"I'M GLAD I've got a good job," thought Warren Cady, as he stayed overtime at the office the afternoon of pay-day to go over his bills and draw checks to cover them. Let's look over Warren's shoulder and see what his monthly crop of bills is. Here is the itemized list of the checks he drew: Monthly mortgage and interest payment Gas, electricity, milk, etc Mrs. Cady's monthly allowance .
Life of Tubes Is One of the Features That Is Determined in Institute's Tests
Popular Science Monthly GUARANTEE
IF FEW people recognize just how important is the work of vacuum tubes, they all do realize that the life of these radio essentials is often entirely too brief. The causes for the short life of some tubes have been definitely determined, but let us see what the vacuum tube does while it is living.
"I AM glad to reach the end of your articles on ‘Dick Byrd—Adventurer.’ I am surprised that a magazine of the authority of POPULAR SCIENCE MONTHLY should stoop to become a part of the Byrd hero-worship ballyhoo. He must have talked you into those articles just like he talks nonthinking business men to finance his hair-brained flights.
Supremacy of Planes Challenged as Europe Prepares Flying Liners for Trans-Atlantic Service, and U. S. Navy Lays Plans for Two Huge Lighter-than-Air Ships
H. C. DAVIS
THE destruction in the Arctic of General Nobile's comparatively small semirigid dirigible balloon the Italia emphasizes the fact that there is in the world today only one great Zeppelin-type dirigible in commission. That is the silvery veteran Los Angeles, built for us by Germany as our trophy of the war.
Stupendous Project, Equal to the Greatest in Europe9 Will Make the Continents Hours Instead of Days Apart
GROVER C. MUELLER
NOW Central America and the West Indies are to be linked to the United States by air. Contracts for carrying U. S. air mail to Haiti, Santo Domingo, and Porto Rico over one new route and to Mexico, Central America, and Panama over another have just been awarded to Pan-American Airways, present operator of a Key West-Havana airline, and this company’s fourteen-passenger monoplanes, largest ever built by the Fokker Company, will shortly inaugurate mail and passenger service.
Twenty-five Years of Experiment at Last Make Home Screen Pictures in Natural Hues a Simple Process for Everyone
A Blotter That Erases Ink
ROBERT E. MARTIN
EPOCH making inventions usually turn out to be astonishingly simple. All the revolutionary 4 developments of radio, for ex ample, hinge on the discovery of what takes place when three simple pieces of metal are inclosed in a glass bulb and the air is pumped out.
Engineers Ingeniously Reach Across a 500-Foot Canyon to Bridge a Tourist Highway into a Painted Wonderland
WITHIN a few weeks motorists will drive over the first bridge ever flung across the canyon of the Colorado River. Looking down between the sheer walls of Marble Gorge to the turbulent stream 500 feet below, tourists in northwestern Arizona will witness a combined spectacle of scenic grandeur and engineering achievement unsurpassed anywhere.
THE Amazing Adventures of Nine "Robinson Crusoes" and Their Native Wives on an Uninhabited South Sea Island Have Altered Age Old Scientific Beliefs. From Their Descendants There Dr. H. L. Shapiro, Eminent Anthropologist, Has Discovered Upsetting Facts About the Results of Marriage Among Relatives
EDWIN W. TEALE
RETURNING from one of the strangest quests in modern science, Dr. H. IL. Shapiro. anthropologisL at the American Museum of Natural History, brought to America, not long ago, fresh facts about the mysterious laws that govern the birth and destiny of human beings.
The Thrilling Story of Modern Combat with Flames, as Seen by New York's Great Veteran Chief
HENRY MORTON ROBINSON
FIRE in mid-ocean! A flame-crazed bolt of lightning had just splintered the topgallant mast of the clipper ship, Santa Anna, reeling up the east coast of South America after a frightful passage around Cape Horn. Exhausted from her battle with icy hurricanes, the Santa Anna now rolled like a blazing barrel in an Antarctic thunderstorm twelve hundred miles off her course.
An Expert Tells How Photo-Electric "Eyes" Bring Television Nearer and Promise to Harness the Sun
E. E. FREE
ONE sunny afternoon a few weeks ago a young man stood on the roof of a building in New York City waving a tennis racket in the air. He might have been doing his daily dozen, but he wasn’t. He was exercising an eye—not his own eye, but the newest eye of science; the one that promises to make television really useful.
