the pin to be clamped up tightly to the faceplate. A brass washer is placed between the nut and the bushing; this prevents the connecting rod from rubbing against material of its own kind. It will be well to go over all surfaces that rub or fit against other surfaces with a file to finish them smoothly. Before assembling the machine, soak (Continued on page 103)

Page 87

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HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY 103

Removable Screen Door Latch T IS often desirable that a screen door should be locked against small children and yet provide free entrance and exit for older folk. The latch illustrated does this. The main member is formed of a thin and fairly wide metal strip, bent as shown to suit the thickness of the screen-door frame. Cut a slot through the frame just inside the stop against which it strikes and quite high. Use a small drill bit to start the slot and work it to the required length with a keyhole saw. Drive a nail into the edge of the frame to act as a pivot pin. Have the latch so balanced that the weight of the hook end will cause it to engage quickly the latch post on the main door frame. This post may be a short, round-headed screw, turned wellin. The latch may be removed by lifting it straight up and over the pivot pin.—L. S.

| SAWED SLOT

Latch is above reach of the children

Telltale for Basement Light OW often have you forgotten ‘to turn out the light in the cellar? A simple and yet cer- tain reminder can be —\ made by cutting a CELLAR LIGHT’ small hole in the kitchen floor under the sink or in any convenient, out-of-the-way place and inserting a piece of thick glass.—O. M. A.

GLass/——~/ 7}.

Building a Shaper (Continued from page 102) the oak well with oil along the surface on which the sliding bar rubs. When this is once done, it will not be necessary to oil the surface for along time. A grease cup is placed on the top holding-down plate to provide lubrication between the brass strip and the sliding bar. The two levers, which are keyed snugly to the 34-in. shaft, and the two 34-in. bearings can be lubricated with grease cups on the under side of the bearings, or through oil holes drilled at an angle through what will be the upper side of bearing. Keep all moving parts well oiled and tight. A machine like this should last for years with proper handling. While I have given no dimensions for the lathe- bed and the fastenings, it will be under- stood that these will be governed by the size of the lathe. This also limits the stroke, although on an 8 or 9 in. lathe the stroke should be 4 or 5 in. Some one may ask: ‘‘Has this machine a quick return stroke?” No, it has not; why should it? This feature would complicate the design and, as amateurs are not working under a boss who wants as many pieces of work-done as possible, we can dispense with the quick return feature.

aS, KRAEUTER C00. SI A Ss ———— ——_— ZX SSS = ——_ en ———— —S—_5 —S Needle Nose Side Cut- ting Pliers, = — —= S<— = x x Sx LZ—S 4a y ha VSS Slip Joint Pliers with SIDE CUT- TERS, No. <i)

<4) = ~~ SO Me a) =< LE =

a =< g) Sa ZZ

Electricians’ | Side Cutting Pliers, No. 1831,

= ——_ as |

Umbrella Tent—No 7 CAMP IN 5 IY BY Center COMFORT (Pat. Pend.) “OUTDOOR” Auto Tents embody patented features found nowhere else. Made of Highest Quality, Close Count specially woven drill; absolutely water-proof, mil- dew-proof and shadow-proof. Umbrella Tents have sewed in floor cloth; come with or without center pole: can be equipped with Cot Transom (pat’d.) Combination Picnic Outfit Lunch in comfort on Lawn or in Camp, Con- vertible into full double bed. Table folds to carry outfit. Nothing like it anywhere. a WRITE TODAY for complete cata- log of Tents and Camp uipment ‘| ~sent FREE.

rite for Taxidermy Book. Tella all about 4 rtsman, r an y eee Merde should know this wonderful fascinal art. i Low ny ng Save sour trophies. Big ‘e te. guaranteed, 75,000 rad- Rerthwestera School of Taxidermy 4-178 Bheeod Bids,; Onska, 3 | United States Tent & Awning Ca Edward R. Litsinger, Pres. ou,

718 No. Sangamon St. hicago

NS - Se ee

Page 88

104 HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY Ask the Best Niechanic in Most Any Garage about Snap-on teen anand INTERCHANGEABLE Socket Wrenches INE times out of ten he’ll say, “Sure, I use ’em my- self. Best tools I’ve got, too! Save a lot of time and extra work, and make good money for me when I’m do- ing piecework.”’ You couldn’t want any better recommen- dation than that for tools to use on your And there are car. over two hundred thousand mechanics in the United States who feel just that way about Snap-ons. Snap-on Kits are hand picked for in- dividual cars; see your dealer or send us the name of your car, and find out how reason- ably you can get Snap- on service. A handful in a Kit to service your car individually Motor Tool Specialty Co., 14 E. Jackson Bivd., CHICAGO Gentlemen Please send me full particulars about Snap-on eee car. (If interested in Master Mechanic’s Kit, check here............ ) 8S See ee a ere DDL i vckwes es eee ss ineeeekeh ee pees e seers Log Used as Light Roller for Lawn and Garden LIGHT roller for lawn and gar- den may be made of a 3-ft. section of a log, in this case white pine, about 10 in. in diameter. The frame, which is constructed from scraps of old lumber, is 3 ft. 6 in. long and 21 in. wide. The whole contrivance weighs about 60 pounds. The cost is nothing ex- cept the time to make it.—L. B. Making Cheap Window-Screens Give Long Service N OCCUPYING a new house, the question of- window-screening arose. After careful comparison of cost and lasting qualities, it was decided that full- length screens would be best. Wooden frames were made of 1 by 2 in. pine, mitered at the corners, screwed together, and painted white. Galvanized screening was used. It was painted black as soon as it was fastened to the frames. Our home being near the seacoast, the salt air soon would have rusted out ordinary black screening. Bronze, although desirable, was barred on account of cost. The screens are now three years old, and in excellent condition. A yearly ap- plication of black screen enamel is made where the galvanized wire, by showing the color through, betrays the wearing of the old coat. This, indeed, is the secret of our method. Black wire, when wearing, gives no indication, as the metal rusts and turns black as soon as the enamel is off, and galvanized wire does not show deteri- oration until the rusting has actually started, when it is sometimes too late, but the combination of enamel on galvanized wire is good.—R. C. TARR. Olid Piston Useful in Heating Soldering Iron Rapidly oo a soldering copper is held over the open flame of a blowtorch, a great deal of the heat is wasted. A faster and more economical method is to use an SUPPORTING BOLT Piston prevents waste of heat from blowtorch old auto piston to conserve the heat, as illustrated. Saw a small slot diagonally through the skirt of the piston so that it will take the shank of the soldering iron. Then mount the piston horizontally at one end of the workbench by fastening a bolt through one of the wristpin bearings.—L. B. R. MAKE MONEY-SELL RADIO! Radio offers the biggest money-making op- portunity on earth today. And the Ozarka Plan opens the door to this big opportunity. Look at the picture of this beautiful Radio Receiver. This picture was made from an actual photograph. By the Ozarka Plan that Radio Instrument can be the product of your own making—easily, simply and sure- ly. It will be yours to make, to sell and to reap a rich reward in cash profits. No experience necessary. You need not have much cash. All you need is spare time, de- termination and action. If you’re that kind of a chap, the Ozarka Plan will start you on a straight line toward a real money-making business of your own. It can be as big and as profitable as you are ambitious to make it. We want good men in every county. Ex- clusive territory is going fast. Be sure and give us the name of your county. Write to- day for the Ozarka Plan. A wonderfully in- teresting book of facts, particulars and proofs. Itis FREE. Act now. OZARKA, INC. 852 Washington Bivd. CHICAGO ——JIUST OUT DUSTIN’S 5 RADIO Post LOG AND Paid CALL BOOK —— \ new tee It fe worth dollars and dollars to you. Contains list of all broadcacting stations in U. and Canada, giving call, owner, location, oe watts, wave length, freque ncy kilocycles. 20 pages of log for keeping record of stations received and dial reading for future reference. Contains Dustin's National Radio Map. The only book of its kind on the market. By mail only. Sent postpaid to any address in the U.S. or Canada on the receipt of 25c. DUSTIN’S RADIO LABORATORIES, Detroit, Michigan. | AWA Al AN rtaR WAIEANS Dot After ner FIRST LESSON You Will Play a Complete Selec- é. tion. We Guarantee That-- ry Our method is so simple, interesting and appealing that you begin in your first lesson to learn the famous Ha- ee waiian Folk Song** ALOHA’’. Think G3 how happy you will be when you . surprise your friends by playing the ‘fascinating Hawaiian Guitar. Only Four Motions-- and You Master Them Quickly! ‘In a few minutes you acquire the four motions necessary to play an plece--after that ashort period of practice and you will have mastere this weirdly sweet music, Complete course of 52 lessons includes FREB Guitar, y picks, steel bar, etc. Noex | No Previous Musical Knowledge Necessary If you never read a musical note in your life--if you haven’t even the Siemon knowledge of music, we can quickly a E positives y teach you to play this wonderfull, popular instrument. t be just a ‘‘listene er’’ when you can easily be the center of interest 4 rb ied. your frien Over 40, 300 successful students. Just Mail a Post Card for Details of our remarkable FREE Hawaiian Guitar Of- fer--simply write: ‘‘I am interested’ iz E but do it today. First Hawaiian Copcoryatesy A Beautiful Hawaitan Guitar Vislin, courses on} Desk46 233B’dway olin, Tenor-Ban- (Woolworth Bldg.) 30. Banjo Ukulele} New York City Loe oe

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—s—<—<—_—

ee

HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY 105

——————— Blueprint Will Help You Build Neat Telephone Table OULD you use a telephone table and stool in your home? Then why not build it yourself with the aid of PopULAR SCIENCE MONTHLY’s Home Workshop Blueprint No. 18? Louis Bergstrom, of DuBois, Pa., used that blue- print in con- structing the table and _ stool illustrated. He writes: I used fir, stained a dark oak. The grain of this wood shows up very beau- tifully in this colored stain. Every one who has seen it says that it makes a most attractive piece of furniture. The table top is 17 by 21 in., Made by Louis Berg- large enough to strom, of DuBois, Pa. be used, when necessary, as a writing table. Besides the swinging tele- phone stand, there are racks for sta- tionery. Beneath the top is a compart- ment for the telephone directory and drawers for index cards and writing materials. If you wish the complete working de- tails and bill of materials, use the coupon below to order Blueprint No. 18.

Complete List of Blueprints AY* one of the blueprints listed below can be obtained from POPULAR SCIENCE MONTHLY for 25 cents. The Editor will be glad to pro- vide, upon request, information rela- tive to tools, material, or equipment. Blueprint Service Dept. Popular Science Monthly 225 West 39th St., New York. GENTLEMEN: Send me the blueprint, or blueprints, I have underlined below, for which MANCIOSE.. 5.06 Ges cents: No. Title Price IRTP 2a! 2c) «| | 25c 2. Smokme Cabinet.............. 25c 3. Book Trough End Table........ 25c 5. Kitchen Cabinet....... ey i 6. Two-Stage Radio Receiving Set. .25c 8; SHAVING MO BOINEL. . o.oo 25¢ 9. Arbor with Gate and Seats..... -25c UR Se Se 25c 11. Bench and Tilt-Top Table....... 25c 12. Electric Washing Machine....... 25c 13. Tea Wagon. + woe 14. Toy Train, Horse, and House... 25¢ 15. Home Workshop Bench........ 25c¢ 16. Inlaid Radio Cabinet........... 25¢ 17. Cedar and Mahogany Chest.... .25c 18. Telephone Table and Stool...... 25¢ 19. Grandfather’s Clock............ 25c ZO; DIGG FOr LeeSe. «o.oo 5 5 ie a sso cee 25c 21. Colonial Writing Desk.......... 25c 22. Girl’s Cabinet and Desk......... 25c ZS. TROIS SGOT ORE, 6.0 os oe cece ee se cROe fC ES RS | 25¢ 25. Sailing Outfit for Canoe.........25c 26. Baby’s Crib and Play Pen.......25c 27. Kitchen Cabinet Work Table... .25c 28. Pullman Play Table.......... Sc 29. Toy Tea Cart, Garage. etc...... 25¢ 30. Tool Cabinet, Bench Hook, etc. .25c 31. Priscilla Sewing Cabinets........25c 32. Chinese Game Table............ 25c 33. Pullman Dining Alcove......... 25¢c 34. Trellises for House and.Garden. .25c

| Speed Your Sawing | stock. Dadoes 1” wide x 114 ee | table. Attachments for sand-

“Look at That Workmanship!” A striking feature of the new Eisemann Receiver isthe unusual interiorconstruction. No confusing array of criss-cross wires— just a group of fine instruments so arranged and co-ordinated as to give the utmost elec- trical efficiency. The wiring—and there is little of it—is in- visible. All leads are short and direct, thus eliminating causes of interference and im- proving the quality of reception. All of which reflects engineering skill of a high order. ASK YOUR DEALER Descriptive Literature on Request EISEMANN MAGNETO CORPORATION ( William N. Shaw, President \ 40 Thirty-Third Street Brooklyn, N. Y.

$25.00 in Prizes See top of page 8 in front of book for full details

ar ed —— -

We have positions open now that will pay from $45 to $100 a week. We are organizing a sales force to introduce the Cole Visible Gasoline Gauge, @ low-priced, scientifically accurate in- strument for Ford and Chevrolet cars. Prevents running out of gas. Guards against short measure. Fits on instrument board—always in sight. Big selling records. iz ° MAKE $50 THE FIRST WEEK We want one man in each coun- fasiine Jame ty. Our campaign is just begin- ning. Capital is not necessary. We help you start. Ter- ritory going fast. Write to THE STEMCO ENGI- NEERING CO., 11g Webb St., Dayton, 0.

Do sawing, dadoing, boring, and sanding on this low cost machine. Get to making prof- its with the Boice-Crane “Utility” Saw Table 16x20". Saws 2%” deep. Table’ elevates for grooving. Horizontal boring ing, grinding, and face-plate turning. Motor 1/3 to % h.p. Machine sold as illustrated or without motor and base for bench mounting. Write for information on Bench Saws, Jointers, Tenieacty Band Saws and W.B. & J.E.Boice, 2785 8 Norwood pm, Ono PAT. 99-13; S1-1R% 7-16-18, 10-19-20 I)

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A Better Saw for Every Use For every man who buys or uses saws, there’s an Atkins saw to do the work easier, quicker and better. Here are a few of many popular Atkins saws. If dealer hasn’t the ones you want— and we will see you are supplied. your “Write Us, No,400 HAND SAW. SHIP POINT

Finest saw made in quality, workmanship and _ finish. Genuine SILVER STEEL BLADE, Ship point, 26-inch length, five gauges, taper ground. MIRROR POLISH. Solid ROSEWOOD HANDLE. Improved Perfection Pattern. Skew or Straight Back. No.53 HAND SAW

SILVER STEEL blade, taper ground, given Atkins exclusive Damaskeen Polish. Improved Perfection Handle, which elimi- nates wrist strain. Cuts fast and easy. Regular or Ship Point Pattern. JUNIOR MECHANIC HAND SAW __z

A new saw for the Boy Scout and radio mechanic. Handy for home use, too. Made 20 in. long, skew back, nine points, taper ground, highly polished; cherry handle, mission stained. No.!0 HACK SAW :!

Hard rubber handle, ‘‘easy grip’’ pattern; hung low, thus directing full stroke to cut- ting edge. Steel frame is nickeled, highly polished; adjustable to 8, 9, 10, 11 and 12- inch blades. No.3 NEST

This set includes 12-inch keyhole blade, 14- inch compass blade and 18-inch special interchangeable nail-cutting blade, in adjustable handle.

Booklets FREE “Saw Sense’”’ shows Atkins wood-cutting saws, tells how to file saws and gives helpful facts on building. ‘Saws in the Shop” shows our metal-cutting saws, and contains many money-saving suggestions. To get the booklet you want, write your name and address on this page and mail to us. E. C. ATKINS & CO., INC. Makers of “Silver Steel” Dept. D-20 Saws and Tools Indianapolis, Ind.

| | | Pin _ Weier Fasten Small Pulleys Firmly to Shaft By Howard Greene FTER a good deal of experience, satis- factory and otherwise, the writer has adopted the method here described for keying small pulleys on their shafts. It is easy and mechanically good; it holds the pulley well and has the further advantage | that when used for keying a pulley made | of true. hie of thin material without a hub, it keeps it stiff and true on the shaft. The key is a simple round pin passing | diametrically through the shaft, its size depending, of course, on the size of the | shaft. Mark the location of the pulley on the shaft, and locate the hole so that it will just be covered by the pulley, the edge of the hole and the face of the pulley coming on the same line. Cut a groove in the face | | or hub of the pulley deep enough so that | the pin or key will lie snugly in it, but pro- jecting the merest trifle above the surface. Get a washer, or make one, with the hole the same diameter, approximately, as the shaft and drill it, and drill and tap the | pulley for four countersunk screws. This completes the construction work. To assemble, put the pulley on the shaft, slip the pin into the hole, bring up | the pulley so that the pin goes into the groove,

Simple method for keying small pulleys that is particularly useful for the amateur mechanic The washer pinches the pin to the pulley and holds it securely, and if the pin is a good fit in the hole, the key will never give any trouble. Where the pulley is of such thin ma- terial that it will not hold true on the shaft without additional support, the pin provides just what is needed. In such a and screw the washer in place. | case, however, particular pains must be | taken to have the hole for the pin exactly at right angles to the shaft and to have the | groove for the pin of equal depth from end toend. Otherwise the pulley will run out | Even then, however, matters be mended by letting the pin a little can | deeper into the groove at one end than at | the other. If the pulley is exceptionally thin, it can be supported still further by using two pins, one on each side of the pulley and at | right angles to each other. Only one need | be held by a washer, but the second pin must be snug and tight. One of the advantages of this arrange- ment is that it is much easier to remove a pulley than if a pin is passed through hub and shaft. Simply remove the screws from the washer, push back the pulley and pull or tap out the pin. Obviously, gears | can be mounted in the same way, although | in mounting gears it should be remem- | bered that a slight wabble that would not | | affect the work of a pulley would make a gear noisy and inefficient and cause it to | wear unevenly.

HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY ~in 90 Days No other instrument is so easy to play as the sweet toned Saxophone, In one hour you can play the scale, in a few weeks play popular tunes and in 90 days take your place in Band or Orchestra. True Tone SAXOPhHOne is Easy to Play—Easy to Pay, Favorite instrument of most of the great artists. We give 6 days’ trial in your own home. If satisfied, you can pay for it on any of our terms to suit your convenience. Same offer applies to Buescher Cornets, Trum- pets, Trombones, etc. Saxophone Book sent free on request. Write for it today. BUESCHER BAND INSTRUMENT CO. Everything in Band and Orchestra Instruments 3148 Buescher Block, Elkhart, Ind. —— —— a am 1 Buescher Band Instrument Co. 3148 Buescher Block, Elkhart, Ind. Gentlemen: | I am interested in the instrument checked below: | Saxophone Cornet... Trombone _. Trumpet... Mention any other instrument interested In)

WA HINGTON COAL © ime eet Con ‘Exchange Buildin E

ARTISTS EARN BIG MONEY (©3303 Turn vour talent into money. We can teach you drawing in your home during spare time. 1° Well-trained artists earn from $40 to $200 a week. Thousands of publishe rs and advertisers need the work of good artists. The MODERN METHOD is an easy way to learn to draw original pictures. Write today for full particulars showing opportunities for you. State your age. MODERN INSTITUTE OF ART 7 East 42nd Street, Dept. 46-A New York City A $500 Cash Prize is offered for the best second verse to “I’?LL BE WAITING” Those wishing to compete may receive a free copy of this song and rules of contest by addressing EQUITABLE MUSIC CORPORATION 1658 Broadway, New York City

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C4 4 3 ; ¢ ‘ 2 ys isv to hone, scale, tunes ice in

phone Write NT CO. ruments id. ae | | below: |

HOD is an Vrite today ou. State ? rs need the | iT York City 7 e rize erse to i ive a free yntest by ZATION City

a — HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY

Adjustable Drawing Board Mount for Desk or Table pok mounting a small drafting board on the desk or table of the home draftsman, the method illustrated has many advantages. The board can be ad- justed to any desired angle and when not in use can be swung against the wall out of the way, so that the desk can be used for other purposes. Another feature is the shade roller for protecting the drawing from dust and preventing it from fading or blurring when temporarily laid aside. Two slotted uprights of 114 in. by 14 in. cold rolled steel are stim with wood | SHADE ROLLER ) fq) By 4 KNURLED bBINDING NUTS

Owea 4 DRAWING- 6 BOARD

When not in use, this board stands at the back of the table screws to the surface of the desk near the rear edge. If the desk or table upon which the board is installed is placed against the wall, the uprights will not be obstructive. To the top of these uprights are riveted the brackets that hold the shade roller. Attached to both sides of the drawing board are hinge pieces each having a 3¢-in. hole by which the board is attached to the cold-rolled rod that protrudes from the uprights. A check nut and a knurled binding nut are provided at each end of this rod.—C. M. WiLcox, Torrington, Conn.

Filing Small Lathe Tools UTTING tools for small lathes made from 14 or 5/16 in. steel are some- times unsatisfactory because the faces and edges are slightly rounded in grinding. This interferes seriously with good work. An excellent way to make such tools is to file them up from soft steel (annealed tool steel), using small, fine-cut files for finishing. Then bring them to a smooth finish on the oilstone. Harden and tem- per them in the usual way, and finally clean them up with a little rub on the oil- stone. It will be found that it is easier to keep the edges correct in this way than by finishing after hardening, and it is also less trouble, because it is easier to work the steel before hardening. Also, the best part of the steel is the surface skin, which

grinding removes. ‘= ceiivial

POPULAR SCIENCE INSTITUTE

A pprover ‘BONNEY ‘CY. WRENCHES Here is the newest thing in open end wrenches—wrenches made of Chrome-Vanadium Steel—the toughest, strongest steel made. What using C.V. Steel in wrenches means to you. Up to now,.Chrome-Vanadium Steel has been used for automobile springs, and similar products where an especially fine quality steel is needed. Now, you can have wrenches made of this wonderful steel. The Bonney C.V. Wrench is light in weight; has thin, finely tapered jaws that makes it possible to get into tight places; and will fit practically all the nuts on your car. | ~ ) 2 a,

> ~. We are so sure that you will find these wrenches the finest and most beautiful tools you have ever seen, that we are making this Special Offer. Send $5.00 (add 85 cents if you want the sturdy leatherette roll) and we will send you the kit illustrated, containing 6 C.V. wrenches with 12 dif- ferent size openings. If, at the end of ten days you are not thoroughly satisfied return the wrenches and we will promptly refund your money. This is our guarantee. Our dealers make this same guarantee. BONNEY

CHROME-VANADIUM CHROMIUM for toughness acidiiniaeniainidld for strength Sold by Auto Accessory Stores and Good Hardware Dealers BonNEY Force & TooL Works Cedar Street . S. Patent Office

4

(TRE To RNER BRASS WORK ) : The World’s Largest Exclusive Manufacturers ( HANDIEST TOOL * in the House Siotted Dozens of jobs 4" '"e around the y house can be ‘tended to’ quickly and thriftily with this super-blow torch. Eleven valuable _ fea- tures have been built into this master tool by e mine nt torch engineers. For any purpose where intense heat is required nothing can take the place or do the work of the TURNER mOTORCH Sale asa Candle

flared Air Inlet iustavie Separate Needle Valv@ Indispensable in every home. A necessity ; in every workshop or garage. And so per- ARKS Cabinet Shop Special is the fectly safe that even a child can operate it last word in portable, small shop — be Se a Ge i. be equipment. Ss ow ore « oric i ° ? tae tear ot utility companies in America It is a band saw, shaper, lathe —all in have adopted it as standard equipment. one. You can do sawing, rabbetting, Use it whenever or wherever you wish. planing, moulding, matching, panel rais- Use either gasoline or kerosene. The ing. Just the thing for your home shop! famous Turner intensifying baffle gives You can order it complete or with just perfect gasification always—and a flame 400 degrees hotter than the torch you fear to use. Comfortable, pistol-grip handle; Safety Valve; sturdy, leakproof tank. Absolutely troubleproof and fool proof. You're handicapped without a Turner — get one today. If your hard 25 ware dealer can’t e supply you write ee direct to us. postpaid

Wells St., Sycamore, Il. of Blow Torches, Fire Pots and Brazers <O5yr" eee the: Trade Mark registered v4

Allentown, Pa.

it’s a Wonder! Does Everything in Woodworking i Only $225.00 i) — complete with motor

8 inch Circular rip saw 8 inch Circular cross cut saw 11 inch Band saw 4 inch Jointer Shaper 10 inch sander lathe =14 inch swing the attachments you want. Write for circular The Parks Ball Bearing Machine Company 1547 Knowlton St., Cincinnati, O. Canadian Factory: 200 Notre Dame East, Mentreal, Can. PARKS =| | betel pegeyl repants WOODWORKING MACHINES

Sameengs ee remaeat —— el

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108 Paint up Clean up HEN the whole world is smiling and _ everything around you is fresh and clean and beautiful—then it’s time for you to take a hint from nature—Paint Up, Clean Up. The Car If the old car seems a bit dingy, then get busy. Just a couple of hours of your time, a_ small amount of Lowe Broth- ers Automobile Varnish Color and you'll think twice before you trade-in your car. Porch Furniture Then there’s the porch furniture. After being stored away all winter it deserves a fresh coat of paint. A coat of Lowe Brothers Automobile Var- nish Color will effect a magical transformation in its appearance and provide a finish that will retain its freshness for several years. Linoleum Maybe the linoleum in the kitchen is showing signs of hard usage. If such is the case Nep- tunite Floor Varnish will brighten up its faded colors and give it a new lease on life. Everything And there’s the flower boxes, the screens, the front porch, in fact, lots of small jobs that you can do. For whatever painting you may have in mind there is a Lowe Brothers Product specif- ically made for that work. Go to the Lowe Brothers Dealer in your town. Tell him what you’re going to do. He’ll make a lot of valuable sugges- tions and will supply you with a paint, varnish, enamel or stain noted for its beauty, durability and economy. The Lowe Brothers Company Factories: Dayton, Ohio Toronto, Canada Branches in Principal Cities Cue Dect PAINTS & VARNISHES Large Homemade Grain Scoop Has Handle on Top ‘yee as grain scoops are, farmers will find it pays to make their own scoops of the type illustrated. A large scoop with the handle at the end, as cus- tomary, is unhandy and cannot be used conveniently in cramped places, but one with a handle over the center saves effort. Scoops can be either half round in sec- tion or square, for use in bins with square corners. Medium gage galvanized sheet iron is cut to the shape desired and drilled WOODEN HANDLE- —>—~ = yy x STRAP IRON y ,u / In ss 48 * 12 . Half-round and square-bottom grain scoops, showing two methods of fastening the handle for the small nails that hold it to the back board. Oval handles, of straight grained wood, are fastened by a single screw to the rear board and held in front by a 1¢ by 14 in. flat iron brace. Two methods | of making the brace are shown. The grip { | | | can be improved by wrapping the handle | with stout twine from end to end. Making a Forked Rod End from Plain Tubing | | | HE forked rod end illustrated makes | a good job for small, light work. Either brass or steel tubing may be used, although it is not always easy to obtain small tubing in steel. The first step is to flatten the end for a length a little more than the length of fork required. This may be done neatly by inserting a solid rod in the tube up to the point where the flattening is to begin and keep- ing it there while flattening. File away the A simple rod end for light work edges of the flat- | tened portion until the wall is cut through. A piece of flat steel can then be inserted between the separated jaws and a light | hammer used to finish the flattening and provide the proper amount of separation. It remains only to trim to shape, clean up, and drill for the pin. Unless the tubing is heavy, the bearing surface will be small, but to some extent this can be compensated for by the use of a large pin. A rod to connect with this can be made in a similar way, except that the flattening is carried further to | make a fit between the jaws. A variation | can be made by partly flattening the | whole rod.—H. G. To BEND copper tubing for gasoline lines | without its kinking or cracking, fill the | pipe with melted resin and allowit to cool. | HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY Free Blueprints of Money-Saving Hook-Ups Ask your dealer for valuable free blueprints of Dubilier Duratran radio- frequency hook-ups. If he has none write for them to us and give us his name. ; Don’t throw your one-tube re- generative receiver away because you can’t get the distant stations. These free blueprints will show you how to add a stage of Duratran radio-frequency amplification and bring in all the stations within range no matter what the wave-length may be. You save the ten or fifteen dollars you would spend for new parts if you follow the free Duratran blueprints. The Duratran amplifies uniformly twenty times on all broadcasting wave-lengths and with all standard tubes. All good dealers sell the Duratran. Price $4.00. Dubilier Condenser and Radio Corporation 40-42 West Fourth Street. New York. N. Y. The MONARCH Jr. Lathe Ideal for Beginners or Experts The MONARCH Jr. 9” Engine Lathe (illustrated) is simple and trouble proof—beginners soon turn out finished work—the choice of experts too. A splendid lathe for inventors, mechanics, small shop owners. Compact; completely equipped; accurate, semi-quick change gear; auto, satety devices. a 9"" lathe— (a )) 2). ft. bed— REY with bench legs Also built with bed lengths up to 5 feet. Made in ll-inch swing size too, at slightly higher price. THE MONARCH MACHINE TOOL CO. 401 Oak Street SIDNEY, Ohio Life-size paper patterns — You canbuild $8 -— small cost! We are manufacturers and our quantity production enables us to quote exceptional low prices. Our unique shipping methods save you 73% in FREIGHT CHARGES. Send onee for free particulars on Central Bodies. Our Book: ‘*HOW BUILD A FORD RACER’’ sent anywhere on receipt of 25c in cas TE TODAY tamps. WRI CENTRAL AUTO SUPPLY CO. Dept. 122, LOUISVILLE, KY. Y? st scien all tt are | far bat Lae | YEge Sse ———— sil eet es oe et A et et ©

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free dio- one his use ons, you ran and nge nay lars you ts. nly ard , N.Y. ee the erts trated) 2 turn 00. A small lipped; rate; quick > gear; safety 10 1e— d— n legs ‘ade in price. . CO. Ohio UNDER SLUNG PARTS Pes ie , “6° oduction ee 4. HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY OU may havega good receiving set, but if your headset is not scientifically constructed it takes all the joy out of reception, You are sure of good results with a Stromberg? Carlson RADIO HEAD SET because the coils are layer wound and layer insulated and the mag- nets very powerful. - U4 Powerful magnets give sensitivity 4 necessary to long distance reception. Layer wound and layer insulated coils ensure standing up under high voltages. Ask your dealer Stromberg-Carlson Tel. Mfg. Co. 1060 University Avenue , Rochester, N. Y. The balance in easy monthly payments. The famous tudebaker 21 Jewel Watch—Insured fora lifetime; 8 adjustments, including heat, cold, hronism and 6 positions—choice of WRITE 64 new Art Beauty Cases. Direct from the maker at lowest prices. Send today for wonderfulStude- Fine Chain FREE! taker'Boor'ot BIG SPECIAL OFFER. Besntiful focal ye | whain FF EE wi th every watch. ae Down Offer Studebaker Watch Co., Dept. 236 South Bend, Indiana DRESS UP $3.85 YOUR CAR AND UP Aseedy looking top spoils CUSTOM MADE its appearance. Get a Liberty Custom Made Top. It’s fun putting iton, simple direc- tions furnished. Save a big labor bill. We are manufacturers of tops, side curtains and seat covers, for any make or model car. Amazing values. Special proposition for Fords, Chevrolets, Dodgesand Maxwells. Write today for bigmoney saving catalog BERTY TOP & TIRECO., Dept. E-8 Cincinnati, Ohio Motorcycle Bargains cf SAVE 25% to 65% yy, on Slightly Used and_ Rebuilt or isa Otorcycles, Ace, Indian, Excelsior, Harley-Davidson, Cleveland, Side : Cars, Johnson Motor Wheels, Evans , oe Power Cycles, Bicycles. Send for ai DB’ d Free Bargain Bulletin § and "| LB fa3"| Money Saving Message, listing, Oe 8 : hundreds of bargains in used, rebuilt and new machines, supplies, accessories, etc. AMERICAN MOTOR CYCLE CO. Dept. 626 2047 W. Chicago Ave. CHICAGO Swinging Tray and Pocket Add to Armchair’s Utility OMETIMES we must hunch into that old armchair and concentrate on some problem with the aid of books, paper, pencils, ink, drawing tools—inspired by peppermints or a dried-up plug. Such a chair should have a wide arm, with a ditty-box hinged underneath, as How a tray is attached to chairs | with either wide or narrow arms illustrated. The writer has a cigar-box | about 114 in. deep, swung on the flap of | a 5-in. strap hinge. There is a suitable hinge for any size and shape box desired. A loose-pin butt will permit the removal | of the box if its contents are required at | the bench. Between the side posts you can make room for a paper or book pocket, built with thin board stock. Let the bottom be 3 or 4 in. below the seat, and the inner side open about level with the seat. Case the outer side to the arm. A box ean also be fitted under the narrow arm of a “best-room”’ chair, as indicated in the smaller drawing. This arrangement will interest a woman, for the box is a handy place for sewing accessories, writing materials, and odds and ends that nobody likes to leave a comfortable seat to fetch. A table without a drawer may be fitted with one or more of these boxes, for the larger strap hinges will support con- siderable weight.—ROLAND B. CUTLER. Baby Carriage Tire Forms Finger Grip for File End NY one who has much saw filing to do knows how sore the fingers of the left hand become. I have tried wrapping the end of the file with tape, as well as ‘ using a cork and block of wood, but the best protector so far discov- ered is a piece of baby-cab tire. It will not creep off the end; it can be changed instantly from one file to an- other and it forms a firm soft grip for the fingers. In making it, I find that a piece 1 in. long, rounded on one end, is the most satisfactory. This can be obtained, sometimes merely for the asking, in almost any furniture or bicycle | maop—8. A. McLEAN, Denver, Colo. RUBBER | FINGER GRIPs._ ---> A file accessory | that costs little | | | 1 109 F you buy good tools, the kind of tools that give long- lived, sturdy service, then it’s Klein Pliers you will want for your kit. The steel, tem- per, design, and balanceof Klein Pliers are the result of sixty- seven years of manu- facture of pliers. Klein’s ‘‘Pocket Tool Guide’® is a little book that will help you select your pliers. Drop us acard forit. It’s free. 3220 Belmont Avenue | Chicago, Illinois @) Mathias BLY FS Bie & Sons

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Madein 2”, oe ae fe and 6 id Blades — P| e— oe way) ks a) Millers Falls e Actual io || = ratchet screw driver No. 55 “Just the thing” for Radio Work! ERE’S a screw driver you'll like at once. Just right for quick, accurate work on small screws. The knurled washer can be used to turn the blade with thumb and finger as you start the screw. A delicate op- eration, but No. 55 is especially designed for it. :

When the screw is started, you can use No. 55 witha right or left ratchet move- ment—or lock the ratchet and you have a plain screw driver. Choice of blades 2 to 6 inches. Make the No. 55 the “‘fam- ily screw driver’’ fora hun- dredusesaroundthe house. Excellent for electricians. A complete line of ratchet screw drivers carry the Millers Falls name—for instance No. 63, designed for all around use, with blades two to eight inches long. Or No. 59, very strong and durable for heavy duty work. Ask to see these at your hardware dealer’s. He’ll show you our new spiral ratchet screw driver No. 61. It’s a beauty. WV he nyou uy your next screw driver, pay a little more and get a ratchet screw driver with the Millers Falls trademark. There’s a world of difference. MILLERS FALLS COMPANY Millers Falls, Mass. 28 Warren St. 9 So. Clinton St. New York icago MILLERS FALLS Satis a

HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY

The Home

Shipshape Siege >

— =

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“How I Keep My Home Shipshape” Three Prize-Winners in POPULAR SCIENCE MONTHLY’S Recent Interesting Competition Offer Many Practical Ideas By Ruth Darling Shultis Albion, Michigan First Prize, $25 Webster, ‘“‘ship- CCORDING to shape” means neat or orderly. According to modern housewives, ‘“‘order’’ means adequate places for putting things away. In the half-dozen homes we have owned, there was originally a general lack of cupboard room, perhaps one small cupboard in the kitchen or elsewhere appar- ently having satisfied the builder’sidea of necessity. We have gone from one home to another, through the years, veri- tably building in cup- boards! So we feel that we always left a house more “shipshape” than we found it! Our home here in Albion had one kitchen cupboard, built in the wrong place. To date, we have built in this house two big draw- ers (in waste space under a stair landing), and seven cupboards of vari- ous design and size, each for a definite use and in the most convenient lo- cation. These cupboards in the walls not only afford con- venience in storing 9 cupboards, actually built them “‘in,” as the two beside the mirror, for toilet articles, whose doors close flush with the wall, are 4 in. deep and completely utilize the wall depth. They are built of hard pine and beaver- board, like the others, with doors opening away from the mirror and s0 constructed that mirrors may be set on the inner sides. The third bath- room cupboard is deeper, being set, like the others, 4 in. in the wall, but p: ojecting 6 in.; it is 35 in. high, 20 in. wide, with four 9-in. shelves for towels and bathroom supplies. This cupboard is set in the space above the toilet box, and a glimpse of it is shown by a reflection in the mirror shown in the lower illustration. We are never deterred from placing cupboards where we wish them because of the doors’ swinging in the

articles, but con- tribute to the neat- ness of the home. In the kitchen we built one deep dish-cupboard into the unused head- room over the cel- way. We plan the doors as carefully as the cupboards themselves, for an awkward swinging door often spoils the convenience of the cupboard. The

and double medicine boards are the sink and drainboards, beneath which are two more cupboards for kitchen utensils. The backs and door panels of these cupboards are made of beaver board, the rest of the material used being heavy enough to be very substantial. The finish is white enamel or stain, to correspond with the room finish. In the bathroom we have built in three cabinets in lar stairs. Oppo- accompanying il- site to this we lustrations show built another, run- not only the cup- ning from floor to boards, but our | ceiling. Between method of folding Kitch ith : a these two cup- itchen cupboards with doors open and closed, the doors by hing- bathroom 2 ing one onto an- other and swinging them back against a small wall space,

Honorable Mention Harry C. Mosher, Dowagiac, Mich. J.S. Hagen, Des Moines, Ia. C. P. Andrew, Charlotte, N. C. S. A. Fraser, Middletown, Ohio.

—- nm —$

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9 “in,” vas yr toilet with the ly utilize ll depth. are built rd pine

beaver- like the with opening from the and so ructed mirrors ye set on ner sides. ‘ird bath- cupboard er, being like the , 4 in. in . ojecting . high, 20 four 9-in. wels and lies. This t in the he toilet apse of it reflection shown in ration. * deterred ‘upboards sh them 1e doors’ in the > plan the carefully ‘upboards es, for an swinging en spoils 2nience of yard. The nying il- is show the cup- but our of folding by hing- onto an- k against

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HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY

—— ‘How I Keep My Home Shipshape”’ By Alice G. Whitman Canso, Nova Scotia Second Prize, $15 HEN Edward and I were married, we came to live in a small fishing- town on the seacoast, in the old home- stead in which his father and grandfather had lived before him. It was a house of many possibilities—a low, rambling place, with a door in the center and rooms on each side, and an open fireplace in every room. When we came into possession of the house, it was painted a dingy brown with darker and dingier brown trimmings. Inside the woodwork was of the same dingy hue. First of all, we had the house reshingled and the shingles stained with a creosote stain, all the trimmings painted white, and the roof a moss green. We then turned our attention to the inside, and white paint worked wonders.

Old cupboards con- verted into’ china closet and bookcase

We painted allthe woodwork white, leaving, of course, the old mahogany balustrade and stair treads. Needless to say, the old wallpapers were unattractive and the house had to be repapered. In the dining-room we put a blue tapestry paper; in the drawing-room a plain yellow oat- meal paper. and in the library a soft gray. The kitchen walls, above the wainscoting, we covered with a plain yellow table oil- cloth. It is a durable wall-covering, easily cleaned with soap and water. Before we papered and furnished the rooms, we turned our attention to some of the 27 pantries or closets the house contained. We are delighted with the transforma- tion of a cupboard in the dining-room— the one beside the fireplace. We had the door removed, extra shelves put in, then a leaded-glass door and a drawer and closet provided underneath. This closet is one of the most convenient things in the saving of time and labor. Here I keep my best china; in the drawer, tablecloths, napkins, and doilies. In the cupboard below we have hard wood for the grate. In the drawing-room two pantries were transformed—one into a bookcase for choice books, the other into a window- seat.

Shelves are of pine stained walnut.