Experiments Show That the Heart Pumps Five and One Half Quarts Through the Human Body Every Minute
GEORGE LEE DOWD
A PUZZLE of physiology, three centuries old, was solved the other L day when four physicians of the University of Louisville. School of Medicine, Kentucky, succeeded in measuring the output of the human heart. The marvelous little engines that drive our bodies, they found, pump blood at the rate of about five and one half quarts every minute! This discovery was the result of experiments by Drs. W. F. Hamilton, s J. W. Moore.
French Scientist Demonstrates How Electric Power Can Be Produced by Harnessing the Ocean s Varying Temperatures
POWER from the sea—power in vast, incalculable quantities—is the glittering promise held out by Georges Claude, famous French physicist with revolutionary industrial successes already to his credit. For at an experimental plant on the Meuse River, near Liege, Belgium, Claude has just reported that he is successfully drawing forty kilowatts of electric power directly from the water's natural heat.
New Art and Industry Produces Decorations For Buildings Which Defy Time and Elements
TIME was, the creation of architectural ornament was wholly a matter of the mason’s trusty chisel and stubborn stone. But scientific development in cement and concrete has produced a stone which may be given any shape, texture, or color without reference to a chisel until the final dressing.
Here Are the Details, Advantages, and Weaknesses Sashes, Casements and Plain, Plate and Ultra-Violet Glass
JOHN R. McMAHON
KING Rollo was a merry old soul, but he needed cash, and the royal treasurer said: “Sire, there is none, and we’ve already taxed the daylights out of the people." “Is that so? Ha! I have it!" chuckled the gay monarch. “I'll tax their daylight! Put five doubloons on every window in a man’s house.
Powerful UltraViolet Lights, Which Can Be Used in the Home, Are the Latest Tools of Physicians
A PUBLIC-SPIRITED English man, Lieutenant Colonel G. S. Hutchison, took five poor pit boys from British coal mines on a "sunbath" outing to Switzerland, where the natural sunlight has long been known to he exceptionally beneficial to health. The lads grew amazingly strong. but obviously this expedient was impossible for all the boys and men deprived of sunlight by their work underground.
MARLEY never did learn the identity of the chief conspirator in the plot to humiliate Old Bill Stone, the locomotive engineer, but just the same he fired the culprit. He couldn't have missed him, for he butted an entire department into an engine pit and chased every grimy one of them to the timekeeper's office for his money. No further investigation was necessary.
Government Achieves Amazing Results Breeding and Raising Fish Just as Farmers Do Livestock
THAT expanse of ocean you see from the deck of a liner is not the wet desert it seems, but a rich, desert seems, but a rich, rolling meadow, teeming with life. It is a meadow that covers more than three-fifths of the world, everywhere more than a thousand feet deep, with a green, energy-producing pasturage for uncounted forms of life.
Mysteries of the Patent Office Explained—Why Many a Valuable Idea Cannot Be Protected and How Ignorance May Cost Fortune
P. A. CARMICHAEL
MILES from a garage on a little traveled road with a flat tire. Miles, also, from the nearest filling station. What was he to do? He had tire patches and cement, but what good were they without a pump? Presently a farm boy came along who carried a little pump to rent for fifteen cents.
SWINDLERS are finding radio, mysterious to most people, a fertile field. Thou sands of radio listeners have been misled in the pur chase of buried antennas purporting to prevent static, bring in more distant stations, and get rid of interference.
The Answer Depends on You, But Here Are the Facts to Guide You
ALFRED P. LANE
"WOULD you advise me to build a radio receiver or to buy a regular factory built set?" To that question, asked us many times daily, there can be no definite answer. It depends altogether on the individual. Some men would never consider building their own receivers.
A Loudspeaker Cord That You Can Walk On—Adjusting the Voltage in Eliminators—A Good Method of Sharp Tuning
YOU can operate a loudspeaker at a point some distance away from the radio receiver without in any way impairing the results. In fact. the only problem is that of running the necessary wire. If the radio receiver and the loudspeaker are on the same side but at different ends of the same room, the wire can, of course, be run along the baseboard.