In the library we had low bookcases | made to go all around the room. These

111

More Than §0,000 Now In Use

Makes Your Car or Truck Two-In-One Power—The Ruckstell Axle is revolution- Guin the performance of light cars and trucks. It has solved the great auto- motive engineering problem—com- ate Two Direct Opposites In Ses: and SPEED. Simply move the lever and you go through the muddiest roads; climb stubborn hills on high gear; negotiate congested traffic. For trucks it insures “setting there” and back quicker, with practi-

a S- Move the lever again. and you havea speedy car or truck for city driving or de- livery or level country highway driving. Thou- sands of farmers and busi-

ness concerns everywhere cally double load ca- say the Ruckstell Axle saves pacity. Increases half time in getting to town power 55%. and back home. Noiseless in oper- ation. No cutting, no brazing, no weld- ing—doesn’t change principle of car or truck construction. ¢ Take it to Clip the Coupon—,,,.... nearest SE dealer for FREE DEMONSTRATION, or mail direct to our Kansas City office gq Tec ceesaasacccaseasses Seaeaaacaads

i e * for Free Booklet, Prices, etc. Ruckstell ._ This coupon is good for Free Demonstra- » performance will surprise you. # tion of the Ruckstell Axle at nearest Dealer ¢ Ruckstell Sales & Mfg. Co. ¢ or for Free Booklet giving full particulars. J e + Desk 19A Kansas City, Mo. , a (194) ° Berkeley,Cal.;LosAngeles,Denver,Butlalo, 2) “V272C+++-++++--++-+22e0seeeereeeeeeeeeeecterseeeeeereeseenees : In Canada: Ruckstell Axle Co.,Ltd., : Toronto and Montreal. Address Cee ccc e cree cccce reece rece eee ee eeeses sessssesesseseee® ° e . . _ Moke CO COREE COU oe siididiccaccicdiécdesiceccceaaseede + SSSeteeseeetessteeeeeeasesesae Sencccenccanacescesoceoeeeseeee ieee cae on ae | The Gregg FootballGame 100 ENVELOPES -ntific ime dev ym corre ill Printed With Your Name and Address a cienti Ag 192 ¢ aL ral hihinents Clear, white bond paper, with envelopes to match. ee ha ee ee sbepdepe ao Baca oes Hl ie ~ sa you po staid, for only $1.00. (West of Denver and y oa a xine ag ote Daes ows os outside of U: S. $1.10.) If inconvenient to send the phe Late garg peated, over 50) money, we will ship C. O. D. Write name and : rdd Ir ie hinks best, At your : ealer fee APEC 308 82 " Di iinly. Money returned if you are not more th | Write for illustrated ) folder satisfied. Order toda ELITE STATIONERY CO., 5085 Main St., Smetioat P Pa. Sellsfor$1.25. Agent’s Sample 65c.! EW CAP PEN RETAINER FITS INTO BARREL aasOLUTELY FRICTION-TIGHT PREVENTING TWISTING OF TUB NON-LEAKABLE : ==s nomen —— —_ ITS THE POINT. HAS EIGHT GROOVES FOR INK TO FEED Imported from Japan. ‘It makes Carbon Copies.”” Guaranteed forl year. Hustlers Making $20 Daily? Money refunded if you don't think it's the best = n you ever wrote with. Up to 150 per cent Profit. Send for _ | ALBERT A. GREGG CO., Dept. S, West Jefferson, Ohio New Self-Filling Bamboo Fountain Pen with Stylo Point

quantity price list and distributing plans. F. SPORS & CO., 199 S. 4th St., Lesueur Center, Minnesota

ng et me

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112 —An Amazing Value in Long-Distance Radio Sets HE popularity of MIRACO radio sets is reflected in our tremendous volume and the hundreds of unsolicited testi- monials that come to us day after day from our thousands of satished users. The MIRACO is so popular be- cause it is priced at a ridiculously low figure for a real quality set. Just think, only $29.50 for the model shown in the illustration above and users tell us that they have gotten as many as 122 stations in three con- secutive nights and many of them over 2000 miles away. For instance, Mr. E. D. Elliott of Milford, New York, got London, England, Fair- banks, Alaska, La Palma, Panama, San Francisco, Los Angeles, Hood River, Oregon and many others with- in several evenings. Others have done equally as well. Everyone can now own a Quality Radio Set These two improved MIRACO models make it possible for every family to own a set—to have a box seat for the opera or symphony or jazz concert right in their own living room. Workmanship is unexcelled-—easy and simple to operate—always de- pendable. Solid mahogany cabinet— fully guaranteed against any defects in workmanship. *29.50 PRICE FOR 2-TUBE SET 4-TUBE SET *54,50 Write for our new bulletin today. DEALERS—AGENTS There’s still some territory open. Write or wire for proposition. Midwest Radio Company 808 Main St. Cincinnati, Ohio ‘“‘How I Keep My Home Shipshape”’ By Gladys B. Van Voris, Cobleskill, N. Y. Third Prize, $16 ys ALIZE a mid-Victorian house, neither Colonial nor modern; its beauty depending entirely on its cleanli- ness, orderliness, and state of repair. The last—state of repair—is our problem, so we have tackled it ourselves with the | help of one paperhanger. When our house needs papering, we select a cheap paper, but are careful about | color and design in order to use it without eyestrain and headache until actually soiled. It is soft tan or gray for living- room, plain or practically so; light gray or softly flowered designs for the bedrooms. Not caring to hang our pictures from molding, we finish our walls with 34-in. quarter round—very inexpensive and giv- Two views of the at tractive interior of Mrs Van Voris’s home ing an artistic finish when painted to match woodwork. I find old ivory flat paint excellent for woodwork and white enamel for kitchen and bathroom. I always keep glass jars of both paints and small paint brushes ready to touch up any spots where the paint has been knocked off. This treat- ment of woodwork has lasted 10 years without repainting—just washing with good soap and water and occasionally touching up. Floor treatment is most important, and ours is so highly successful, many have asked us our method. Large boards and cracks needed crack filler first. applied old-fashioned yellow floor paint. After two days of drying, we spread on smoothly a coat of light oak varnish. I wish you could see our lovely mellow floors! Because we used good varnish, we have only renewed once, save on stairs, in bathroom, and on the kitchen linoleum, which we do about twice a year. We | varnish every other tread of the stairs so as to have some to use, and do the kitchen and bathroom by halves. Varnish and paint applied at the first sign of wear, homemade washers for faucets, our frequent porch painting and waxing, and our loving care of our handi- work, together with the use of mild soaps for our surface cleanings, are the most im- portant means in keeping our home ship- shape and reducing our repair bill to its minimum. Then we | HOME WORKSHOP -DDEPARTMENT OF POPULAR SCIENCE MONTHLY COMMERCIAL Meyer Both Company, the largest Commercial Art Organization in the Orld offers you an unusual opportunity for practical training, based upon twenty-three years of success. This nationally known organization each year produces and sells to advertisers over 15,000 commercial drawings. Meyer Both in- struction is the difference between successful fact and experimental theory This well paid profession equally open to men and women. Home study instruction. Get Facts Before You Enroll in Any School Ask the Advertising Manager of the leading news- papers in your city, anywhere in the United States, Canada, England or Australia about the Meyer Both Company—let them tell youabout us. Write for our illustrated book telling about the success of our students—for one-half the cost of mailing—four cents in stamps. MEYER BOTH COMPANY Department of Art Instruction Michigan Ave. at 20th St., Dept. 35, CHICAGO, iLL. Note—To Art and Engraving Firms: Secure practi- cal artists among our graduates. Write us. LEARN BY DOING Every phase of all ranches 8 ELECTRICITY taught by Actual Practice In America’s foremost and oldest institution for trade training No Books Used Individual Instruction Start Any Day Write for FREE 64-page catalog THE NEW YORK ELECTRICAL SCHOOL 40 West 17th St., New York City : you can make $15 to $60 weekly in your spare time writing show cards. No canvassing or soliciting. We instruct you by our new simple Directograph System, supply you with work and pay you cash each week. Write today for full particulars and free booklet. ‘ WEST-ANGUS SHOW CARD SERVICE LIMITED Authorized Capital $1,250,000.00 63 Colborne Building, Toronto, Can. Your Skin Can Be Quickly Cleared of Pimples, Blackheads, Acne Eruptions on the face or body, Barbers Itch, Eczema, Enlarged Pores and Oily or Shiny Skin. FREE Write today for my FREE BOOKLET, “‘A CLEAR-TONE SKIN,” telling how $1000 Cash says ! can clear your skin of the above biemishes. cured myself after being afflicted 15 years. __| E.S.GIVENS, 153 Chemical Bidg., Kansas City, Mo. | ee ST

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ice and trade ed ion atalog K OL City — }on ma, cin. LET ow ears. shes. TT Sr.) oe HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY Attractive Living-Room Bench Is also a Drafting-Table HE problem of where to put a draft- ing-table and drawing-board is one that puzzles most home workers. I solved it by building the combination drawing-table and seat for the living-room illustrated below. Under the hinged seat is a box where paper, architectural books, rolls of plans, CHAIR Back. [) drawing instruments, and the like can be asa prawinc- BOARD.,, The combination bench and table in its dual r6éle, and diagram showing construction kept. The back of the seat is hinged to the arms, and when tipped forward serves as a drawing-board. Small brass hooks hold it in either position. The ends of the seat are 1 or 11¢ in. thick, and the end battens of the draw- ing-board are 1 by 13,4 in., rabbeted and fastened to the board with screws in such a way as to allow for any shrink- age. The remainder of the stock is 34 in. thick.—A. L. Dorr, S. Pasadena, Calif. Extension Ladder for Roof Work Has Safety Fastenings HEN a ladder for roof work is to be extended over its usual length of about 14 ft., I fasten the extension to it with ordinary hasps and staples, as illus- trated. Harness snaphooks are used to prevent the hasps accidentally — be- coming undone. The ridge hook is homemade and bolted securely to the upper end of the extension, @ which is a light, solid eypress or pine board. The steps or foothold pieces are in two thicknesses, held with nails driven through and solidly clinched. I have used this device hundreds of times and find it perfectly satisfactory. It avoids the risk of accident with the makeshift nailed extensions so often used, and also saves having to carry several sizes of ladders in my _ storeroom. — CHARLES W. HUBERTZ, Corry, Pa. Extension is held by hasps and _ staples Substitutes good, Science has found a delightfully new way to quickly remove fat and obtain a normal waistline— without straining your heart with violent gym- nastics or weakening your system by starving. Formerly those who wished to reduce without dieting or strenuous exercise had to go to a profes- sional masseur. His method effectively dislodged the fat and brought about the desired reduction. But it was expensive and time-consuming, and so few could take advantage of it. Remarkable New Invention But now a wonderful new invention brings this same effective method within the reach of all. The Weil Scientific Reducing Belt uses this same massage principle, acting by means of its specially prepared and scientifically fitted rubber. It is so constructed that as you wear it, every breath you take and every movement you make imparts a constant gentle massage to every inch of the abdomen. Working for you this way every second, day and night, it reduces much more rapidly than ordinary Massage, saving both time and money. Actually Removes Fat It does not merely draw in your waist and make you appear thinner. It actually takes off the fat. Within a few weeks you find 4 to 6 inches gone from your waist- line. At the same time all your stomach disorders, constipation, backaches and shortness of breath dis- appear as the sagging internal organs are put back in normal place. Man or woman, you are filled with a wonderful new energy, and both look and feel 10 to 15 years younger. The Weil Belt is used by hundreds of professional athletes and jockeys because it not only reduces quickly but at the same time preserves their strength. Highly endorsed for its healthful principles by physicians everywhere. Satisfaction guaranteed or your money back without question. Write today for full description. If you write at once you can also get in on a Special Reduced Price Offer being made for a limited time. Mail coupon today to THE WEIL COMPANY, 106 Hill Street, New Haven, Conn. Produces same result as an expert masseur, but far quicker, easier and less expensive. solid, normal tissue for that bulky, useless disfiguring fat, yet does it so gently that you hardly know it is there. 113 New Self-Massaging Belt Reduces Waist—£asily! As shown above, every move of your body walk- ing, climbing stairs — merely breathing as you sit—causes the Weil Belt to massage your abdo- men. It is working for you every second, The Weil Company, 106 Hill Street, New Haven, Conn, | Gentlemen: Please send me, without obligation, complete description of the Weil Scientitic Reduc- ing Belt and also your Special to-day Reduced Price Offer. | Ne tik paca damn we cece waa | Address | City Stat PRINTING @ You can earn $15 to $50 a week writing show fm cards in your own home.—No canvassing.—A : on profitable profession easily and quickly earnt by ournew simple graphic block system. Artistic ability not necessary.—We teach you how, and supply you with work—Distance no object. Full particulars and booklet free. WILSON METHODS LIMITED—DEPT. C 64 East Richmond, Toronto, Canada. $25.00 in Prizes See top of page 8 in front of book for full details offers Big PROFITS Printers’ wages are now so high you can : make big money in spare time ith oneof our printing outtits. No experience necessary, Our instruction book makes every- thing easy. Presses $12 up. Pay for themselves in a short time, Write today for catalog pres: es, type, ink, paper, cards etc. THE PRESS CO. X;} Meriden, Conn, 4 3 Ei fe): Automobile Necessities 1. A positive HEADLIGHT TELLTALE selling at $1.25. 2. A GAS GUN selling at $2.50 which enables the driver out of gas to borrow enough from the next passing car to get home, Send for Circu- lars. Agents Wanted. THE HANDY DENTAL SPECIALTY CO. SOMERVILLE, MASS. LEARN CARTOONING Successful cartoonists earn big salaries. now earn $75 to $200 or more a week. in creating ORIGINAL heads, figures, animals, etc. | | popular cartoonists of to-day learned to draw in their spare of Cartooning and time, at home, through the Landon Course The Landon Picture Chart Method of teaching ORIGINAL drawing makes car- tooning easy to learn. Hundreds of sketches like the above explain every step ond 6c. in stamps today for sample Landon Picture Chart and full expla- nation of this wonderful course, also tong list of successful Landon students and information showing possibilities for you. Please state your age. The Landon School, 751 National Bidg., Cleveland, Ohio Many of the most : Four Successful Landon’ Students From One Village Here is the record of four boys~——all from Nap- panee, Ind., (2200 popu- lation) who, after taking the Landon Course, won national reputations. Merrill Blosser is now nationally famous as creator of ‘‘Freckles and his Friends.”’ Henry Maust’s work appears in Saturday Eve- ning Post, Cosmopoli- tan, etc. Francis Parks, follow- ing their advice, is now a cartoonist for the Omaha News. Fred Neher is comic artist with the Universal Feature Co.

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114 HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY 06 0606 06 O46 06 06 06 06 06 26 O80 06 06 06 06 06 06 06 OCDE OE 06 06 0006 06000000 0000060006000" in manny of ‘Tone Federal Radio Parts When only Federal Radio Parts are used in your receiving set, the beauty of tone and clear speech reception is exceptional. Behind each of 130 Federal Radio Parts are exacting standards and traditions of over a quarter-cen- tury’s leadership in the field of tone reproduction. a PO at a ah a ah Meo gh 7. a XIX rl Insist on Federal Parts when purchasing. o Rooke eho ete he oLoete oakoate dt re 6 9, A book,“The Radio Work Bench” aids the novice in avoiding pitfalls. Sold by Federal Dealers—25c. In Canada, 35c. # 0° ee se lS Pe 9 of “a ia? ee 50 i” a? ah ge 9 sy "e' ooops es es a °% ° ou ae of Sock 4, Po task Po Mo a%e cheats Moatectec®, Poe oe eG eSe- ele afe-afe ae alo ale ee alo-ale ole fe ote of 1 So oho he oe oe ae eSece ale ae ate ate efecto che ote ote ele eteate You can buy all the materials for a complete home direct from the manufacturer and save four profits on the lumber, mill-work, Price includes all lumber cut to fit; highest grade interior wood work, siding, flooring, windows, doors, glass, paints, hardware, nails, lath, roofing, with complete instructions and drawings. Freight paid to your station. Permanent Homes—NOT PORTABLE. Many styles to choose from. Write aperest mill today for FREE Money- me Saving Aladdin and No. 106 ing room, dining room, oe thang kitchen, bath. 4 other plans, some with pan- tries, dining alcoves, grade inside cellar entrances, free Ca heh, Ate nb ytrene fig ose] Laree living room, kitchen, 3 bedrooms, large veranda— an ideal place for outdoor dining- -room or sleeping ——. ) buiid ie ae p Rati one bc Summer cottage price includes lumber cut-to-fit — tions explain every step. Five nail in place, windows, doors, hardware, nails, roofi plans shown in Aladdin catalog. _—. etc. Freight paid to your Station. Write today for — ummer Cottage Booklet No. 1095. The ALADDIN CO., BAY CITY, MICHIGAN Wilmington, North Carolina; Portland, Ore.; Toronto, Ont. Chemistry . Simple Formulas that Will Save Time and Money “ SS OUR tools and steel instruments are very susceptible to atmospheric mois- ture. They rust easily if they are not in constant use. Smaller instruments can be cleaned readily from rust by placing them in a saturated solution of tin chlorid over- night; the reduction that takes place removes the rust. After taking up the instrument, you should wash it with water and place it in a hot solution of soap and | Home Workshop water, to which alittle sodium carbonate | has been added. Dry the instru- ment, dip in aleohol (dena- tured) to re- move last trace of moisture, and polish. Rusting is — prevented quite easily if pre- =a cision _instru- a ments, such as micrometers, after being freed from any rust spots, are placed in the following solution: A teaspoon of ker- osene in a glass of benzene, to which a very small piece of paraffin, less than half the size of a pea, is added. When the solution has entered all crevices, remove it and place the instrument to one side so that the benzene may evaporate. Metals such as gold, platinum, and silver are influenced to the least extent by the atmosphere; the lesser noble metals, such as iron, copper, lead and zinc, soon show signs of oxidation by the formation of oxids of these metals. The noble metals can be cleaned by rubbing their surface with soft leather, provided the tarnish is not due to sulphids. The sulphid tarnish of silver, if not too old and too deep, also can be cleaned in this way. If it is severe, use & mild abrasive, such as precipitated chalk. If the precipitated chalk is mixed with a little water and a little ammonia, a chemical action is set up as well as the abrasive action of the chalk, and this will clean the silver thoroughly and quickly. The differ- ence between tarnish and cor- rosion of a metal is in the depth of the oxidation. When it is slight, it is tar- nish;whendeep, it is corrosion. The most com- mon method of cleaning metals from tar- nish is by the use of an abrasive, although chemical methods are sometimes to be preferred. The selection of the proper cleaning method depends upon the chemi- (Continued on page 115) a \ Making an anti- rust solution Removing _ stains from polished brass SN os cme a cc ee ia,

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CO OY WU em Jet ee ee a TT cE SS I HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY 115 Prizes for Photographs i YOU have made or are making any article with the aid of POPULAR SCIENCE MONTHLY 'Sblueprints, don’t fail to make aphotograph of yourhandi- work. Then send usa print. We are always glad to see such photographs, and for each one considered worthy of publication we shall pay $2. Address the Home Workshop Editor, Popular Science Monthly, 225 West 39th Street, New York. Steamtight Kettle Cover O RETAIN the full flavor of meat and vegetables and to prevent odors and steam from escaping, steamtight cov- ers can be made quite easily for the usual convex kettles and cooking utensils. The cover consists of an ordinary cake tin with slightly tapered _ sides, soldered to the regular kettle cover. After this the bottom is cut off, leav- ing only a flex- tapered which Flange is made from a cake tin ible flange, wedges into the kettle and fits closely, especially if a weight such as an old flat- iron is placed on top. The only possible difficulty is to find a cake tin to fit the kettle, but I have found the device prac- tical in my own household and am quite sure that it effects some saving in gas.— E. W. CORNELL, Adrian, Mich. Home Workshop Chemistry (Continued from page 114) eal character of the metal to be cleaned. Brass is a mixture of zine and copper, and the tarnish produced is mainly the dark sulphid or oxid of copper. A quick and economical method of cleaning this metal is to wipe, and at the same time polish, with a mixture made by adding a little acetic acid to water and stirring in a teaspoon of salt. The odor of the solution is like that of vinegar. Wash the cleaned article with water and rub dry with a little precipitated chalk. Copper can be cleaned in the same way, the method giving a bright polish. Oxalic acid in water cleans copper more quickly, but it does not give it so bright a finish. Aluminum should not be cleaned with caustics, as they quickly eat it up. Steel wool is effective, but also quickly wears away the metal. A chemical cleaner that can be used to remove the most stubborn deposit, con- sists of a mixture of nine teaspoons of aluminum sulphate and one of sodium carbonate. The vessel is filled with water —if it is an aluminum pot—and one or two teaspoons of this mixture is added. After the water has been brought to a boil, the vessel will be cleaned. If it is a small aluminum object, a pot is filled with water and the object placed in it after the above salt mixture has been dissolved.—E. BADE. VA Men Needed in Electricity Good salaries and rapid advancement await trained men O PROFESSION offers greater Zz opportunity to-day than Elec- tricity. Salaries of $12 to $30 a day are not uncommon and the opportunity for advancement is unlimited. For this is the Electrical Age. New uses for electricity are being discovered every year. The growth of Radio is simply one illustration of the progress that is yet to be made. As Forrest Crissey said recently in The Saturday Evening Post—“The de- mand for electrical work is increasing immensely and electrical contractors as- sert that the supply of electrical work- ers cannot overtake the demand for several years to come.” INow is the time to prepare for a good position in this profitable, inter- esting profession. Best of all, you can study right at home in spare time through the Inter- national Correspondence Schools—just as so many other men have done. These courses are the most authoritative courses ever offered, and have been en- dorsed by both Thomas A. Edison and Charles P. Steinmetz. the late Dr. f This 3$ —5-32 Ct. acaiione diamomd soll- taire of fiery radiance at $32.65. Also hun- dreds of equaily amazing money - saving At offers in latest Diamond Bargain Bulletin. § «This 75 year, oldest, largest Diamond Bank- ing firm in all the world lends money on diamonds. Thousands of unpaid loans and other bargains. Must sell Ww. Why Pay Full Prices Costs Nothing to See Investigate this offer: Any diamond sent for absolutely Free Examination at our k. No obligation. No cost to you. Loan List Free—Send Now Latest bulletin includes Unpaid Loans—sent ree. Describes Diamond ergaine in de- tail, gives guaranteed cash loan values. Ex- plains « unlimited “ly Seg be privilege at price paid us. Send today for Bargain Bulletin. No Sbligation. Edition Limited—Write Now. § Jos. DeRoy & Sons4721 DeRoy Suing Quly Opposite Post Oftce Pit Pittsburgh, Pa | and recei Just mark and mail the coupon printed below and full information about Electrical Engineering, Electric Lighting, Electric Wiring, Electric Railways, Radio or any other work of your choice will come to you by return mail. To-day—not To-morrow— is the day to make that all-important start toward success. Mail the Coupon To-day — eee eee ee TEAR OUT HERES Re INTERNATLONAL CORRESPONDENCE SCHOOLS Box 7490-C. Scranton, Penna. Explain, without obligating me, how I can qualify for the position, or in the subject, before which I mark X. ELECTRICAL ENGINEER Cj) CHEMICAL ENGINEER Electrician Pharmacy Cj Electric Wiring _} SALESMANSHIP (} Electric Lighting J ADVERTISING MAN L}) Electric Car Running « a meng oy rll ; rm - Meactric Trac Show Card and Sign Paint’¢ Bl nid bear “oars RAILR OADPOSITIONS LJ Electrical Draftsman ILLUSTRAT (_] Electric Machine Designer : Daatchen OR Telegraph Expert ™ BUSINESS MANAGEMEN Practical Telephony P Ss ANAGEMENT CD MECHANICAL ENGINEER 4 et act teed usiness Correspondent () Mechanical Draftsman BOOKKEEPER a a ai Practice Stenographer and Typist C} Gas Saamnens 4 Gere ra Accountant “IWEr OER _ raftic anagement [) CIVIL ENGINEER Co ial L) Surveying and Mapping GOOD ENGLISH 4 pero te STATIONARY ENGINEER ARC EC IVIL Vv 4 Architectural Draftsman HS allras tit Gherk Architects’ Blue Prints 2 Textile Overseer or Supt. |) AGRICULTURE (_) PoultryRaising [) Spanish (J) Automobiles (|) RADIO _) PLUMBING AND HEATING _] Sheet Metal Worker CL) Navigator Name side aac pce ee a Present Business Occupation___ pects _.Address— Street ané Non. 2: ee _State— Easy toDraw Cartoons When Shown in the RIGHT WAY Som of tl cleverest cartoonists om learned h te th t b) ! Cartoonist Evane’ ate pa pad to L earn Method and are n MAKING GOOD MONEY your draw ind let Mr. Ey vans see if you have ' Portfolio of Cartoons and [ul about the cot It is not expensive. THE W. L EVANS SCHOOL OF CARTOONING Cleveland, Ohie 825 Leader Building £0 NS TRIE COE

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116 HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY The Race Starts when the Count Starts! Which men or machines win out in the race for produc- tion? Thosethat have records to show what they’ve done —and can do! Production-records (Veeder records) never stand _ still. They give you a basis for betterment. They challenge improvement. At any machine that can be | improved—on any job that can be ‘‘stepped up’’—the gains start when the COUNT starts ona COUNTER Thissmall Rotary Ratchet Counter (No. 6) counts reciprocating movements of the lever, as required for recording the output of innumerable small machines. When the lever is moved through an angle of 40 to 60 degrees, the counter regis- ters one. The further the lever is moved, the higher the number registered. A complete revolution of the lever registers ten. This counter can be adapted to no end of counting purposes, by regu- lating the throw of the lever. Price, $2.00. (Cut nearly full size.) Small . Revolution Counter, also $2. The Hand Tally Seestented below is used for counting anything from number of people attending a ball game, to number of packages in an inventory. In the public place it counts persons; in the factory or store it counts stock; in the “open” it may count anything from cattle on a ranch, to poles on a_ telephone line! Registers one for each pressure of the thumb lever: counts up to 10,000, then repeats. Can be set back to zero from any figure by turning knob once round. Size, exclusive of finger ring, 2 inches greatest diameter. Price, $5.00. Write us about that counting problem of yours—it’s prob- ably answered in the 80- pageVeeder booklet; copy free | The Veeder Mfg.Co., 44 Sargeant St., Hartford, Conn. | Harrow Disk Forms Roof of Novel Bird-House OR birds that nest in a hollow tree, it is possible to make attractive post bird-houses like the one illustrated. Bore a large hole into the post from the top with an expansive bit, or bore several holes with a smaller bit and chisel out the open- ing. Then bore one or more- entrance holes. Make a cover by pouring concrete in a wooden form and fastening an old har- row disk to the top. If the moist concrete is rounded over the edges of the hole in the disk, as indicated, the cover will be quite strong and it will be possible to remove it for examining or cleaning the nest cavity whenever neces- sary.—LOUIS SCHNEIDER, Clinton, Mo. Post bird-house with its remov- able disk cover Automatic Fasteners Hold Garage Doors Open SIMPLE device for holding garage doors open automatically is illus- trated below. Two swivel bolts are made as detailed and fastened through the lintel or head jamb of the door. They are free to turn as the long locking bars pass through the slots in them. When the doors are opened the required distance, DOOR SHUT DOOR OPEN AND LOCKED AND LOCKED Even in a high wind the heavy garage docrs are prevented automatically from closing notches in the bars engage the bolts and act as a catch. The bars then will hold the doors open against the strongest wind. If the garage has a side entrance, the same bars also may be used as a lock. It is necessary merely to cut a second notch in each bar as shown, and enlarge the pivot hole to an oval. Chains or bell cords fastened to the ends of the bars and passed over pulleys provide convenient means for unlocking the doors.—F. N. C. Trimming Drain Tile ig IS quite a task to cut drain tile with a cold chisel, and the danger of having it break at the wrong place is ever present. A better method is to mark around the tile with a chisel where it is to be cut and then to pinch away the tile little by little with the jaws of a monkey wrench, just as glass is trimmed with the notches in a glass cutter.—JOHN L. DOoUGHENY, Toledo, Ohio. A Vital Factor If reliability is important in the larger and more conspicuous apparatus, it is even more so in the small and often concealed parts, where a flaw will nevertheless prevent absolutely the working of the set. That is why Kellogg miniature con- densers are de signed and manufactured with the same painstaking care as the famous variable condensers and other larger parts. Our miniature condensers are all made exactly the same size mechanically, being 17% inches overall, with a tip diameter of 3g inches. Electrically they are built in seven different capacities from 250 micro- microfarads (No. 506) up to .01 micro- farad (501). The plates are of heavy tin foil insulated by specially prepared paper of high dielec- tric strength. This is tightly rolled and the copper terminals soldered to the brass end pieces which are securely crimped to the fiber cover. No. 501 01 Mz. F. No. 504 .0010 M.F. No. 502.005 M. F. No. 505 0005. M. F. No. 503 .0025 M. F. No. 506 .00025 M. I. No. 507 .006 M. F. Use—Is The Test KELLOGG SWITCHBOARD & SUPPLY COMPANY 1066 W. ADAMS STREET CHICAGO, ILL, A Test Every Man Past 40 Should Make Medical authorities agree that 65% of all men past middle age (many much younger) are afflicted with a disorder of the prostate gland. Aches in feet, legs and back, frequent nightly risings, sciatic pains, are some of the signs—and now, a member of the American Association for the Advancement of Science has written a remarkably interesting Free Book that tells of other symptoms and just what they mean. No longer should a man approaching or past the prime of life be content to regard these pains and conditions as inevitable signs of approach- ing age. Already more than 10,000 men have used the amazing method described in this book to re- store their health and vigor—and to restore the prostate gland to its proper functioning. Send immediately for this book. If vou will mail your request to the Electro Thermal Company, 4034 Main Street, Steubenville, Ohio—the concern that is distributing this book for the author—it will be sent to you absolutely free, without obligation. Simply send name and address. But don’t delay for the edition of this book is limited. BLANK CARTRIDGE PISTOL tection against Burglars, Tramps, & Well made and ef- * fective; modelled on latest type of Revolver; appearance alone is enough to scare a burg- lar. When loaded it 2a be as effective as a re revolver without Med to life, Ittakes stand- ard .22 Cal. Blank Cartridges’ obtainable every- ¥ = lb Price SOc. ey quality $1.00 host: bald. Blank “Smith by express,5O0c per 1 in & Co. Dept. 144, Racine, Wis. —

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POPULAR SCIENCE MONTHLY 117 EE Le Kerr n. wey seed 25} S ee wathere t is a § pone ng. that knows how to take from its environment the wherewithal to build the body of the organism it animates. From the little seed you place in the ground this something sends roots into the earth, blades or branches into the air, and takes from the earth and the air that with which it builds. Within the egg this something is wooed to life by the warmth of the brooding mother’s breast. CHIROPRACTIC teaches that this something knows the secret of converting food into flesh and blood, and carries on all the processes of life, in the human body, by means of impulses sent over the nerves. It teaches that when a@ nerve is impaired by a vertebra becoming misaligned, these im- pulses do not flow over the nerves normally, and the result is what we call dis-ease. To get the dis-eased member to function again it is necessary to adjust the vertebra that is pressing on the nerve, to nor- mal alignment, thereby permitting the normal flow of impulses over the nerve. © ppFinitIonN % _ To adjust the vertebra to | "phen a ioe spenetia normal alignment isthe work | anda si stment,wvith the hands, | ° | ofthe able oe of the of a competent chiropractor. | spinal column to normal posi- | tic she the pu so of Z, A trial will convince the most e prison ned impulse. A x WA A skeptical of the correctness 6f qe , ” lo FRO OM ANY these principles. Write for information COMPETENT CHIROPRACTOR regarding Chiropractors or Schools z, 3 to the Universal Chiropractors’ Association Davenport, lowa, U.S.A.

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118 How This Man Won Success As an Electrical Expert General Manager of his company at 28 years of age! His own boss—owns his home—married and happy and yrosperous—that'’s the remarkable success achieved by Nallace H. Rohrschneider, now general Manager, Secre- tary and Treasurer of the Hustisford Light, Power and Manufacturing Company of Hustisford, Wisconsin. Mr. Rohrschneider got his start toward his quick and brilliant success at School of Engineering of Milwaukee. There he received the practical, intensive and specialized training that enabled him to make good in a big way. Why Don’t You Get Into This Big Pay Field? The same kind of training that put Mr. Rohrschneider into the ranks of the highly-paid Electrical Specialists will qualify you for brilliant success in this fascinating field of unlimited opportunities. Come to America’s Greatest Institution of Electrical Education. Learn by actual practice in our big laboratories with their magnificent equipment, including motors, dynamos, switchboards, ignition and lighting systems, etc. Recognized experts give you personal instruction every step of the way. Earn Your Way Through This Great College You can earn money to help defray your expenses while you are learning. Our wonderful co-operative plan brings an Electrical Career within the reach of every ambitious man, Our Free Employment Department secures posi- tions for those students who wish to earn part or all of their expenses. In addition, the Department will help you get a good position in the Electrical industry when your training is completed. Class organizing now. Send for big free catalogue. Mail the coupon now. Check the course that interests you most and we will send you special information. Read about the School that trains men for practical and quick success. See how easy it is for you to get the training that will enable you to step to a splendid position and a handsome income. Mail the coupon right NOW. No cost or obligation. ECKESL of ENGIN EERING ef Milwaukee Dept. X-901, 415 Marshall Street, Milwaukee, Wis. MAIL COUPON NOW — Eee eee eee ee ee Cre CellC SCHOOL OF ENGINEERING OF WILWAUKEE Dept. X-901, 415 Marshall St., Milwaukee, Wis. Please send me without any cost or obligation, full particulars of the electrical course I have checked and your big Free Book telling about your institution and how it will fit me fora big position in the electrical field. Also tell me about your Earn-While-You-Learn plan. (Check courses interested in, and be sure to give your education.) —School of Practical Electricity—6 months or 1 year course. Complete general course, covering entire elec- trical field. —Institute of Electrotechnics Practical electrical training Academic education. —College of Electrical Engineering—3 years’ course. Regular collegiate work granting B. S. Degree. 14 High School units or diploma from our Institute of Electro- technics required for entrance. —Commercial Electrical Engineering—1 year course. Thousands of Trained Men wanted in this new profession. 14 High School units or diploma from our Institute of Electrotechnics required for entrance. —School of Automotive Electricity—3 to 6 months. Covers all systems of starting, lighting, ignition, and storage batteries for automobiles, tractors, air-craft, etc. Intensive practical course. —Armature Winding and Motor Generator Repair Course—3 to 6 months’ course. Brief, but intensely practical, leading to well-paying positions. Electrical Home-Service Training with laboratory facilities, for those who cannot come to Wilwaukee. 12 to 30 months’ course. combined with thorough RE ea RS Oe ee en ee Se ene Street- hte... Age-_-_-- ._--Education Equipment for Auto-Camping (Continued from page 75) window in the back. The compartment thus formed serves as a kitchen and dining compartment when the drawer is ex- tended, or as a dressing- or sitting-room when the drawer is back in place under the bedsprings. An iron tent peg at each corner holds down the drops. In Fig. 5 (below) is a view similar to Fig. 4, except that the side drops are ex- tended to form a windbreak. The canvas used throughout is known as shelter-tent material and is strictly Fig. 5. The kitchen quarters with can- vas spread out to form a windbreak waterproof. The sides of the sleeping | compartment are covered with screen and cheesecloth, making this compartment mosquito- and insect-proof, yet providing good ventilation. A piece of canvas may be rolled down on the inside of these sides in case of extremely stormy weather. The front panels connecting with the sides are on hinges and open in, thus giving access to the front or head of the bed when the bed is to be made up. The drawer is covered partially with a top that slides from end to end. This top is used as a cooking and eating table. The rear of the drawer also is equipped with a 2-gallon emergency water tank, which has a small faucet at the rear. When breaking camp, bedding, canvas, poles and ropes are placed on the mattress. These fill the triangular space formed by closing down the sides. This procedure permits of an orderly arrangement, in the drawer, of the stove, cooking utensils, food, toilet articles and a suitcase for extra clothes. When a mealtime stop is made, it is necessary only to drop the tail- gate, pull out the drawer, attach the legs and prepare the meal without disturbing any material not actually to be used in the preparation of the meal. The diagrams in Fig. 3, page 75, give the more important general dimensions. Corroded Battery Terminals -g paaalalggaatae it is hard or impossible to loosen corroded storage-battery ter- minals. A little heat from a torch or other source, however, will usually loosen them. If a torch is not available and you have some of the wafers used on a five-minute vulcanizer, just put one of these on top of the terminal and light it. As it burns away, it will heat the terminal sufficiently. —CHARLES OLSSON, Fond du Lac, Wis. You can build an icebox that is far superior to the average cheap com- mercial refrigerator and one that will save you from $10 to $25 worth of ice a year by following a remarkably simple plan in next month’s Home Workshop. HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY “I wouldn’t sell my course for ten times what I paid for it, if I couldn’t t another.” lorman Tompsett, Tidiaute, Pa. Also Jiu Jitsu and Wrestling Think of it—over 80 complete lessons in Boxing, Jiu-Jitsu and Wrestling—6 big books printed on fine paper and over 200 photographic illustrations— all for $1.67! You can have it on 10-day trial. Send no money. The greatest secrets of the ring, the best blows and guards used by Jack Dempsey, Benny Leonard, Kid McCoy, Jim Corbett, etc. The fine points of feinting, ducking, clinching, breaking ground, judging dis- tance and timing. Instructions on how to train. And a history of the world’s greatest boxers right up to the minute with such famous fights as the Dempsey- Firpo, Firpo-Willard, Dempsey-Gibbons fights, with ring-side views. This course cuts the time of learning in half, The system is based on the methods used by famous Professor Mike Donovan, former boxing instructor at the New York Athletic Club. So quickly do pupils learn that many outbox bigger and stronger opponents after only a few weeks training. Shadow Boxing: To prepare you for your first test, you are put through three fast rounds of shadow boxing—great exercise for producing speed, wind and confidence. Jiu-Jitsu and Wrestling—how to subdue an armed opponent, how to throw an opponent who grabs you from behind, the Gotch Toe-Hold, the Stecher Scissors Hold, the Head-lock, etc. And to build you up physically, you're given a complete set of muscle-building and breathing exercises. SEND NO MONEY: Simply fill in and mail the coupon. When you have the course in your hands, de- posit $1.67 (plus the actual postage) with the postman. Use the course for 10 days—try it out thoroughly. If for any reason, you are not entirely satisfied, return the course, and get your money back at once. Mail the cou- pon now to The Stillman Association, Dept. 1124-F, 50 East 42nd Street, New York. 10-DAY TRIAL THE STILLMAN ASSOCIATION Dept. 1124-F, 50 East 42nd St., New York Send me on approval the Stillman Course. When I have the course in my hands, I will deposit $1.67 (plus the actual postage) with the postman, with the understanding that if, after 10 days. I wish to return the course, I may do so and my deposit will be instantly refunded. If I keep the course there is nothing further to pay. Name PINE ele ed a lo cl he a Se Fes Oe Canadian and foreign orders must be accompanied by cash ($1.67 U.S. funds) subject to money back guarantee if not entirely satisfactory, NEW VEST POCKET ADDING MACHINE Adds as rapidly and accurately asa $300 machine, yet fits the vest pocket. Mechanically perfect. Easy to operate —nothing to get out of order. Everyone who uses figures should own one. , Counts Up to 999,999,999 Total visible at all times. A pull of the finger clears it. Don’t carry a pocket full of pencil stubs and scra - paper todo your figuring. Carry a Ve-Po-Ad. 4 Send no money. 10 Days Trial Just name and ad- dress and we will send machine postpaid. Pay postman on delivery $2.95. Use it for i, 10 days to prove it does all we claim. If | not perfectly satisfied we will refund your money. Limited supply. Send order today. Reliable Adding Machine Corp. 170L, W.WashingtonSt.,Chicago, Il. = Here’s a money maker. Everybody ee a N 4 wants one. Splendid profit, Write for epecial offer, — es ee

Page 103

'¢ 2) ng ing, lon is— rial, and Kid ing, dis- And p to sey- with half, by xing So and ling. first or eed, > an who the plete the , de- man. ghly. n the cou- t. oe have ; the ding iy do keep 1 by intee rs it. sera o-Ad. ney. id ad- tpaid. it for | your oday. rp Pp. o, 11. Write

HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY

A CELE ET cE a, @ ye

Building a Light Utility Stand with Turned Legs 5 enews for many purposes, the light stand illustrated is graceful and deli- finest commercial furniture. The only machine work necessary is the turning of the legs. (The legs also can be made by hand if, instead of the design indicated, a twisted ‘‘turning”’ is used, as described in | the April PoPpULAR SCIENCE MONTHLY on | page 108.) The top is 3,- in.-thick stock, preferably ma- hogany, walnut, or red gum. The rails between the top and the feet are cut from 1!¢- in. stock; the lower stretchers are °,- in. pieces mortised and tenoned into the legs. The legs are dressed down

eate enough to be placed alongside the | §

The completed stand and details showing shape and dimensions of the various parts from 11¢-in. stock to 1 in. square, 22 in. long over all and then turned as indicated with the aid of a sheet-metal templet. The assembly may be made with a good grade of liquid glue and with wood screws carefully countersunk, the holes the glue is thoroughly hard, the piece can be cleaned up, stained, filled, and either shellacked, shellacked and waxed, or var- nished, as the builder prefers. —WILLIAM J. EDMONDS, JR., Whitehall, N. Y.

TO PREVENT oil leaking at the hubs of an auto, an expert mechanic recommends removing the washers and covering them with what he calls a hard grease—a grease that does not melt easily and through which the oil cannot seep. It does not increase friction or wear.—N. G. NEAR.

being filled with wooden dowels. After |

TRADE MARKS COPYRIGHTS PROTECT YOUR IDEAS ANY NEW article, machine, design or improvement thereof, or any new combination of parts or improvements in any known article which increases its efficiency or usefulness, may be patented, if it involves invention, If You Have Any New Ideas which you feel are useful, practical and novel, take prompt action to protect your rights. If you have invented any new machine, or new combination of parts, or improvement, or any new design or process, SEND DRAWING, MODEL OR DESCRIPTION of it for information as to procedure to secure protection, Write Today for Blank Form “Record of Invention” USE THE COUPON attached, and immediately upon its receipt I shall send you this form to be returned to me with drawing, description or model of your idea; promptly upon receiving your idea I shall write you fully as to procedure and costs.

DRAFTING and SPECIFICATION ROOM of CLARENCE A. O'BRIEN, Registered Patent Attorney, Washington, D. C. No Charge for Above Information All communications are held in strict confidence. My personal, careful and thorough attention is given to each case. I offer you efficient, reliable and prompt service—based upon practical experience. Highest references. WRITE TODAY for tree book *‘How to Obtain a Patent.’’ This book will give you valuable information, and it may save you much time and effort. Send for it NOW. My practice is devoted exclusively to United States and Foreign Patents and Trade Marks. Write me freely, frankly and with full confidence; it is very probable that I can help you. Write TODAY. CLAREN CEAO BRIEN REGISTERED PATENT ATTORNEY MEMBER OF THE BAR OF SUPREME COURT OF UNITED STATES, COURT OF APPEALS DISTRICT OF COLUMBIA SUPREME COURT DISTRICT OF COLUMBIA, UNITED STATES COURT OF CLAIMS Practice Confined to Patents and Trade Marks 3 883 3 Security Savings _& & Lom'l Bank Bldg., directly across street from U. S. Patent Office, Washington, D. C. C. aes A. O’BRIEN, Registered Patent Attorney, Washington, D>. <. 883 Security Savings and Com'l Bank Bidg., directly across street from U. S. Patent Office. Please send me your free booklet ‘‘How to ieee a Patent’”’ and blank form ‘*Record of Invention”? with: any obligation on my part. lenpertant— Write er POP EMPOE Soin oss ale giglainie.O ce 20 ORGS SONS CERO NOES CHESS CESaES print clearly PO OS OTC TS oT a Tre

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120 MECHANICS’ HANDBOOK ICS MECHANICS HANDBOOK

330 PACES More than 300,000 sold | ewan book of its Only kind ever written. Pre- pared by experts under the direction of the Interna- tional Correspondence Schools. Written in lan- guage that you can under- stand. Note this partial list of subjects: Weights and Measures; Easily Under- stood Mathematics; Formulae; Mensura- tion; Belting; Hydro-mechanics; Strength of Materials; Boiler Design; Care and In- spection of Boilers; Horsepower of Boil- ers; Chimneys; Exhaust Heating; Machine Design; Horsepower of Engines; Boilers and Pumps; The Slide Valve; Belt Pul- leys; Rope Belting; Cylinders and Steam Chests; Electricity; Currents; Wiring; Dynamos and Meters; Batteries; Cable Testing; Compass Surveying; Curves; Leveling; Etc. Just mail this advertisement with a dollar bill and your name and address, and this 330-page I. C. S. Mechanics’ Handbook or any of the other I. C. S. Handbooks that you = will come to you by return mail. INTERNATIONAL CORRESPONDENCE SCHOOLS Box 7694-C,° Scranton, Penna. I enclose $ for which send me, the Handbooks marked X, postpaid, at $1.00 each. It is understood that if I am not entirely satisfied I may return any or all of them within five days | l | and get my money back. | | (1) MECHANICS’ HANDBOOK (Automobile Handbook (jElectrical Handbook OSalesman’s Handbook Chemistry Handbook L)Advertising Handbook Building Trades HandbookLiBookkeeper’s Handbook OORadio Handbook a a eee Address... |

=>. ALL INSTRUMENTS AT r maxes BAN V3{o/2DRICE! d_ imported instruments for band, orchestra_or ny dimes at astonishingly low prices. Hundreds of bargains in new list. New Guar- tee. 5 Days Free Trial and money back guaranteed.