EARLY types of radio receivers rarely included any choke coils in their construction. Modern sets, both factory-built and home-assembled, make considerable use of them. choke coil is not a new piece of apparatus. It was well knowTn long before broadcasting, but the importance of the choke coil in forcing the electric currents in the radio receiver to keep to certain definite paths was not fully appreciated until tone quality came to be so all-important.
RESISTANCE units are commonly rated by the number of watts of current they will safely dissipate in the `form of heat. While this method of rating allows you to figure the safe current-carrying capacity of the resistance, it would be better for the radio amateur if the manufacturers would specify the current-carrying capacity in milliamperes.
IN BUILDING a B-eliminator or a power amplifier unit combined with a B-eliminator, there are undoubted advantages in having adjustable resistances so that the various voltages can be changed to suit conditions. However, the difficulty in most circuits providing for adjustable voltages is that there is nothing prevent the adjustment being carried too far.
RADIO fans who are interested in getL ting the last possible fraction of strength out of a distant signal may well take a tip from the expert photographer. When the photographer focuses the image on the ground glass of his camera he rotates the adjusting knob back and forth so that the lens moves first beyond and inside the point where the picture is sharp.
Powerful Electromagnet Operating Directly on a Moving Coil Reproduces Music with Greatly Increased Fidelity
ANOTHER revolutionary change in radio loudspeakers is impending. The cone type speaker rapidly drove the ordinary horn type into oblivion. Now the still newer dynamic cone threatens to drive out the cone. The cone replaced the horn because it reproduced music more faithfully.
Famous Gridiron Star Explains How the Forward Pass Has Given to the Game a New Strategy and Greater Thrills
Science Slashes Coal Bills
EDWIN B. DOOLEY
THE whistle sounded for the second half with Cornell and Dartmouth deadlocked 14 to 14. Fifty thousand fans had howled themselves into football hysteria a few minutes earlier as Cornell had battered its way by sheer power to two touchdowns. Molinet, the Cuban fullback, had smashed our line to pieces with his catapult plunges.
Engineers Fight Against Odd Sizes in Hardware, Film, Masonry, Plumbing, China, and Even Bedsheets
HYATT E. GIBSON
AMAN veiled into the ’phone: “This is Fire Chief of Millville! Send help quick ! Big fire getting away from us. For God’s sake, send all you got!” “Sure thing!” shouted back the firehouse official in the neighboring town of Orono. “Our engine and truck will be with you in twenty minutes. I’ve shot the alarm.
A BILLION - DOLLAR job that will require three years for completion is the riprapping of the lower Mississippi River, now well under way following last spring's devastating floods. It is the most stupendous engineering project of the kind.
1. "Who was the first man to fly across the English Channel? When was it done? 2. Which type of craft is the older, heavier-than-air or lighter-than-air? 3. What country leads in air mail development? 4. How is a parachute opened? 5. How does the fuel consumption, in miles per gallon, of a light airplane compare with the fuel consumption of a light automobile? 6. What is an airway radio beacon?
FROM a vast 41-acre waste of mos quito-infested New Jersey swamp land, just across the Hudson River from New York City, soon may rise a great city of industries and homes, larger in area than New York herself. A project recently announced by the Regional Plan of New York and pictured on this page calls for streets and skyscrapers, parks and waterways, flying fields and residential districts.
Any ordinary nozzle fits in this hinged device which is adjustable to any position from vertical to horizontal. Its standard ends in a long slender spike, which can easily be driven down by hand power without marring your lawr
With 5-lamp ornamental lights Washington Boulevard takes from State Street, Chicago, the honor of the world’s best lighted street. Each pole has 10,500 candlepower. In one of the lamps is the daughter of A. F. Dickerson, of the General Electric Company, who helped design them.
This door is kept bolted while the lady of the house opens the swinging, hinged sash and talks with the stranger through the protecting iron grille which is in the outer face of the door. Between the grille and the sash is a bronze screen, an additional convenience.
The thief who drives off in this parked car is in for a surprise. The owner has turned the license plate to a vertical position with a lever, which is then locked so that no one can restore the plate to its proper position without the key. In Australia, where the device is used, the policeman knows what a vertical plate means.
Pressure of buttons and electric controls operate the $4,000,00C car classification system recently installed in the Boston yards ol the Boston & Maine Railroad, replacing many trainmen. President Hannauer, of the road, is seen pointing to one section of the system at the ceremonies which lately inaugurated its use.