All famous American

CONN Buescher, Boston, Silver plated ‘old bell Cornet, in case, pearl ae + ehtty used, completes y Ae It, guaranteed new con- one ‘perfect. SI 7.95 list. Our price. =a SPECIAL! Brand new Brass Cornet made by most famous factory in U.S. w pitch, pearl keys. List $35. oces 12. nie known for quarters. Send tor Peace bargain list eoday? 403, 320 S. Wabash Ave., Chicaz Buescher andall other famous makes in re- built, new condition Saxophones — | @ith case, reeds, str i keys, poeierie uilt and replated—get our bargain list for descriptions prices as low as $69.75

waste ti years as at hy Dixie Music House,

HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY

A Waterproof Bag Protects Sportsman’s Camera LTHOUGH the camera is considered an essential on all out-of-door trips, it is apt to be a nuisance, especially when there is any. strenuous action. For that reason the camera case illustrated was devised. It is made of a double thickness of heavy canvas with edges bound with thin leather. Two leather straps are sewed on

the back so that the belt may be slipped

After being wrapped in a waterproof sack, the camera is placed in a bag on the belt through them. A regular camera case snap-lock fastens the flap. stead of grind- @ ing it horizon- tally on top, = ” grind it at a e cutting en slight angle as ene Sees shown. Make the angle be- low the cutting edge the same as that of other tools that are found to work well. As this tool is intended only for light cuts, it may be hardened right out and left that way, or the temper only very slightly drawn. It will then remain sharp and clean-cutting for a long time. The main thing about a tool of this kind is to give the edge a very smooth finish. No tool will cut smoothly if the working edge is ragged.

Write Today For Descriptive Folder of the | New Howard 5-Tube Neutrodyne This remarkable set has created a sen- sation among Radio enthusiasts. Beautiful Black Walnut Cabinet with

special Howard Neutroformers Tube Sockets and Rheostats. = Inde, Licensed by D ° dene UTR ODYN es & & zs z g UTRODYN t = ga Other Patents Pending soos Howard Manufacturing Co. 4240 No. Western Ave. Chicago, Ill. Stop Using a Truss STUART'S PLAPAO- PADS are different from the truss, being mechanico- oa apememers magred self-adhesive purposely to hold the distended muscles securely in place. No straps, buckles or spring attached —cannot slip, so cannot chafe or press against the pubic bone. Thousands have successfully treated them-

Reduced selves at home without Reduced Fac-Simile hindrance from work—most Fac-Simile Gold Medal obstinate cases conquered. Grand Prix Soft as velvet—easy to apply—inexpensive. Awarded Gold Medal and Grand Prix. Process of recovery is natural, so afterwards no further use for trusses. We prove it by sending Trial of Plapao paenkausty FREE Write name on Coupon and send TODA Plapao Co., 790 Stuart Bldg., St. el Mo. MEE RD YG fa sve uo eG is as oe os wa iw o's sw pS 96 6:05:50 -4 9 9 Return mail will bring Free Trial Plapao.

21 Jewels AN Plething lose than 21 Rub: a a fe good enough for sen Sepeh as Tom jewels ty and Style ys Adjusted to the second—temperature— eareic positions. 25 year Gol: Oa je eos =. $1 down. payments. yn

How to Make More Money Unusually attractive profits ea- sily and quickly made at home in spare time, raising guinea pigs, squabs, etc. Thousands being used. Highest price paid to raisers. Market guaranteed. No experience necessary. Write today for illustrated booklet—free. Mutual Food Products Co., Dept. D, 1400 Broadway, New Yor’

ee A EC ee em — ee a

Page 105

ea- ein igs, ing ed. ted ‘ork — ee ee - - ty ng yn HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY Two Mirrors Provide Original Design for Craft Work ao workers who are really good craftsmen often are puzzled when it comes to making a design for orna- menting some piece of wood or metal work. They do not like to copy a stock design and yet good original ideas are hard to develop. Individual and inter- esting stencils, inlays, marquetry, and stained or painted decorations and orna- mental iron- work rarely are seen in amateur craft work. This question of originating designs can be solved quite The two mirrors and the blackened match sticks used for straight-line designs easily by using a designing machine based on the principle of the kaleidoscope. The device consists of two mirrors hinged to a common support. By placing the mirrors upon any regular or irregular design or back of several small objects regularly or irregularly arranged, a sym- metrical design or ornament will be seen at the base where the two mirrors meet. The orna- ment can be changed simply by turning the mirrors, that is by opening or closing them. A triangular de- f 7 Insect design sign is obtained by opening the mirrors to a wide angle. Placing the mirrors at right angles to each other provides four-sided or- naments. Closing the mirrors slightly more forms five-sided ornaments, while six-, seven-, and eight-sided designs are produced by closing them. As soon as the desired design is formed, the mirrors are left standing, and the design is copied on paper. The beauty of this method of designing lies in the fact that the ornament formed. will remain before one as long as necessary.—E. B. A useful ornament composed of leaves HOW to make a trick water swing will be told next month by Dale R. Van Horn. 121 ome) NO CHARGE FOR ATENTS Comitienns OUR OFFER: rxamnaronanp HAVE YOU AN IDEA? YOUR FIRST STEP before disclosing an invention. The inventor should write for our blank form— ‘““Record of Invention’”’ This should be signed and witnessed and returned to us together with model or sketch and description of the invention for examination and instructions. No charge for the above information. Our Three Books Mailed Free to Inventors Our Iilustrated Guide BOOK 1—How to Obtain a Patent Contains full instructions regarding U. S. Patents. Our Methods, Terms, and 100 Mechanical Movements illus- trated and described, Articles on Assignment or SALE OF PATENTS, Patent Practice and Procedure, and Law Points for inventors. 2—Our Trade Mark Book Shows the value and necessity of Trade- Mark Protection and gives information regarding Trade-Marks and unfair com- pelition in trade. 3—Our Foreign Book We have Direct Agencies in all Foreign Countries. We secure Foreign Patents in shortest time and lowest cost. — waist sa eiaeeeti ala neat an apni onieremnaieialll Our Main Office, in the Victor Building (Opposite U.S. Patent Office), Washington, D.C. WE REGARD A SATISFIED CLIENT As our best advertisement, and will furnish to anyone, upon request, lists of clients in any state for whom we have secured patents. Highest References—Prompt Attention—Reasonable Terms New York Offices Philadelphia Offices Pittsburgh Offices 1007 Woolworth Bldg. 714-715 Liberty Bldg. 514 Empire Bldg. WRITE TODAY: Chicago Offices, 1114 Tacoma Bldg. San Francisco Offices, Hobart Bldg. VICTOR J. EVANS & CO. Coupon |:": | . Main Offices: 760 Ninth Street, Washington, D.C. Patent Attorneys Gentlemen: Please send me FREE OF CHARGE your books as described above. Name Address

Page 106

122 | Your Choice = 75c a Week : We have cut the price one-half

No matter what your occupation, one of the home study sets listed below will quickly fit you for a better job and bigger pay. Any set you * select will be sent for seven days’ examination, and if you decide to buy you may pay the rock bottom price at the rate of only 75c a week. But you must act now! The rising cost of paper and binding materials won’t permit us to continue the present low prices much longer. These books are the work of recognized author- ities. They are written in plain, easily understood language, by recognized authorities, and contain hundreds of photographs, diagrams, tables, etc., that make difficult points as simple as A-B-C. Hand- somely and durably bound in half or full morocco leather (except as noted), and stamped in gold. e .°@ Pay-Raising Books o At Greatly Reduced Prices Business Management, 8 vols., 2500 pages, 1000 pictures. Was $52.50..........Now $29.80 Carpentry and Contracting, 5 volumes, 2138 pages,1000 pictures. Was $37.50,Now 19.80 Civil Engineering, 9 volumes, 3900 pages, 3000 pictures. Was $67.50......... Now 34.80 Electrical Engineering, 8 volumes, 3800 pages, 2600 pictures. Was $60.00 ....Now 29.80 Automobile Engineering, 6 volumes, 2600 Machine Shop Practice, 6 volumes, 2300 pages, 2500 pictures. Was $45.00 .... Now 21.80 Steam and Gas Engineering, 7 volumes, 3300 pages,2500 pictures. Was $52.50 .Now 24.80 Law and Practice (with reading course), 13 volumes, 6000 pages, illustrated. Was DR ae eile. 5 6%) wale :eo 4.6.6.0 476 Now 49.80 Fire Prevention and Insurance, 4 vols., 1500 pages, 600 pictures. Was $30.00, Now 14.80 Telephony and Telegraphy, 4 volumes, 1728 pages, 2000 pictures. Was $30.00 J) AES ae en 14.80 Sanitation, Heating and Ventilating, 4 volumes, 1454 pages, 1400 pictures. Was EEE re ers Now 14.80 Drawing, 4 volumes, 1578 pages, 1000 pic tures, blue prints, etc. Was $30.00. ..Now 14.80 Send No Money Shipped for 7 days’ Trial Yes, we'll gladly ship any set right to your home or office upon your simple request. Pay only ship- ping charges when the books arrive. Don’t senda penny until after you have used them seven days, then remit only $2.80 or return them at our expense. Pay balance at the rate of $3.00 a month—75c a week. . Act now—while these splendid books are being offered at 20% to 50% less than regular prices. This offer is open to every person within the boundaries of the U. S. and Canada. Grasp your opportunity— fill in and mail the coupon now. American Technical Society, Dept. XA-20, Chicago g American Technical Society, Dept. XA-20, Chicago, U. S. A. I

i MIM oe ccacemdenecckuel ry for 7 days’ examination, shipping charges collect. I I will examine the books thoroughly and, if satisfied, J will send $2.80 within 7 days and $3.00 each month, until I have paid the special price of f If I decide not to keep the books, I will notify you at J once and hold them subject to your order. Title not to pass to me until the set is fully paid for. I

1 Employed ES A ey ae ee RT:

HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY

pages, 2000 pictures. Was $45.00 .... Now 21.80 °

Laying Out an Octagon Quickly with a Steel Square HEN square stock is to be made into an octagon, the edges of the octagon can be laid out quickly with asteel square. Place the ends of the 2-ft. edge of the square at the opposite edges of the square stock, and mark at 7 and 17in. The edges of the octagon will pass through these points. This is quicker on large work than using the so-called octa- gon scale on a steel i Square and at the same time is suffi- ciently accurate.— R. E. DEERING, Clements, Kan.

SSA EDGES OF OCTAGON A time-saving meth- od for heavy work

Safety Slicer and Grater O PREVENT the housewife from grazing or cutting her fingers when slicing potatoes or grating vegetables, a frame can be constructed to hold a plain slicer or grater such as comomnly used. The front of the frame is grooved, as shown, to allow the tool to slide up and down. The back part of the frame is pro-

Reduces danger of cutting the fingers SLICER OR FEED BLOCK

vided with a feed block. The con- trivance is clamped to the edge of the table and the vegetable or other food product is placed between the block and the cutter. One hand moves the cutter up and down, while the other pushes for- ward the feed block. The slices or grat- ings drop into a pan placed on a chair directly underneath.—F. C.

Corner Guard for Walls N PLACE of the three-quar- ter round molding often used to pro- tect exposed cor- ners of a plastered wall, it is possible to make a very good substitute by nailing together three pieces of the much more com- mon quarter-round molding, as indicated. Carefully nailed together and well sanded, a corner protector of this kind is almost indistinguishable from a strip of three- quarter round molding.—O. M. A.

—— poar <TR TT. ppeere a a /GEND FOR ies) —==THIS FOR DON’T LOSE YOUR RIGHTS TO PATENT PROTECTION Before disclosing your invention to anyone send for blank form ‘‘EVIDENCE OF CON- CEPTION”’ to be signed and witnessed. A sample form together with printed instructions # will show youjust how to work up your evi- & dence and establish thesame before filing ap- plication for patent. As registered patent at- torneys we represent hundreds cfinventors all over the United States and Canada in thead- vancement of inventions. Ourschedule of fees willbe found reasonable. ‘The form “Evidence of Conception,’”’ sample, instructions relating to obtaining of patents and schedule of fees sent uponrequest. Ask for them,—a post card m will do. PATENTS AND “onscunnaron seer soca 274 Ouray Bldg. WASHINGTON, D. C. Originators of forms ‘Evidence of Conception.” “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 Ihadthem in, myself, only that I hear all right.’’ The Morley Phone for the DEAF is to the ears what glasses _are to the eyes. Invisible, comfortable, weight- less and harmless. Anyone can adjust it. Over one hundred thou- sand sold. Write for booklet and testimonials. THE MORLEY CO., Dept. 797, 10S. 18th Street, Philadelphia PROTECT PATENTS IMPORTANT © INVENTIONS Mason, Fenwick & Lawrence, Patent and Trademark Lawyers, Washington, D. C., New York and Chicago. Established over sixty years. Highest references. PATENTS. e REGISTERED PATENT ATTORNEY SINCE 1905 .% HARLES ASS.

Patent Litigation P ATENTS Trade Marks Copyrights Handbook of instructions, ‘‘How to Protect In- ventions,” sent free on request. R. H. FRAVEL, Patent Lawyer Formerly of the U. S. Patent Office Examining Corps Room 2503 McLachlen Bldg. WASHINGTON, D. C.

PATENTS BOOKLET FREE HIGHEST REFERENCES PROMPTNESS ASSURED BEST RESULTS Send drawing or model for examination and report as to patentability WATSON E. COLEMAN, Patent Lawyer 644 G Street N. W., Washington, D. C. sm a eg yn A LE

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Ss ee WE Se eT OU a . oe EC TE

HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY 123

Mounting Allows Spider-Web Coils to Be Changed Quickly B Bcses spider-web coil mounting was constructed for an experimental re- ceiving set in which it was desired to change coils with the least possible trouble. Two mounts are used, one sta- tionary and the other movable, and the coils can be snapped in and out instantly, all contacts being made automatically. This is more satisfactory than using tapped coils because the dead wire in tapped coils renders them less efficient. Two very short flathead brass machine screws are inserted in the_blank center

PP ate: MOVABLE MOUNTING BRASS / BRACKETS a ie - ~al)

“>=<= SHAFT STATIONARY MOUNTING Sa,

Strap mounting for stationary spider-web coil (at left) and for movable coil (at right) space of each spider-web form. The

method of insertion is to tap the holes for | the screws without running the tap clear | through, so that the fit will be as tight as possible. The screws are turned in until there is only about 1/32 in. of the shank out, and the end should project on the other side about the same distance. A very thin nut or a close-fitting washer is then soldered to the end of the screw, the end of the screw and the face of the washer or nut coming flush. The ends of the winding are led to the washers and soldered to the edges, one to each washer. The standards for the stationary coil are made of 14 by 1/16 in. brass, with angular notches cut in the facing edges, as shown, and the edges above the notches are tapered off. The distance between the standards should be such that when

the coil is snapped into place there will be | sufficient pressure against the screw heads to hold the coil firmly. A flexible lead is attached to the foot of each standard. In the case of the movable coil the ar- rangement is the same, except that the standards are attached to a fiber block, which is mounted on the shaft on which the assembly swings. Leads are taken from the lower ends of the brass strips in the same way as in the stationary assem- bly.—H. G. Worm Made with Lock-Washer N AMATEUR mechanic whorequired a worm for experimental purposes, pro- vided one quickly sia by the simple ex- wasree / pedient of solder- ===" ing a spring lock- washer on a rod, as shown. This nicely answered the purpose of a 4 OS S worm.—R. H. K. GEAR’

-7 SOLDER |

Seventy-eight Years of Practice HE firm of Munn & Company filed its first application for a patent in 1846, and for seventy-eight years has endeavored to keep pace with the inventive genius of the United States. An experience of many years is at your disposal. If you have an invention which you wish to patent, send your sketches or model together with a description of your device, explaining its operation, and you will receive prompt, courteous attention. Write for our Handbook on PATENTS A full and complete booklet on Patents, Designs, Trade-Marks, Foreign Patents, Copyrights, Labels and Patent Office Practice with an explanation about our methods, terms, etc. All communications strictly confidential Keep in touch with the inventions of the world by reading SCIENTIFIC AMERICAN The MONTHLY MAGAZINE with a special appeal to every man of inventive genius. Recent rulings of the Patent Office, descriptions of the latest patented inventions, legislation and court decisions affecting patents, are noted in this authoritative publication. MUNN & COMPANY Patent Attorneys 618 Woolworth Building, New York City Scientific American Bldg., Washington, D. C. Tower Building, Chicago, IIl. Hobart Bldg., 582 Market St., San Francisco, Cal. Van Nuys Building, Los Angeles, Cal.

NVENTORS , Send for our Guide Book, HOW TO GET A PATENT, PROTECT OUR IDEAS

and Evidence of Invention Blank, sent Free on request. Tells our terms, methods, etc. Send model or sketch and description of your invention for our Examina- ---- - --- ------------------------ tion and Instructions without | . | | charge. t ' SRM BBE ieikcs:are.oe oa. ee Kss mas see Re a Dept. 130, Washington, D.C. | cuv................-5. ee ’

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124 Is Seeing Believing? Mr. Fischler checked up on his eyes and was satisfied Most Edgeworth is sold by word of mouth —one happy smoker will pass the good word along to some less fortunate brother, and a new Edgeworth ‘“‘fan”’ is born. Sometimes, however, the human voice plays no part in the spread of Edgeworth popularity. Witness Mr. Fischler’s letter: Wellsboro, Pa. Larus & Bro. Co., Richmond, Va. Dear Sirs: Last summer while on my vacation, which was spent on Pine Creek, one of the best fishing streams in Northern Pennsylvania, I noticed a lot of discarded Edgeworth tobacco cans. Especially were they notice- able near the good fishing holes. When I returned home I bought Edge- worth and learned the reason for all those empty packages. Yours, Peter Fischler. We’re much too busy filling the blue tins here in Richmond to be able to follow them to the four corners of the earth. It’s a curious fact, by the way, that sRortsmen marked preference for Edgeworth. There’s something in the blend that strikes a@ responsive chord among fisher- men and nunters, campers and hikers. Perhaps some __ reader, himself a sportsman, can tell us why Mr. Fischler found ‘near the good so many Edgeworth tins fishing holes.”’ Be that as it may, “seeing is believing”’ with us just as it was with Mr. Fischler. Thousands of letters from pipe smokers are visual proof to us that in Edgeworth we are producing a tobacco that most men like. You may not find Edgeworth to your taste at all, but we think it probable that you will. Let’s try and find out! If you’ll write your name and address to Larus & Brother Company, 59 South 21st Street, Richmond, Va., we’ll send you, postpaid, free samples of Edgeworth Plug Slice and Ready Rubbed. What follows is a matter between you and your pipe! If you care to write us the name and address of your regular tobacco dealer, we shall very much appreciate your courtesy. To Retail Tobacco Merchants: If your jobber cannot supply you withEdgeworth, Larus & Brother Company will gladly send you prepaid by parcel post a one- or two-dozen carton of any size of Edge- worth Plug Slice or Ready-Rubbed for the same price you would pay the jobber. HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY everywhere show a | Novel Fishing Tackle Box Fitted with Electric Lights By Edwin R. Mason ON A recent fishing trip, I discovered a unique fishing tackle box designed for both day and night fishing. The box is about 14 in. long, 10 in. deep and 8 in. wide, made of thin, strong wood. It holds three trays, about 3 in. deep, each divided into two compartments. The bottom tray takes up only half the length of the box; the other half is given over to housing a flashlight battery, which furnishes the power for two lights. An ordinary flashlight is fastened to the bot- tom, a hole being cut in the end of the box to take the bull’s-eye. A small lever switch on the end operates this light. Another bulb is fastened on a swinging wooden arm in the lid. At the pivoted end of the arm is a thin strip of brass or copper, which serves as a contact when the arm is swung out over the trays after SPRING “BRASS STRIP 1 y ate ro o * \ t TTT, TTITTTITTT ITT — r ee FLASHLIGHT ----7 ~————4J Two lights—one attached to the lid—make this an ideal tackle box for night fishing the lid is raised. One wire runs from the bulb to this strip, while the other wire is coiled as shown, thus allowing the arm to be moved about. The heavy lines in the illustration indi- cate shallow slots sawed in the wood be- fore the box is put together. All wires are inserted in these slots to keep them en- tirely out of the way and afterward the slots are filled with putty. Contacts are made through the hinges. With a box of this sort, the fisherman is never without a light at night. The flashlight can be switched on when the box is being carried and no other light is neces- sary. When a hook or sinker is wanted, all that is necessary is to raise the lid, swing out the arm, and there is light aplenty. On the lid of the box is a brass handle that folds flush into a metal container when not in use. This allows the box to be used as a seat. Two snap fasteners, such as for suitcases, keep the lid fastened down when the box is being carried. The sketch is given merely to show the idea; the sizes and arrangements of trays and compartments should be chosen to suit the individual fisherman, as a box to be used in Indiana would hardly be the thing in the State of Washington. The artificial bait in different places varies considerably. To the Man With an Idea I offer a most comprehensive, ex- perienced, efficient service for his prompt, legal protection and the development of his proposition. Send sketch, or model and description, for advice as to cost, search through prior United States patents, etc. Pre- liminary advice gladly furnished with- out charge. My experience and familiarity with various arts, frequently enable me to accurately advise clients as to prob- able patentability before they go to any expense. Booklet of valuable information and form ee for properly disclosing your idea, free on 2 request. Write today. ee RICHARD B. OWEN Patent Lawyer 6 Owen Building, Washington,D.C. 2276-D Woolworth Building New York City We guarantee all other cars nearly [ols double present mileage, power and flexibility, make hills on high formerly difficult on low. Models for any car, eee tractor, marine or stationary engine. Makes old cars - ail than new. See wonderful milcage guaran- tees for other cars. Ford. ...34 mi. | Reo .. .24 mi. } Chevrolet .32 mi. Buick 4. .30 mi. | Chal’rs.23 mi. | Maxwl (25) .30 mi. Buick 6. .24 mi. | Olds. 6 .23 mi. | Nash6..... 23 mi. Hudson .20 mi. | Paige 6.20 mi. | Lincoln 8..17 mi. Hupp.. aE mi. Oaki’d6.24 mi. | StdbkrLt6. 23 mi. Dodge...28 mi. | Overl’d432 mi. | Cole8..... 7 end. If your car is not mentioned here send name and model for particulars and our guarantee on it. AGENTS WANTED. SENT ON 30 DAYS’ FREE TRIAL You can drive any car in heaviest traffic without shifting gears. Starts off on high in any weather without priming or heating—no jerking or choking. No more foul spark plugs or carbon in cylinders. No leaking of gas into crank case. Try it 30 days on our guarantee of money back if not entirely satisfied. No strings to our guarantee. YOU ARE THE JUDGE. Anyone who can handle a wrench can attach it. No boring of new holes or changing of operat- ing mechanism Write today. AIR- nh ggg CARBURETOR a1 951 Raymond Bld Dayton, Ohio, U - S. A, “MAKE MONEY. AT HOME you CAN make $1 to $2 an hour sige show | cards at home in your spare time. uic and easily learned by our new simple be semae No canvassing or soliciting. Weshow you how, guarantee you work at homeno matter where you live and pay you casheach week. Full par- prey and Kklet free. Write to-day AMERICAN SHOW CARD SYSTEM LTD. ital, $1,000,000 oronto, ‘Canada re wen and Fully Paid —_ 206 Adams Bldg. PATENTS TRADE-MARKS, COPYRIGHTS AND PATENT LITIGATION Write for advice and instruc- tions how to proceed, costs, etc. Hand Book with illustrations of 100 Mechanical ovements sent free on request. ALBERT E. DIETERICH Patent Lawyer and Solicitor Successor to Fred G. Dieterich & Co. 681A Ouray Bldg. WASHINGTON, D. C. As = of the oldest pat- ent firms in America we A | EN | S give inventors at lowest consistent charge, a ser- ce noted for results, evidenced_by many well known Plo of extraordinary value. Book, PalentSense, free. Lacey & Lacey, 648 F St., Wash., 'D. C. Estab. 1869. A TL. RNC ——-» a

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oe nee BF Se ———————— one wi. HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY Making a Signature Stamp from an Old Nail Buffer A NEAT facsimile signature stamp can be made f om a 10-cent nail buffer. The chamois first is removed and the packing underneath treated with type- writer stencil ink. A piece of typewriter stencil paper is prepared by writing the desired signature on it with a stylus or blunt pencil. This is placed on the inked surface of the buffer with the readable side cae ee a he The name is written on typewriter stencil paper, which is stretched over the buffer next to the ink and fastened with the metal band ordinarily used to hold the chamois. The stamp is used like a rubber stamp except that no stamp pad is necessary. It will sign letters quickly and will last for hundreds of impressions. The stamp also may be used for typewritten notices in place of arubber stamp.—K. B. MuRRAY. Homemade Clothes Rack HIS home- made clothes rack will support 25 or more bars. As many bars are inserted in the mortises as are needed at one time. When the rack is not in use, all are taken out and placed in the pocket. The stand then can be pushed into a convenient cor- ner.— A. M. Retouching Photo Negatives on Printing Frame rere taken by amateur pho- tographers often may be improved considerably by a little retouching and spotting. For this it is not necessary to purchase a standard retouching desk. Simply insert two long thin screws jnto the face of a printing frame, as illustrated, so that the frame will form a slanting desk. Stand it on a piece of white paper ora mirror to reflect up the light, and sit facing the light, with the lower half of the window shaded, if possible. Retouching varnish will be needed to give the negatives a “grip’’ for the pencil and a H.H. or harder pencil will be re- quired. An occasional spot can be taken out with thin drawing ink and a fine brush.—E. A. M. — NEGATIVE "REFLECTOR The retouching frame | Licensed for oe ——— PATENT NOTICE | | Cunningham tubes are || covered by patents dated 2-18-08, and others is- sued and pending. amateur, experimental and enter- tainment use communication. Any other use will be an infringement. | in radio 154 Lake Street, Chicago The care and operation of each model of Receiving Tube is fully explained in our new 40-page ‘‘Radio Tube Data Book.” Copies may be obtained by sending ten cents to our San Francisco office. Eilon HOME OFFICE: 182 Second St., San Francisco RADIO “TUBES } f The Standard Tube for all makes of | Radio Receiving Sets | ig is the Vacuum Tube that has made possible the broad and far-reaching appli- | cation of radio telephony, and that plays the | most important part in the operation of your | | receiving set. Radio messages from government leaders—from the heads of the world’s greatest educational insti- tutions or from those who stand foremost in the | arts of the world will serve to bring the human race _ f {nto closer contact. t Cunningham Vacuum Tubes, standard forall makes | of receiving sets—built by one of the world’s largest manufacturers with unlimited resources—are the | product of years of manufacturing experience and the creative genius of the engineers of that great scientific organization, the Research Laboratory of the General Electric Company. Now in Effect C-301A—5 Volts 1-4 Am- pere filament...... $5.00 |} C-299—3 Volts .06 amp Dry Battery Det. and tent Detector C-11—1.1 ! | | | | MNO ie sialeia siesta eta | C-300—5 Volts Gas oe | Volts. 25° } Dry Battery Det. and 30 Church Street, New, York nc | Amp. Special Base. . $5.00 } C-12—Similar to C-11 with standard base $5.00 | Prices on CunninghamRadioTubes || THE ALLEGRO SHARPENER for safety razor blades Makes Shaving a Pleasure ALLEGRO SHARPENER CO., Dept. 40 136 Liberty St., Allegro means ‘‘happy’’—why not be happy? This is the only device on the market combining a HONING and STROPPING feature, that posi- tively GUARANTEES A PERFECT, SHAVE. In a few seconds it gives blades fine KEEN EDGES that make shaving a TREAT. One Blade Lasts Six Months to One Year! Don’t throw away your blades. Treat them to an Allegro HONE-STROP and each blade will treat you to over 6 months daily shaving satisfaction. The Allegro pays for itself in less than a year and will last a lifetime. $5.00 will bring you, charges prepaid, the greatest money and temper saver you have ever known. Money returned if not fully satisfied after 10 days’ trial. The Allegro Sharpener sharpens either Gillette or Auto Strop blades. Specify which is required. Note: Liberal proposition to Agents and Dealers. New York City over deafness. and that their natural hearing been greatly improved. testimonials from Governors thousands of others. our confidence that we invite every sufferer to and there will be no charge. We ask for nodeposit. We do not shipC. O. D. our entire satisfaction, ighted with it, you are not asked to say FREE TRIAL, we mean FREE urchase, fals and FREE TRIAL request blank. 1306-H, Candler Bidg., 220 W. 42nd St., Makes the Deaf Hear Here is good news for the Deaf or people whoare hard of hear- ing. Science has at last triumphed s. Unless your Audi- tory Nerve is entirely destroyed, the Acousticon will enable you to hear as perfectly as anyone whose hearing is normal. Thousands who have been Deaf for years report most gratifying results—many say they can hear the slightest bye as We have Bankers, Ministers, Lawyers and So great is Try it 10 Days FREE You are not asked to purchase this remarkable invention until you have tried it 10 days FREE, until you have proved to your entire satisfaction that it is what you need and want—until you are absolutely certain that it will enable you to hear all sounds clearly, Then, if you wish, you may keep and pay for it, otherwise return it Send No Money send you this latest scientific invention entirely at our own risk and expense for 10 days FREE TRIAL. We don’t ask you to pay first and then refund your money if you are not satisfiedy Wesend you the Acousticon with- out cost or obligation. It must prove its own merits to Unless you are amazed and de- When we ‘REE TRIAL, sosend name and address at once for descriptive literature, testimon- Dictograph Products Corporation

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cs | BUILDING TRADES HANDBOOK | BUILDING TRADES’ HANDBOOK 263 illustrations. On ly A reference book for every man con- nected with the building trades. Contents :— Blue Prints, Weights and Measures, For- mulz, Mensuration, Geometric Drawing, Structural De- sign, Materials of Masonry Con- struction (stone, brick, terra cotta, lime, cements, sand, mortar, con- crete), Carpentry and Joinery, Roof- ing, Steel Square, Plumbing, Heat- ing, Estimating, Architectural De- sign, etc. Thousands sold. Complete—prac- tical—thorough. Easy to under- stand. Pocket size. *#\ Just fill out the coupon below— slip it into an envelope with a dollar bill and mail, and this 409-page I. C. S. Building Trades’ Handbook will come speeding to you by return mail. You run no risk Money back if desired International Correspondence Schools 1 I 1 Box 7693-C, Scranton, Penna. I ! I enclose One Doliar. Please send me ! ! post-paid—the 409-page I. C. S. Building ] 1 Trades’ Handbook. It is understood that { if I am not entirely satisfied I may return I this book within five days and you will l | refund my money. | i ! 1 | SERGE one cee 1 i | ! Address.... ! ae lide saeiaiinacig inane naan eine nha ee ee ene nm says Kemper Slidell. Frank DePries made over $325 profit in one day. L. D. Payne averaged $20.77 profit for 217 days. F. E. Mendenhall worked half time and made $100 \ a week. . E Findlay ran up es commatesions in a few months from $100 them to over $500 per month. Every Home, & Auto Owner, Store and Factory a Live Prospect—Keeton, Howard, and others, never sold Fire Exe tinguishers before. Our special training course starts you on . Toad to success first day. If now employed, we can show you how to make big money during spare time. No Experience pa pone Get our new Sales Plan—find out how to make ‘money. Territory going fast—write today! THE FYR-FYTER CO., ‘15 Fyr-Fyter Bldg., Dayton, 0, POPULAR SCIENCE MONTHLY Greatest Engineering Feats (Continued from page 27) later in the construction of what still remains the largest project of the kind ever undertaken—the Assuan Dam, which irrigates the Valley of the Nile in Egypt for its entire length of 700 miles. The Nile is one of the world’s great streams, being exceeded in length only by the Mississippi. An attempt to impound the water of so large a river never before had been made. When completed, 22° years ago, the Assuan Dam was the world’s greatest reservoir and its capacity was increased 21% times in the next 10 years. In magnitude, construction, and utility, this huge reservoir takes rank with the great public works of all time. HE dam, which is of granite masonry set in mortar, crosses the head of the Assuan cataract of the Nile in a straight line. It is 114 miles long, 82 feet thick at its deepest aiithe, and as originally con- structed was 23 feet wide at the top. Its original height from foundation to coping was 131 feet, but later 26 feet was added to this. Before it was enlarged, its capacity was 235,000,000,000 gallons— equivalent to a billion tons of water. There are 180 sluice openings, to control the intake and outlet. These are opened when the river floods, and the water flows in without losing the silt it carries, an important feature, since the valley re- quires mud for fertilizing. When the clear flow of winter comes, the sluices are closed and the dam filled. This requires about 100 days after December first. When the water is released, it always issues from the dam at the bottom, carry- ing with it the enriching silt. The dam adds more than one-third to the natural flow of the Nile in times of low water. Construction of the dam was begun in | February, 1898, and it was completed in | December, 1902, a full year before the specified time. This bears eloquent testimony to the smoothness and effi- ciency with which the work was prose- cuted, despite imposing obstacles that arose from time to time. I must mention also the Roosevelt Dam, completed in 1911, in Salt River Valley, near Phoenix, Ariz. This dam is located at the mouth of a canyon, 67 miles from the nearest railway. The materials of constructior were produced almost entirely in the vicinity. Rock was blasted from 40 miles of surrounding terrain. Lumber camps and sawmills were established. Electric plants were installed. Two farms were operated to feed the workers. Even a cement mill was erected. HOUGH neither so large nor serving so great a territory as the Assuan Dam, the Roosevelt Dam is a con- spicuous achievement. It has made a vast area of waste land available for farm- ing. It has caused land that was literally worthless to acquire a value of hundreds of dollars or more an acre. It is a mighty link in the great chain of water-storage developments that are bound to exert a profound influence on the future history of this country, since they convey to man (Continued on page 127) Tobacco Stained Teeth Instantly Whitened New Safe Way No need now for yellow, discolored, spotted tobacco-stained teeth. Bleachodent Combina- tion costs just a few cents and removes un- sightly stains in three minutes at home. Leaves teeth white, lustrous, clean and _ flashing. Recommended everywhere as quicker, surer, safer than old-fashioned scouring methods which injured the enamel. Bleachodent Com- bination contains a marvelous mild liquid to loosen stain coats and a special paste which not only removes them, but used daily prevents formation of new stains. Only a safe mild preparation like Bleachodent Combination should be used on soft, sensitive teeth which stain and decay easily. Acts only on stains— not on enamel. Be sure to ask for Bleachodent Combination by its full name. Distributed by Bleachodent Dental Laboratories and sold by drug and department stores everywhere. SOLDERALL SOLDERS ALL JOINTS PERMANENTLY 25¢ STORM. KING LIGHTNING=ARRESTER APPROVED BY THE NATIONAL BOARD of FIRE UNDERWRITERS i $y00 AT ALL DEALERS Down For 2 H-P. WITTE (Throttling Governor) Easy Termsonbestengine §& built. Burnskerosene, istillate,pasoline or gas. Change ower at will. Equipped = h_the famous WICO eauete. Other sizes, 2 to 25 H-P.—all styles. | today for my Big Engine Book, Sent free—No obligation on your part. WITTE ENGINE WORKS 2221 Oakland Avenue, - KANSAS CITY, MO. 2221 Empire Building, - PITTSBURGH, PA. BUCHSTEIN’S FIBRE LIMB soothing to your stump— strong, cool, neat, light. Easy payments. Guaranteed 5S Years a Send for Catalog Today deformities, P. BUCHSTEIN:CO., 610-3rd Ave.; So. Minneapolis, Minn.

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Greatest Engineering Feats (Continued from page 126) the land from which coming generations will derive their food and clothing. These, then, in my opinion, are the greatest engineering works of modern times. To say that they will be surpassed in the future ‘scarcely can be called venturing a prediction. Rather it almost is to give voice to an obvious fact. Man’s future demands on engineering are bound to be greater and greater, and, as in the past, it is certain that engineering skill will meet each new demand. Already several projects of tremendous magnitude seem certain to be executed in the near future. Oddly enough, one of these amounts virtually to the recon- struction of the Panama Canal. To make drastic improvements on this magnificent example of engineering may seem like gilding the lily; yet it is more than probable that eventually a sea- level canal across the isthmus will be necessary. Traffic through the canal is limited at present. The water of Gatun Lake is reduced 25 per cent during the dry season through evaporation and the operation of the locks. Fifty vessels can be accommodated in one day, but it is unlikely that 50 vessels could pass through every day for a year without seriously decreasing the depth of the channel, due to the amount of water needed to operate the locks. SEA-LEVEL canal would solve this problem permanently. Also, it would prevent the canal from being rendered useless by an earthquake or by destruc- tion of the locks in time of war. Another gigantic undertaking that may be expected is the construction of a tunnel or bridge across the Straits of Dover between England and France. A tunnel probably will be the means selected, although, from an engineering standpoint, a bridge would be entirely feasible. Either one would rank with the engineering marvels of all time, for the distance across the Channel is 31 miles, and the depth of the water from 90 to 165 feet. The gigantic engineering feats that this country may see accomplished within a few years are bridges across the Hudson River at New York City and across the Golden Gate at San Francisco. Both of these projects have been discussed seriously, and one can be almost certain that some day they will be undertaken. A bridge at either city would of necessity be the greatest in the world, since spans of 3009 or 4000 feet would be included in its construction. Thus it would appear that one need not wander far into the realms of fancy in forecasting engineering wonders for the future. Engineers even now are giving serious consideration to the practicability of harnessing the tides. Extracting the heat from the center of the earth, storing up and utilizing the energy of the sun, trans- mitting electric power through great dis- tances without wires—these are only a few of the accomplishments toward which science is gradually working. Future generations will see these things done, for the impossibility of today is the actuality of tomorrow. POPULAR SCIENCE MONTHLY 127

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Radio Wherever You Go Vacation— Outing~—Touring |

This year go with Radio. ge fish, hunt, tour with Radio. Make your vacation complete. Liven up the rainy days and_long, dull evenings. Take the ne w, wonderful Ozarka Portable, aan Distance Receiver with you. Get the sports returns—the con- certs—the special features of hundreds of broadcasting st atic ns And, best of all, you'll have it for home use when you return, Ozarka is built for long distance—1000 miles is not unusual, Simple to operate. Convenient and light to carry. Only weighs 15 lbs. complete. Cc ase _ § 16x10x5 inches. Completely equipped with aerial, ‘‘A’’ and ‘‘B”’ Batteries, three No. 199 tubes, and one set of head phones. Ready for instant use. Price com- plete ready to listenin, $65.00. Extra phones, $5.50. Big demand, Order at once. Se nd $10.00, pay balance on delivery. Satisfaction guaranteed. Local Representatives Wanted Ozarka Radio offers the greatest opportunity to make money. Big money—easy sales. Over 1800 Ozarka Agencies now doing wonderful business. Some territory now open. You're interested, so write today for the ‘‘Ozarka Pian.’’ Don’t fail to give name of your county.

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128

Wurlitzer,

in your for a week’s free trial the instrument, show it offer because we want you ments, the result of 2 instrument building. ak especially of the ease playing, a feature that is of i as the professional. Easy Payments your instrument. Speci tor, ete. — everythi at practically the cost of instrument alone. Send for New Catalog The greatest musical ottabe ever published ! Over 3,0 articles — every known in- ment described and illus- trated; many of them shown in full colors. Gives you lowest prices and all details of Free Trial, Easy Payment plan. r. sent F — no obliga’ Rand thi is Coupon

TTY ay Warlitzer Instrument Own Home ) We may now have any Wurlitzer instrument your own home. Examine your friends, play it as much as you wish. No obligation to buy — no expense for the trial. We make this liberal see for yourself the r instru: R\ quality of Wurlitzer instru. Artists of the highest standing in every sphere of music use 4 Wurlitzer instruments and _ re-7g@ —— eo them to others. They portance to the amateur as well¢ If you decide to buy after the week’s free trial, payments are arranged in sma!l monthly sums. A few cents a day will Rae for offers on complete outfits—velvet lined case, all accessories, self-instruc- ng you need IREIZER mnt ‘|, 200 Years Ago &, the little \, - of Shoeneck lived Hans Adam Master Violin Maker. His shop was a gathering place for - ~ gnusicians of the time, for he was 0") @ true craftsman. When he died his shop passed into TT * the hands of his eldest son, and for seven generations, down resent day, the descendants of Hans Adam Wurlitzer have bis work. In every Wurlitzer instrue ment you wiil find a quality a character, that could not come from mere excellence of manufacture. It is the heritage of these seven generations of music craftsmanship. G in Sd to

to 00 years’ experience in musical FF AC of im- the

fst and description of every THE RUDOLPH WURLITZER CO., Dept. A-178 % 120 W. 42ndSt.,NewYork 117 E. 4thSt., Cincinnati 329 S. Wabash Ave., Chicago 250 Stockton St. peseagar Send me, absolutely free, your new Illustrated catalog, with own musical 9 Also i how I may try any instrument in my own home and pay or it in emall monthly sums. No obligation.

POPULAR SCIENCE MONTHLY

ment (State Instrument in which you are interested) Copzright, 1924, The Rudolph Worlitzer Co.