This new device speeds the work of clearing off old paint to provide a perfect surface for repainting. The long cord is run from a socket. The block, which contains a heating element, softens all the paint so it can be readily scraped off, as at the right, but the wood is not burned nor even scorched.
This new glove, woven from strands of steel, was invented by a physician employed by a large meat packing concern where the accident department records showed many cut hands and fingers. It provides excellent protection, yet is said to allow ample freedom of movement at the same time.
Little metal bridges over street gutters have been devised by I. G. Bench and J. D. Boyd, sheriff of Utah County, Utah, to receive front wheels of cars and thus prevent their blocking the flow of water during storms and during gutter irrigation.
This novel case has cigarettes in one side and in the other checkers, which, when not in use, repose under the board, which forms a lid that retains them. The lid is hinged so that one half can be lifted.
Clubs that have been bowed through carelessness, such as letting them lie iron down all winter, are strapped into the straight grooves of this English invention. Left there a sufficient time, they are “cured.
Milk Preserved by Radio—Human Body a Dynamo of a Million Volts—Tears a Powerful Germicide
THE newest use found for radio is to keep milk from souring. Prof. Karl Seidel, of the University of Vienna, Austria, claims to have discovered a method by which milk, treated by radio waves of short length, can be kept sweet for from three to four weeks! Health authorities in Germany now are testing the process.
How to Build One That Will Add Vastly to Your Pleasure in Woodworking and Model Making—The Lumber and Joints to Use—Full
IT IS all right to do model making or other light work on the kitchen table or at a makeshift bench, but sooner - or later every amateur mechanic feels the need for a real workbench. If you have no bench, why not take the time right now to make one, and then gain back the time over and over again through the increased speed with which you are able to work?
Three Brilliant Designs for Lights in the New Mode—Cost Is Low, and Construction Easy
LAMPS are such vital, intimate accessories in the modern home, it is but natural that they should be touched by the magic wand of modernistic art. Lighting fixtures designed in the modern manner have been much in evidence in recent furniture exhibitions and have been generally acclaimed.
That Will Inclose in Glass and Keep Safe from Dnst and Accidental Damage the Rigging and Other Fragile Parts
E. A. McCann
IF YOU have built a small ship model with much fine detail and delicate rigging, you will undoubtedly wish to place it in a glass case to protect it from the ravages of the feather duster, the vacuum cleaner, and other implements of house cleaning.
Stippled, Polychromed, and Flat Finishes—Color Schemes—How to Use Sprayers—And Simple Hints to Increase Heating Efficiency
AFTER remaining for years unchanged as an object of often garish and commonplace appearance, the radiator now is yielding to the artist’s touch, like all our household furnishings. Radiator covers to protect walls and curtains from dust, as well as to beautify the appearance of the heating coils, have come into common use.
Device Invented for Refueling In the Air—Flying Post Offices Will Sort Mail—Record Smashed For Barrel Rolls—Safer Plane Built—Flyer Can Carry Hangar
BETWEEN New York and San Francisco on the transcontinental air mail route, the I first “air post office” will shortly be put in service, Postmaster General New announces. Postal clerks will ride with the mail and sort it in the air. The new service, which may later be extended to others of the twentythree mail routes now in operation, is made necessary by the increased volume of air mail following the recent reduction of rates.
AHANGAR you can carry in your plane’s cockpit, and unroll and set up wherever you land, is the latest novelty to be offered flyers. It shelters a plane completely, giving adequate additional space for working. When taken down, the fabric shelter rolls into a compact bundle with its stakes, guys, and collapsible poles, and it weighs only 110 pounds.
AS THIS issue goes to press, the first air-rail passenger service in the United States is scheduled to commence, according to Col. Paul Henderson, Vice-President and General Manager of Transcontinental Air Transport. The air link, between Chicago and Minneapolis and St. Paul, serves passengers arriving in Chicago via the Pennsylvania Railroad's Manhattan Limited and drops them at the twin cities of Minnesota three and a half hours later.
SAWED-OFF airplanes of a new type developed at the California Institute of Technology and illustrated above are said to represent an advance in safety and efficiency. A novel control mechanism permits the whole lower wing to be slid forward or backward in flight to the most favorable “staggered” position for stability at a given speed.