He Sees by Radio (Continued from page 30) “Curiously enough, the invention that has made the most money for me probably is the one that interested me least as an inventor. This is the spiral wound paper container for liquids that you see every- where in grocery stores, drug-stores, candy shops, restaurants, and similar establishments. “I was one of the first men to work out a self-starter for an automobile. Also, I built the first automobile seen in Washing- ton—about the time that Haynes, Win- ton, and Duryea were doing their pioneer work. It wasasteam car. I built Wash- ington’s first sight-seeing automobile, too —the first ever built in the world for all I know. In those days,” reflected Jenkins with an odd smile, “I could develop an invention all right enough, but I didn’t know what to do with it when I had it.” Things have changed, though, since those early days, and one needs but a cursory look about Jenkins’ orderly labo- ratory to be convinced that the inventor has indeed become the business man. His shops and workrooms are spic and span as the decks of a battleship—and they are filled with young women and young men. IVE me the young men,” he said enthusiastically. ‘‘The young ex- perimenter doesn’t know enough to be afraid of failure. Given a difficult mechani- cal problem, an older man is likely to permit formulas to convince him that the thing is impossible, and surrender without a fight. The young man, though, hasn’t time to bother with incomplete formulas. While the older man is poring over them, the young man has finished the job that was theoretically impossible. In that one respect, I’ve remained young myself.” Jenkins is about 55 years old. He looks like a professor, but talks like a business man—in quick, incisive phrases that ex- press his meaning exactly. Midnight labor has no terror for him. Twenty-four hours a day fit into his routine without friction. In the face of this custom of continued labor it is not odd that he is a stranger to the usual recreations of the tired business man. He has From March to November he pilots his own airplane in flights in the vicinity of Washington, and says he finds two hours in the air a more satisfactory vacation than two weeks on the ground. Mrs. Jenkins is his frequent companion in flight. If radiovision succeeds, Jenkins will join the very select list of inventors who have achieved two great inventions. Ordinary pictures Jenkins now can pro- ject by radio over distances limited only by the power of the broadcasting station to which his instruments are attached. Moving pictures, too, though with less fidelity to the original. But in the trans- mission of actual scenes he is limited now to silhouettes—black and white pictures. This, though, he declares, eventually will give the halftone values also, and I accept his word. His Quaker father taught him not to boast, and, after the astonishing things I saw the other day in his laboratory, I am ready to believe any- thing told me by the man who created moving pictures.

Drive This p Beautiful Raceabout J Instead of Your OLD FORD Choice of Four Colors ; Fiat or the : ee | ; a Bullet Nose Rad- y ~ F i iator Shell. Send . ves. y p for 1924 Free Cat- alog of New Auto Acces’, Bodies and Speed Equipment. Direct from Factory, AMERICAN TOP AND BODY CO., Beech Street DELPHI. IND,

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TYP EWR ITER| i BARGAINS! A real writing machine standard key Ow ui t f 1,00 raha ie cat taal he ss—Rebuilt Machine Dept., Oliver Typewriter Co. 810 Oliver Typewriter Bidg.,Chicago Squab Book FREE Squabs selling at highest prices ever known. Greatest market for 20 years. Make money breeding them. Raised in one month. We ship everywhere our famous breeding stock and supplies. Established 23 years, Write now for big illustrated free book, How to Make Money Breeding Squabs: PLYMOUTH ROCK SQUAB CO, 616 H St., Melrose Highlands, Mass. MAKE INTO Your FORD fic SPORT CA Other types down to $3.50. Famous sure fit, i size patterns and picture instructions show how. easily convese your Ford into this fast, saucy Sport Car as hundreds have ved with a few dol of material from the io

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Sie IARKOGRAF Protect your tools from theft. Write any name, engrave “1 6 aa 4 any design on tools and metal with z iat ly miacteiaty like writing on paper with “” Pod BS or pencil. Complete outfit oy __ F 3.50, prepaid anywhere. Interest- ole Z ing descriptive circular 5 free. Write ail to-day. Agents wante Arkograf Pen Co., 1171- A East Stark St., Portland, Oregon Easy Now to Make and $4 00 Repair ElectricalAppliances. § > Genuine Nichrome Wire paid This resistance wire is the business end of standard electrical appliance. 27 feet guaranteed up to 660 w: atts, 110—120 volts, 6 amps. With this you can make or repair your own electrical ranges, furnaces, sadirons, toasters, curling irons, waffle griddles, etc. Complete package with copper and mica washers, nuts, screws, and wi instruc- tions sent prepaid for One Dollar. Or order eee D. and pay few cents extra postage. ALLIED PACT ORIES

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=a DURHAM | FP _ Variable Grid Leak At dealers, or postpaid et St., Phila. Durham & Co., 1936 Mar Ford Runs 57 Miles on Gallon of Gasoline A new automatic and self-regulating device has one invented by John A. Stransky, 2300 Fourth Pukwana, South Dakota, with which automo- biies have made from 40 to 57 miles on a gallon of gasoline. It removes all carbon and prevents spark plug trouble and overheating. It can be installed by anyone in five minutes. Mr. Stransky wants agents and is willing to send a sample at his own risk. Write him today.—Adv.

ees = aero atari: ee en —<—

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ut tD ur she at. ito nd ry. ~~ Foss EB St a OM Saas | a rope re ee A ee eee A ce POPULAR SCIENCE MONTHLY AG ENTS a Genuine Gold Leaf Letters GUARANTEED TO NEVER TARNISH For store fronts, office windows, Bank windows, Office Doors, Panels, Board Signs, Trucks, Automobiles and Glass Signs of all kinds. Any- one can put them on and make money right from the start without previous experie nce. All you have to do is to show your samples; the letters are very attractive and easy to sell. Letters costing 4c sell for 25c. One agent says: ‘‘Your Letters are the best thing I have seen in years; I have made $125.00 the first week and still going, strong.”’ Paul Clark says: ‘‘Smallest day $28.70." H. Gilder made $835.00 in six weeks. $60 to $200 a Week GENERAL AGENTS—!It is easy to appoint sub- agents for this line. We pay you 20% cash commission on all orders we receive trom local agents appointed by you anywhere. We allow you 50% discount on your own orders. You can sell to nearby trade or travel all over the country, as you please. Large demand for window lettering everywhere. Write today for free sample, full par- ticulars and liberal offer to general agents. Metallic Letter Co., 433-AN. Clark St., Chicago Home Protection with an Caeiac e ASTRA Automatic will cost little Nearly every man wants a gun in the house—he feels better able to protect his family. We are able to offer these Genuine Astra guns at special prices because we bought before recent tariff raises became effective. Really fine guns, beautifully finished, hard hitting. Use standard ammunition. Order direct from U. S. importers. $7.75 25 cattore—7 shot—C. 0. Q. Automatic. 8.95 25 calibre—7 shot—Astra Automatic. 9 25 calibre Astra with triple safety. 10.95 32 calibre—10 shot Astra, extra magazine. 16.95 32-20 and 38 cal. swing-out cyl. revolvers. We guarantee every gun against defective work- manship; brand new; of Drop Forged Steel Throug he out. Before buying any weapon INSIST on this guarantee. SEN NO MONEY unless. you wish. State model eet postman on delivery lus postage. Satisfaction guaranteed or money re= unded. Write for new firearms catalogue. CALIFORNIA TRADING CO. Dept. 16, Terminal Bldg., Los Angeles, Cal. SEND FOR OUR BIG FREE BARGAIN BOOK of the best Auto Supplies LL made! You'd be surprised if you knew our sources and names of manufacturers. EVERYTHINGS——= Mase! BitenesSpetiges SOD ES — Bum mpers — T: book exactly Testrates in in colors’ 20% ep thousands ‘4 yey 4 oana ever you n or want in Equipment. Every le backed by, ot our Legal ; nding Guarantee of absolute satie~ per jon. Ss everywhere. Get o.. thae inside of chie Price-Saving business. Postal card or letter brings this book—FREE! Be sure to ask for BeeEw vORn J AUTO & RADIO SUPPLY Co Washington at Peoria S Chicago, titinols AUTO SUPPLIES Nature’s Magic in Radium (Continued from page 43) astounding feat the wonder element performs—transforming itself from one substance into another entirely different through the alchemy of nature. The way in which what may be called the radium family produces its successive generations indeed is amazing. Old Father Uranium, parent of this remarkable family, goes through a series of changes, becoming what chemists call Uranium X;, Uranium X), and Uranium 2, then Ionium, and eventually Radium. Then Radium goes through its own series of metamorphoses, becoming po- lonium, and at last Lead. In all, there are 16 more or less long- | lived and sturdy generations between | Uranium and Lead, and, as may be | assumed, the process is not completed speedily. As a matter of fact, it takes more than 6,000,000,000 years! salah lig amazing property of trans- forming itself slowly into lead nat- urally raises the question whether, eons ago, the earth may not have had a super- abundant supply of radium; whether, in short, all the lead in the world today may not have been pure radium. Possibly, although science says that if this ever | was so, the earth was a place vastly | different from the earth we know. It |; must have been a tiny, flaming sun, or possibly a part of the sun. The latter hypothesis frequently is offered as explaining the origin of our earth. It assumes that the earth is a piece hurled from the sun or some other giant heavenly body, and that its surface, gradually cooling, became inhabited by the “‘life spores” that had been floating through the ether. If there is anything in this theory, we may wonder whether the life spores themselves may not have been emana- tions from radium; for science has . . | demonstrated conclusively that radio- activity bears a distinct relation to the | very elements of life. For example, certain seeds subjected to the action of radium rays, produce plants of un- | usual vigor with extraordinary rapidity. The reason science believes radium never existed on earth in any large | quantities in a free state is because its | chemical properties would seem to make that impossible. Obtaining pure radium is exceedingly difficult, and it is virtually impossible to keep it pure because of the avidity with which it reacts with air. In consequence, commercial radium is pro- duced only in the form of its salts—the bromide, the chlorid, the carbonate, and the sulphate. Radium’s principal practical use, aside from its employment in making luminous paints, has been for medical purposes. The possibility that radium might be use- ful in medicine occurred to Pierre Curie, husband of its discoverer, in 1901. Even before that Becquerel, suffering a severe | burn when he carried a tube of radium in his waistcoat pocket, noted its peculiar action on the body tissues. Henri Dominici, however, must be called the father of radium therapy. In 1906 he discovered that radium rays, (Continued on page 130) can do if he will make up his mind to be strong—any olden days it took years to develop a strong, healthy 129 EARLE E. LIEDERMAN as he is today How Strong Are You Can You Do These Things? Lift 200 Ibs. or more overhead with one arm; Bend and break a horse shoe; Tear two decks of playing cards; Bend spikes; Chin yourself with one hand. Can you do any of them? I can and many of my pupils can, It is remarkable the things a man really min, It is natural for the hum: in body to be strong. ‘It is criminal to be weak.”’ I have taken men who were ridiculed because of their frail make-up and de- veloped them into the strongest men of their locality. | WANT YOU FOR 90 DAYS These days call for speed. It once took four weeks to cross the ocean—necw it takes less than one. In body. I can completely transform you in 90 days. Yes, make a complete change in your entire physical make-up. In 30 days I guarantee to increase your biceps one full inch. I also guarantee to increase your chest two full inches. But I don’t quit there. I don't stop till you're a finished athlete—a real strong man. I will broaden your shoulders, deepen your chest, strengthen your neck. I will give you the arms and legs of a Hercules. I will put an armor plate of muscle over your entire body. But with it comes the strong, powe rful lungs which enrich the blood, putting new life into your entire being. You will have the spring to your step and the flash to your eyes. You will be bubbling over with strength, pep and vitality. A Doctor Who Takes His Own Medicine I was a frail weakling myself in search of health and strength. I spent years in study and research, analyz ing my own defects to find what I needed. After many tests and experiments, I discovered the secret of progressive exercising. I increased my own arm over 614 inches, my neck 3 inches and other parts of my body in proportion. I decided to become a public benefactor and impart this knowledge to others. Physicians and the highest authorities on physic: il culture have tested my system and Pronounced it to be the surest means of acquiring perfect manhood. Do you crave a strong, wellpronoctianed body and the abundance of health which go with it? Are you true to yourself? If so, spend a pleasant half hour in learning how to attain it. The knowledge is yours for the asking. Send for My Book “MUSCULAR DEVELOPMENT” iT 1S FREE It contains forty-three full-page photographs of myself and some of the many prize-winning pupils I have trained. Some of these came to me as pitiiul weaklings, imploring me to help them. Look them over now and you will marvel at their present phy siques. This book will prove an impetus and a real inspiration to you. It will thrill you through and through. All I ask is 10 cents to cover the cost of wrapping and mailing and it is yours to keep. This will not obligate you at all, but for the sake of your future health and happiness, do not put it off. Send today—right now, before you turn this page. EARLE E. LIEDERMAN Dept. 1306, 305 Broadway, New York City EARLE E. LIEDERMAN Dept. 1306, 305 Broadway, New York City Dear Sir: I enclose herewith 10c for which you are to send me, without obijigation on my part whatever, a copy of your latest book ‘‘Muscular Development” (please write or print plainly). Name ..... da tmnnue wincemcnarae an Address. - - - i sac a Seine ae =

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dns SPARE hat minis lh AO Ca | dy |

21 Perfect Jewels Adjusted to Positions Adjusted to ture Adjusted to Isochronism Adjusted to the Second 25-Year Gold Strata Case Tempera- We will send this famous watch, express prepaid, for you to examine, to inspect, to admire, to approve, without one penny advance payment. Examine the watch and be convinced it’s the best watch buy you ever saw. Just a small payment down, the balance in easy MONTHLY payments. You use the watch while paying for it. Save 4% to 1% of Your Money By purchasing this Famous Santa Fe Special Watch. Not only are you saving money from the present day prices of watches, but you can still secure the “Santa Fe Special’’ Watch at the same low prices and terms that have made our watches famous. . . Ladies’ Wrist Watches This Artistic dependable Ladie’s Wrist Watch, fitted with genuine Illinois Spring- field movements. 35 me ~~ oe het oe Or CTD a a 2 ot 06k lee

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4 ‘ 0. lif. ————— — pe a —— Portable Radio Receiver (Continued from page 68) ment of from 200 to 400 ohms. Numbers 8 and 10 are the rheostats with fine con- trol. Tubes 12 and 16 are controlled by rheostat 8, while tubes 21 and 24 are con- trolled by rheostat 10. Number 9 is a double-circuit jack, while No. 11 is a single-circuit jack. Anti- capacity jacks were used to conserve space. Numbers 12, 16, 21, and 24 are the tube sockets. The designations Fl and F2 have been assigned arbitrarily to the fila- ment terminals merely to avoid confusion in wiring. It makes no difference which filament terminal is called Fi or F2. Numbers 13 and 17 are radio-frequency transformers. These should be of a type designed to cover the entire broadcasting range. UMBERS 14 and 27 indicate the screws and nuts used to fasten the baseboard of the set to the cover of the suitcase. Two other fastenings are used close to the panel edge of the baseboard. Washers should be used on the outside of the case to prevent tearing of the cover. Number 15 is the positive B battery binding post. Numbers 18, 22, and 23 are audio-frequency transformers. Number 18 may have a high ratio, but numbers 22 and 23 should be of the low ratio type. Number 19 is the crystal-detector mounting. Number 20 is a .001-micro- farad fixed condenser. Number 25 is the positive A battery and negative B battery binding post, while No. 26 is the negative A battery post. In the radio-frequency transformers, the primary terminals are indicated by the letter P, while the secondary terminals are indicated by the letter G. The terminals on each side of the letter are those of the winding indicated by the letter. The number 2 refers to the outside terminals of the windings, while the number 1 refers to the inside terminals of the coils. If your transformer terminals are marked P, B, G and F, the P corresponds to P2; the B corresponds to P1; the G corre- sponds to G2, and the F to G1. In some audio transformers the letter A is used to denote one terminal of the secondary winding. In others, the letter F is used. WITCH 3 is provided with seven switchpoints; switch 5 with eight. The last switchpoint of switch 8, that is, the one nearest the bottom of the panel, is left unconnected. It merely provides a means of disconnecting the switch-arm of switch 5 from coil 4. When the set is to be used with a loop aerial, it is not desirable to use the coil in parallel with the loop. By setting switch-arm 5 on the blind con- tact, the coil is disconnected from the circuit. Each switchpoint of one switch is con- nected with the corresponding switch- point of the other. Each tap of the tuning coil then is connected with the switch- point connectors, so that in effect each tap of the coil is connected with a switchpoint of each switch. In this way each switch can be connected with any tap of the coil. (Continued on page 132) POPULAR SCIENCE MONTHLY bigger quarters. sharpened mower. W. F. Kendt, 1476 Main St., Buffato, writes: position. “ANEW BUSINESS—BIG BUSINESS A Business to Enthuse Over— The “‘Ideal’” Lawn Mower Sharpener A wonderful invention that sharpens lawn mowers scientific- ally—quickly—perfectly; does the work as nothing else can. Fred C. Milkert of Melrose Park, Ill., writes: “The Ideal Lawnmower Grinder put me in business, starting in the base- ment of my home and forcing me now for the third time to move into Today the dream of my life—a shop of my own—is realized. With a machine like yours and a little hustle any man can have a business of his own and be independent.”’ You Start Now No town is too small. dull—owner doesn’t know where to get them sharpened. Mowing the lawn dreaded because of dull or improperly Lawn mowing is healthful, invigorating and pleas-’ ant when Moweris “Ideally” sharpened. Youdo the work scientifically—you are in big demand. Lawn Mowers Sharpened to People glad—owners delight in mowing lawn with mower sharpened on an “‘Ideal.”” Mower runs light—click-click-click and the grass is cut. Build permanent business for yourself. Start now! Write Today Get our proposition Free We have detailed trated book tosend you. Write today for our pro- Lawn mowers are Razor Edge — USE THIS — MAIL IT TODAY The Fate-Root-Heath Company 802 Bell St., Dept.39, Plymouth,O. Please mail at_ once details of your complete proposition. illus- The Fate-Root-Heath comene & MAEM oo ioc crete ton nacsncus Nedaeoauanee Dept.39, 802 Bell St., Plymouth, COCO Reem ree ee reer e saree esses eee SESE ESSE EEeeeese® ) {{ OFAMIGHTY es i DISCOVERY Sir Oliver Lodge says he hopes this discovery will not become generally known until mankind has sufficient wisdom to handle the power that it will loosen. But scientists have already tapped this source of power! Not yet harnessed perhaps but yet plain enough that ANY AVERAGE PERSON can toa large exe tent demonstrate it in daily life. With the use of this ENERGY you can accomplish anything hu:nanly possible. This FACT has been proven by the actual experience of thousands of people during the last twelve months in whose hands we freely placed this amazing discovery. You not only ‘‘get the idea” but it applies itself to your affairs within a few days. Nothing Impossible Literally thousands of people changed their lives | almost overnight by this revelation. With this secret Col. Adams of Salt Lake City made over $4,090 in a few days. Unless this power will immediately and practically WORK for you, unless you can demonstrate it as clearly asa child demonstrates electricity by turning on the electric light, IT IS WORTH NOTHING TO YOU. For all men are not equal. Doubt, fear, suspicion, distrust, irresolution are chains that make slaves of many. Five Days’ Free Trial Simply send your name, postcard will do, we will mail you postpaid, CLEAR, POSITIVE, SIMPLE instructions that you can begin applying IN A VERY FEW HOURS. You have five days to study and examine it without cost. If it proves valuable in obtaining concrete results we leave it to you to pay us within 5 days what in your judgment it is actually worth to you or what you honestly can afford to pay. If you think it is worth nothing, pay nothing, simply return it. This plan seems strange and unusual. But the power and secret are ALSO strange and unusual. You WRONG only yourself if you delay. The CARNAGEY INSTITUTE H. C. CARNAGEY, President 504 Hayes Bldg. Dept. 508 Kansas City, Mo. Aahatae SEND NOMONEY 10. Genuine Diamonds WEDDING RING No. 6177—3-Stone Diamond, White Gold. , $29.00 att LADIES’ RING No. 6405 — i 18-kt. White ~ Ging at Se $9000 ES) Our white gold looks and C weurs like platinum, MEN’S RING Vz ; White No. 6107 in - kt rold) Toy ind Green Gold shank. Spool Pract size $95 00 INITIAL OR EMBLEM RING NOAH sone Gold with 2 Genuine Diamonds 4/100 | Ts) | eae ® 14-kt. White Gold Top. Gold initial or emblem inlaid in Genuine HOPE RUBY, or BLACK ONYX. Furnished inall initials (Old English) and in all lodge emblems. Send size of finger and ring desired will be sent for in- Spection. Terms:—Month- ly payments if desired. W ( BUFFALO — JEWELRY MFG. CO. “The Mail-Order House’’ Dept. A Brisbane Bidg. This reaietered Ew _Kusrantees you genuine diam BUFFALO,N.Y. 8 ¥ G&G M S W Lotter