TWISING like a corkscrew through the air, Thursder Johnson, of St. Paul, spun eighty times in the evolution known as the barrel roll the other day to set a world’s record. Previously twenty-six had been the record for this stunt, called the most sickening known to aviation, in which the plane continues its forward motion while spinning like a screw.
COTTON cloth and canvas, impregnated with resin, are two of the latest materials of which airplane propellers have been made. In efforts to develop a nonbreakable propeller that would have a certain very desirable elasticity and resist corrosion and moisture, the cotton fabric was placed in layers until the thickness desired was obtained, and then molded into blocks under tremendous pressure and heat.
VARIETY in plenty awaits the prospective airplane purchaser, according to a recent survey of eighty-nine types of commercial and private planes made by sixty-one manufacturers. For a sum that varies from $695 to $60,000, it is possible to buy a plane with a capacity of from one to fourteen occupants.
ONCE there was a joke about a scared darky automobile mechanic who declined to fly for fear he might have to “get out and get under” to repair his machine in the air. Now that remarkable feat has been performed by Paul Charles, airplane pilot of Gettysburg, Pa.
AN AIR letter that traveled around the globe to its starting point in seventy-one days is said by its sender, Osborne B. Bond of New York City, to have set a new record despite mishaps which delayed it along the way. Only a part of its journey—between New York, where it was first mailed and Seattle, and between Basrah and Cairo, Egypt, was by. airplane.
Reliability Tour, 6,300Miles, Is Completed by 24 Planes
LIKE a covey of birds returning home to roost, twenty-four of the twenty-five airplanes that started the 1928 reliability tour for the Edsel Ford trophy returned to Detroit the other day, after an unparalleled record of motor efficiency and maintained schedule. A thirty-two-leg course had taken them over a route of 6,300 miles, twice over the Rockies, and covering seventeen states; with them flew the referee, Ray Collins, of Detroit, in an Army Air Corps scout plane.
THE Navy believes that an officer who knows how to fly is a better officer. That is the interpretation of a recent order that, since all officers cannot attend flying schools, their private flying is to be encouraged. When questions of promotion and retirement arise consideration will be given to men who have taken up flying independently.
DID you ever wonder how a close-up movie scene of a dancing couple was made? Here is the secret, as practiced at one large studio. The whole camera and tripod are mounted on a movable platform, drawn across the floor by a harness that encircles the dancers.
"WTHEELBARROW forts" form the latest aid in fighting criminals. London policemen have just tried out the idea. Full length bullet-proof shields are mounted, as shown below, on little-wheeled trucks that can be run into position whenever a gang of thugs is fighting at bay.
THIS magazine is always more than glad to answer readers’ questions regarding any subject within its field and to supply names and addresses of manufacturers of articles described in its columns. Inclose stamped,self-addressed envelope for the reply and write to Information Department, POPULAR SCIENCE MONTHLY, 250 Fourth Avenue, New York City.
WHAT color coal will you burn this winter? Blue coal is the novelty introduced by one great concern, of Buffalo and Rochester, N. Y. In the last of several washes the coal receives on its way to the consumer, it is treated with a blue dye to make it more attractive. The dye costs only three or four cents a ton, and does not affect the heating value.
Big Mail Carrying Torpedoes Would Go 225 Miles Hourly
STREAMLINED mail-carrying torpedoes, whizzing along on eight rubber-tired wheels at 225 miles an hour on a track thirty-five feet above the ground—this is the plan presented by two French engineers. Augustin Talon and L. Hirschauer. who estimate that such machines could attain their maximum speed in sixty seconds.
WHEN you are stranded on the road with tire trouble, late at night, and no flashlight is at hand, a makeshift trouble light is easily provided. Scrape up a small pile of sand, pour about a cupful of gasoline on it, and ignite. It will burn fifteen or twenty minutes.
THE “nerve center” from which pilots flying over American air mail and transport lines get their information about weather and other matters important to their safety is shown in the photograph above. From a station on the twelfth floor of the Department of Commerce Building in Washington, D. C., the -information is transmitted by telegraph, as seen in the picture, to the powerful Arlington Naval radio broadcasting station.
YOU can write in electric lights with a novel changeable electric sign. By fitting the lamp sockets into perforations in a vulcanized panel, anyone can spell out messages without having had any previous experience in hand lettering. The new display panel is recommended by its makers for use in stores*to mark different counters and to announce special bargains, as well as for other purposes where an illuminated sign is desirable.