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: ; : ; ' t : 24 “Dont tell me you never had a chance! “Four years ago you and I worked at the same bench. I realized that to get ahead I needed special training, and decided to let the International Correspon- dence Schools help me. I wanted you to do the same, but you said, ‘Aw, forget it!’ You had the same chance I had, but you turned it down. No, Jim, you can’t expect more money until you’ve trained yourself to handle bigger work.” There are lots of “Jims” in the world—in stores, factories, offices, everywhere. Are you one of them? Wake up! Every time you see an I. C. 8. coupon your chance is star- ing you in the face. Don’t turn it down. Right now over 180,000 men and women are preparing them- selves for bigger jobs and better pay through I. C. S. courses. You can join them and get in line for promotion. Mark and mail this coupon, and find out how. Mail the Coupon To-day! ~ INTERNATIONAL CORRESPONDENCE SCHOOLS Box 7691-C, Scranton, Penna. Without cost or obligation on my part, please tell me how I can qualify for the position or in the subject before which I have marked an X: BUSINESS TRAINING COURSES [jBusiness Management [1 Salesmanship [jIndustrial Management [) Advertising j Personnel Organization [| Better Letters [} Traffic Management [|] Show Card Lettering { )Business Law [_] Stenography and Typing []Banking and Banking Law [} Business English [ JAccountancy (including C.P.A.) 0 Civil Service [] Nicholson Cost Accounting [] Railway Mail Clerk [ | Bookkeeping + Common School Subjects Private Secretary [j High School Subjects Spanish () French (J Glustrating TECHNICAL AND INDUSTRIAL COURSES QO Electrical Engineering 0 Architect C) Electric Lighting ( Architects’ Blue Prints Mechanical Engineer ( Contractor and Builder Mechanical Draftsman ( Architectural Draftsman (Machine Shop Practice (J Concrete Builder Railroad Positions (Structural Engineer Gas Engine Operating Chemistry [) Pharmacy te pe Automobile Work Sanaikeres O Mining O Airplane Engines rricul me g >, Steam Engineering (Radio [Muthemstien | ty nai toe ii cab sab coda tdepirkussvcuktobccusaubvadedgebbenosereesiiacivednece Street 3-6-°24 Address TN san calhvaiabibiceseciaambanbeksbceaucescasisscbiers ccdseidepnicdeneedense Persons residing in Canada should send this coupon to the International Correspondence Schools Canadian, Limited, Montreal, Canada POPULAR SCIENCE MONTHLY Portable Radio Receiver (Continued from page 131) After the taps are connected with the switchpoints, the top end, or zero tap, of the winding is connected with the G ter- | minal of socket 12 and the A, or stationary plate, terminal of condenser 6. ‘TRE aerial post 1 is connected with the switch-arm of switch 3. A wire then is used to connect the following terminals in the order named—the ground post 2; the switch-arm of switch 5; the B terminal of potentiometer 7; the rotary plate ter- minal B of condenser 6, and the Gi ter- minal of transformer 13. Next, lead a wire along the bottom of the set, connecting post 25 with the C terminal of potentiometer 7. Branches then are used to connect this wire with the Fi terminals of sockets 21 and 24. Another wire is run along the back of the baseboard, connecting post 25 with the F2 terminal of socket 12. With this wire the F2 terminal of socket 16 is con- nected. The next step is to connect the negative A battery post 26 with the A terminals of rheostats 8 and 10, and with the A ter- minal of the potentiometer. The A ter- minals of transformers 22 and 23 are con- nected with this wire by short lengths. A wire running along the baseboard connects the B terminal of rheostat 8 with the F1 terminals of sockets 12 and 16. Another wire connects the B terminal of rheostat 10 with the F2 terminals of sockets 21 and 24. OW connect the P terminal of socket 12 with the P2 terminal of trans- former 13. The G2 terminal of trans- former 13 is connected with the G terminal of transformer 18. Then connect the G terminal of socket 16 with the A terminal of transformer 18. The G2 terminal of transformer 17 is connected with the catwhisker terminal B of erystal-detector mounting 19, while the A or crystal terminal of the mounting is connected with the P terminal of transformer 18. The detector circuit is completed by connecting the Gi terminal of transformer 17 with the B terminal of transformer 18. Now connect the P terminal of socket 16 with the P2 terminal of sennmormer Aue the G terminal of transformer 22 with the G terminal of socket 21; the G terminal of transformer 23 with the G@ terminal of socket 24; the P terminal of socket 21 with the P terminal of transformer 23; the P terminal of socket 24 with the A terminal of jack 11. Now you can run a bus wire practically the length of the set to serve as the com- mon connector by which the terminals of the various instruments are connected with the positive of the B battery. Start the wire at binding-post 15; run it to terminal P1 of transformer 13, then over the center of the baseboard and | e above the set to the B terminal of trans- | | GIBSON, INC, -» 2605 Parsons St., Kalamazoo, Mich. former 23. Then connect the B terminal | of jack 11 with the A terminal of jack 9 | and with the B battery bus vrire men- | tioned in the preceding sentence. | The Pi terminal of transformer 17 is (Continued on page 133) BRUSH Ay - A brush expert saysthey are the best Hair Brushesmade. They are penetrating. They go all through the hair to the roots and stimulate growth. They make a beautiful radiantsheen. The glory of woman is made more glorious with Whiting-Adams Hair Brushes. Send for Illustrated Literature JOHN L. WHITING-J. J. ADAMS CO. N Boston, U.S.A. : Brush Manufacturers for Over 114 Years and the Largest in the World Rp af 6eé 99% Applause Cards ‘*___Station W-E-A-F signing off. If you have enjoyed the artists’ program, won't you write in and tell them?” By all means! Quickly and easily with ‘‘Ap- plause Cards.”"* They’re handsomely printed mailing cards. All ready for you to fill in with your comments, sign, and drop in the mail box. Keep a pack of them near your receiving set. You can use ‘‘Applause Cards’’* liberally be- cause they are FREE AT YOUR RADIO caps S. ‘Applause Cards’’* were originated by this c ompany, makers of the popular Dictogrand oud Spe ake rand the Aristocrat Dictograph lie adset. The only ‘‘Applause Cards’’* are Dictograph Copyrighted ‘‘Applause Cards.” A big FREE package of them awaits you at your dealer’s. Or if he has not yet stocked, WRITE US, GIVING HIS NAME and we’ll ship you a generous supply of ‘‘Applause Cards’’* free, pre- paid, direct. Dept. I-6 DICTOGRAPH PRODUCTS CORPORATION 220 West 42nd Street, New York City *% Copyrighted Banjo ey wilt The new Gibson Mastertone, now being adopted by leading profession- als like Charles McNeil of the famous Isham Jones Orchestra, pictured 4; here, is the one banjo which com- bines the snap and ‘‘pep”’ required with big volume, exceptional carry- ing power, and a really musical quality of tone. Easiest to play be- cause of Gibson’s exclusive features. Free Trial; Easy Payments! 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H ON at cs i iit >, now ession- amous ctured 1 com- quired carry- usical ay atures. its! tenor- ndola; Mich. 71S Pr ge meen mma Sort See aN A RT a eee ane cas. ERS a, Sa ———__— POPULAR SCIENCE MONTHLY Portable Radio Receiver (Continued from page 132) connected with one of the outside ter- minals, B, of jack 9. One of the inside terminals, D—the one that makes contact with the outside spring B of jack 9—is connected with the P terminal of transformer 22. The other inside terminal C, making contact with outside spring A, is connected with ter- minal B of transformer 22. HE wiring is completed by connect- ing the fixed condenser 20 into the plate circuit of tube 16. One terminal of the condenser is connected with the lead connecting the P1 terminal of transformer 17 with the B terminal of jack 9. The other is connected with the lead to the positive B battery post 15. In some cases you may find it necessary to connect a fixed condenser of about .00025 microfarad between terminal G2 of transformer 13 and the G terminal of tube 16. For the battery connections, the nega- tive of the A battery is connected with post 26; the positive A battery and nega- tive B battery terminals with post 25, and (from 45 to 90 volts) with post 15. of the receiver, so it is very important that a good, sensitive crystal be used. O CHANGE the circuit into one hav- ing one stage of transformer-coupled radio-frequency amplification, a vacuum- tube detector, and two stages of straight audio-frequency amplification, it is neces- sary only to lift the catwhisker from the crystal, disconnect the secondary leads of transformer 18 from the grid circuit of tube 16 and connect into the break be- tween the G2 terminal of transformer 13 and the G terminal of tube 16, a standard grid condenser and leak. The set is tuned much as any other standard set. The approximate setting for wave length is obtained by the two in- ductance switches, and the finer adjust- ment by using the variable condenser. The signals can be cleared and brought in with greater volume by adjustment of the potentiometer and filament rheostats. The programs then can be brought in with best results by readjusting the crys- tal to its point of greatest sensitivity and by slightly readjusting the other controls. If the regulation type of wire aerial is used, the aerial is connected with the aerial post 1 and the ground or counter- poise is connected with post 2. If a loop aerial is used, one end should be con- nected with the aerial post 1 and the other end with the ground post 2. When a loop aerial is used, switch 5 should be set on the blind contact so as to disconnect coil 4 from the circuit. If you prefer dry-cell tubes when using the set. as a portable outfit, and the storage-battery tubes when using it at home, adapters can be used. When the summer tour is over, the receiver can be mounted in a cabinet. NEXT month’s issue Mr. Calcaterra will tell how to build an unusually light combination portable receiver, using either one or three tubes. the positive terminal of the B battery | The crystal detector is the very heart | 133 Months You “‘learn by doing” — 2 ata Hiciienee Siew a sammeieaaiiiia school—in a national institution of 25 years’ standing—located in the Electrical Center of the World. You learn by actual work on $200,000 worth of electrical apparatus—no books—no lessons— JUST WOR experience or education. capable of commanding big pay. electrical concern. yourself and make $3000 to $20,000 a year. of Free Railroad Fare. information—send it today! Coyne Electrical School, Dept. A-136 1300-1310 West Harrison Street, Chleoee, Illinois You work under the eyes of experts and receive individual instruction. You need no previous And this is the only way you can become an Electrical Expert Earn $200 to $600 a Month By this method of practical training, a man is “‘on the job” just as if he were employed by an He is not ‘ ‘green’ ” when he goes out to look for work because Coyne training duplicates the actual work “‘out in the field’. the big money. Covne will train you to make $200 to $600 a month or go in business for It’s the EXPERTS that are getting Earn While You Learn We help students to secure jobs to earn a good part of their living expenses while studying. Scholarship which enables you to to study as long as you want, and assists you to a position after graduation. Send for Free R.R. Fare Offer . Send today for the big Free Book and details of our special offer s Make up your mind today that you are going to learn electricity in a practical way so that you will be an ELECTRICAL EXPERT. The coupon brings full We give you free a course in Radio, a Life ROTTER LoL s “Coyne ElectricalSchool ae West "chictee t ote Cniciwe, tie ie ‘ase se is me free aa bi Ss catalog and your special offer o} free railroad fare. > SS > Ss Ss M4 G} “yy 4, > & ~ = BY D4 « ° ° Clean off the threads, apply SMOOTH-ON No.1 screw into place and the nuisance is stopped for good. Experienced motorists make one job of resetting every grease cup on the car. Doing this costs less for the Smooth-On than the cost of one lost cup, and the lubrication is more dependable. Apply the same treatment to nuts and hub caps and you'll know that they are going to stay tight until you want them off. Smooth-On No. 1 special locking device, as it is not affected by vibration, or temperature changes. Get Smooth-On No. 1 in 6-o2., I-lb., 5-lb. or 10-1b. lin at nearest hardware store. SMOOTH-ON MFG. CO. Dept. 58 547 Communipaw Avenue Jersey City. N. J. is as effective as a road shocks Oe Evinrude builds the lightest . P. motor made, He could phe build the lightest 1 H.P, or2H.P. motor, But ne knowa | that less than 8 H. is not enough for the speed a. wantor the safety you have a right to ex- pect in rough waters, or with heavy * ads. In the Elto Twin you get not “ only ease in carrying, but one half more power and much more speed. “STARTS with a TOUCH” No other outboard motor gives you ine stant startin every time, and safe rude der steering, porte both hands free to troll or cast. The Elto is the safe family motor. No danger of sudden capsizing of boat while reversing. Weed-free selfe Trouble proof carbue retor. The Elto fits in carrying case with- out taking apart. Write for free catalog, Elto Outboard Motor Co. uf.

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134 POPULAR SCIENCE MONTHLY

Here Are Correct Answers to Questions on Page 64 1. No. A balloon rises because it is lighter than air. But the air gets thinner, there- fore lighter, as one goes up. The balloon will rise only until it is as heavy as the air it displaces.

2. Because their leaves cannot get enough water. The air in the house is warm and dry and the leaves dry out. The stem of the fern is small and does not contain enough water tubes to supply the fern. 3. Because the back part of the eye has the property of reflecting light much as a mirror does. If you stand in a lighted doorway and a cat in the dark looks at you, the light from the doorway is re- flected in the cat’s eyes.

4. At one place you can see two or three ' - thousand. From all over the earth about Generations of travelers in Europe have = i * Um 6000 stars are visible. geen women washing clothes, like the woman i A) ¥ in this illustration, on the banks of rivers. — Fim 8 5. There is no evidence that they do, They are indications sometimes of the forgotten past, but not of the future.

6. One of its main functions is to control ® the amount of sugar in the blood. When a t _ r1ver wor omeremies you eat sugar, it is absorbed and carried to the liver. The liver converts it into a ? substance called “‘glycogen.’’ Then when or shall Ou the muscles need more sugar for food, the > liver converts a little of this glycogen back into sugar and releases it into the blood so that it can be carried to the |

Too many women, abroad, are muscles, still washing clothes like this. 7. Salt has the power of lowering the temperature of melting ice. The mixture , of salt and ice gets much colder than | They +40) to the river. Our mere ice and water would get. | American rivers are being 8. No. It has none of the characteristics | i of living matter. It is merely a secretion Back of every great trained tocome to us. Water- produced by the living hair cells in the step in woman’s pro- i. : scalp. gress from a drudge wheels drive electric genera- nee ' to a free citizen has = dj 9. Uranium is one of the elements like been some labor-sav- tors—thus water is supplied radium, the atoms of which explode and ing invention. Back = y produce atoms of lead. The percentage of most inventions in to your home, and electric of the atoms that explode in a second or electricity’s progress . in a century is known. Accordingly, if from a mystery to a current runs the washing you know how much uranium and how | utility has been the re- S _ much lead there is in a certain sample of | searchof General Elec- machine which has banished rock, you can calculate just how many tric Company scien- ‘ years it has taken that much uranium tists and engineers. SO much toil. to produce that much lead. Calculations like this for the earliest known rocks give an age of about 1,600,000,000 years. The earth as a whole is, of course, older than these rocks. It may be as much as six or eight billion years old. 10. Helium, the non-inflammable gas now used for filling airships. This was dis- covered in the sun in 1868 by the spec- troscope, but was not found anywhere on earth until 1895.

11. Chloroform has an unusually strong affinity for nervous tissues, including the tissue of the brain. It collects there and Agents $84 a Week affects this tissue so that nerve impulses h The New Serenola The fastest selling musical inven- | CaN NO longer pass through it, neither onog 7 = fion the world has ever known. | pain sensations through nerves, nor . 10 times its price. Big dem thoughts through different parts of the 2 Needs NYOIIs Easily carri chp se aedag brain. After a certain period, the blood Cleanest, most highly-refined oil Built in--just like a'suitcase. guaranteed. Low price. Must | slowly removes the chloroform from the for typewriters, sewing machines, radio equipment, bicycles, Satisfy customers or money back, nervous tissue and the nerves and brain Quick, Easy Sales guns, etc. Lubricates, pre- vents rust. No color, Rapid promotion from Agentto | Te able to work again. stain or odor. Will not District Manager. It’s a perma- gum, Fine polish for nent thing--keeps right on goin i ribrati Bige-pavs big money week zoing | 12. Heat is due to the vibration of the week, month after month. No | molecules. When a substance gets hotter, iano cases, automo- iles, etc. Buy Nyoil of your dealer or write

time lost. Make be money right | the molecules in it vibrate faster. This your work. No waiting for eom- | pushes them a little farther apart and . a Suneinent you every day. We have bundreda pretty soon they get so far apart that a ‘rom oO @ day. ver 10, - ; iti = struments already sold. Don't pass iy ean ce 2h their fixed positions are lost and the sub opportunity. Write or wire us for territory. stance becomes a liquid. | PERRY-LUDLOW CO., S-4047, Dayton. Ohio

W. &. NYE, New Bedford, Mass.

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Ts 4 hter ere- loon > air ugh and n of tain n. has asa hted ‘Ss at 3 re- hree bout do. the ntrol VN hen rried nto a when 1, the -ogen 0 the » the r the xture

than ‘istics ‘etion n the | s like e and ntage nd or ly, if | how ple of many nium ations six or e gas is dis- spec- pre on strong ig the ‘e and pulses either , nor of the blood m the brain of the 10tter, This t+ and t that e sub-

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Adventures in Home Ownership (Continued from page 45) closet are reached. The dining-room is about the same as in the other plans.” Marion now had the last sheet spread out. there’s a fine big, well lighted owner’s chamber with two closets and a storage room in the gable over the maid’s room. There’s a linen closet in the hall, the bathroom at the rear as before, also two more good chambers with a closet each.” “That about completes the case for this house, I believe,” said Jim. ‘‘What’s the | verdict?” ‘‘Again very favorable,” I replied. “But which house do you like best?’ Marion asked rather impatiently. ‘As houses, I like them all,’’ I answered. “For your needs, however, it seems to me, that all three cases ought to be recon- sidered together.” “That’s true,” said Jim. “But couldn’t one of these houses be used as the basis for slight alterations?” ‘“‘That’s just what I wanted to suggest,” I replied. ‘“‘The last house you have shown me is distinctive, picturesque, and good, but it seems to me that the simple dignity of the second one—the quaint lean-to type—will continue to please you longer than the other, and the floor plans are simpler, better, and give you more. With slight alterations, which your ar- chitect would charge little for, you could have everything you need and the whole house probably could be built for about $12,000, fully equipped.”’ “How would you change the plan?” asked Jim. Marion the sun porch she desires so much. You might inclose the large open porch in glass. Then, to have an open porch in addition, you could borrow the very ingenious rambling idea of the third house—join the garage with the dining- room by means of an attractive covered porch. This will make the house look larger, add to its attractiveness, and at the same time give you a sheltered passage from the house to the garage. “Again, I noticed that Marion. was greatly attracted by the built-in sewing- table, which converted the front end of the upstairs hall of the first house into a sort of sewing-room. You might do the same thing with the light and roomy dressing-room adjoining the owner’s chamber in this second house. It would make an ideal sewing-room. “These are just a couple of suggestions for slight alterations to give you what you want. Probably others will occur to you before you start to build.” “By George,” exclaimed Jim, ‘“‘you’ve hit the nail on the head! I’ll get the architect started on the alterations to- morrow. Meanwhile we’ll look at some lots both near-by and a little farther out.”

Read in next month’s issue how Jim and Marion let the contract for build- ing their permanent home and how the house was equipped. ——

“T TPSTAIRS,” she went on, “you see |

“Well,” I explained, ‘‘first to give |

POPULAR SCIENCE MONTHLY 135

For longer, stronger battery service LL dry cells are not alike. Columbias last longer. Intensely energetic. Regular jacks- of-all-trades. Do everything, from firing engines to invigorating doorbells and tending furnaces. Strong and quick to pick up energy when the cir- cuit is open. Always fresh, because they sell so fast. Economical too. You'll buy fewer batteries if you insist on Columbias. Great for radio dry cell tubes. Columbia Dry Batteries are sold by electrical, hardware, radio and auto accessory shops, marine supply dealers, implement dealers, garages, gen- eral stores. Fahnestock Spring Clip Binding Posts on Columbia Ignitor at no extra cost to you. NATIONAL CARBON COMPANY, Inc. New York San Francisco Canadian National Carbon Co., Limited Toronto. Ontario for— Doorbells and buzzers Gas engine ignition Ringing burglar alarms ‘Tractor ignition Protecting bank vaults Starting Fords Calling Pullman porters Firing blasts Running toys Motor boat ignition Telephone andtelegraph Heat regulators Lighting tents and Electric clocks . outbuildings Radio “A”

a8 mane eqeerese® Fa Cobunbie ow EN — eg = oo ot steel case bat- | | : tery defies water é 4 £aT ANS \ 'Gxition. rapio and weather.

INSPECTED TESTED; RELiaBLe

|

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136 POPULAR SCIENCE MONTHLY lake a Kodak with you You'd like to remember a day like this and pictures won't let you forget. Any Kodak is convenient to carry, easy to work and fun to use; you'll get good pictures from the first. Autographic Kodaks $ 6.50 up At your dealer’s Eastman Kodak Company, Rochester, N. Y., rie Kodak ci ART COLOR PRINTING CO,, NEW YORK

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COLGATE'S Shaving Stick % in Mak ose WT Se I aR “HANDY GRIP’ ano REFILL AAG ALM RN IE For Comfort, Convenience, and Economy When we say to you that the Shaving Stick has important ad- vantages over shaving preparations in any other form, we can do so without bias, for we manufacture shaving sticks, powder and cream. In its attractive nickel box, our “Handy Grip” Shaving Stick is most convenient for traveling. It will not crush when packed, and it makes a wonderful lather for easy shaving. It is not uncommon for a Colgate Shaving Stick to last more than a year in daily use. The famous “Handy Grip”, with a trial-size shaving stick in nickel box, sent for 10c. When the trial stick is gone, buy Colgate “Refills” for the price of the soap alone, 25c. COLGATE & Co. Established 1806 NEW YORK Truth in advertising implies honesty in manufacture ee

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45 minutes toasting develops its aristocratic flavor — the enormous production makes possible its democratic price LUCKY STRIKE ‘IT'S TOASTED”

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