ALL along the Atlantic coast of New Jersey, ocean waves have been tearing away the beach for years. Authorities of popular seaside resorts have taken counsel, and now, at Alienhurst, N. J., they are installing a unique sort of breakwater to tame the waves—an offshore pipe that fills the surrounding water with compressed air bubbles, through a system devised by Philip Brasher, Princeton, N. J., engineer.
DID you ever wonder how “Information” found the telephone number you requested in those few seconds before her reply? The photograph at the right shows how it’s done at Cleveland's new information bureau, where the names, addresses, and telephone numbers of thousands of subscribers, printed on cards, are kept in rotary files that can instantly be whirled to the proper index mark.
Attention, Inventors! Here's What the World Is Crying For
THE new annual edition of “What’s Wanted,” an English book suggesting needed inventions, has just been published by the Institute of Patentees. Among the new wants it lists are: A pencil that makes a mark as black as ink. An indicator to denote when an iron is hot enough to use without scorching.
IF IT rains, get inside part of your hand bag and keep dry! That is the advice of the English inventor of a hand bag with a raincoat attached—and certainly showers should have no terrors for the owner of this device. When not in use, the coat folds up and forms the outer covering of the bag.
YELLOWED piano keys may be restored to their original whiteness, science has learned, with a solution made by pouring one ounce of nitric acid, slowly, into twelve ounces of soft water. Do not reverse this; for nitric acid is destructive to skin and clothing and may safely be handled only in this way, to avoid boiling and spattering.
A VERITABLE merry-go-round for parked cars Is the endless carrier devised by Joseph I). Bell, of San Francisco, to conserve storage space in small garages. It also makes it easy for a motorist to obtain instant access to his car. Six movable platforms, each with space for one automobile, are rotated by the touch of an electric button.
A SPECIALLY built automobile that plunges in and swims across streams and lakes is part of the equipment of an expedition sent to study the Aleutian Islands. These islands, extending 1200 miles into the Pacific from the coast of Alaska, contain active volcanoes about which little is known.
ONE of the oddest minerals in the world is Gilsonite, a brilliant black asphaltic substance found only in Utah that is in demand all over the world for use in manufacturing paint, varnish, ink, and telephone mouthpieces. It was discovered in 1862; but it was not successfully marketed until 1904.
Boat Run by Air Propeller Works on Plane s Principle
ATINY motor boat run by an electric fan—or what appears to be one at first sight—has appeared in Germany. The Canadian Seagull. as it is called, has shown surprising speed. The propeller, mounted on the rear, is inclosed to prevent injury to passengers and lest clothing become entangled in its whirling blades.
FOR the first time. helium gas, used instead of inflammable hydrogen gas to float balloons and dirigibles, has been placed on the open market. Formerly the gov eminent controlled this country's supply. which came almost exelusively from its plant at Fort Worth, Texas; but with the opening of a new plant to extract helium from natural gas at Amarillo, Texas. officials of the U. S. Bureau of Mines announce that. abundant helium at moderate cost is now assured not only for the War and Navy Departments, but for the whole country generally.
Test your knowledge with these questions, chosen from hundreds asked by readers. Correct answers are on page 161. Where Mere seashells used for money? What are the nomads? Where do natives regularly cook their food in hot springs? On Mhat island are human beings forbidden either.
WorldWide Huntfor Radium Planned by Carnegie Expert
WORLD-WIDE search for new sources of radium, probably the world's costliest substance, is to be made by Dr. Charles S. Piggot, of the Geophysical Laboratory of the Carnegie Institution at Washington, D. C., he recently told the Washington Academy of Science.
THAT the shape of the bones in a man's finger may show that he is a carpenter is one of the novel conclusions of a cent German investigation reminiscent of the fictional detective feats of Sherlock Holmes. Under the X-ray, experts found, peculiarities in the shape of a workman’s fingers revealed that they had long used a plane or similar wood-working tool.
THIS device was developed by a Cleveland inventor for the benefit of motorists who have to squirm about and crane their necks to see overhead traffic lights. It consists of a small lens which is attached to the windshield in front of the driver.
WHEN Charles Callan, accused of robbing the poor box of a New York church not long ago, denied the charge, he was confronted with a photograph that find caught him in the very act. He remembered, then, a flash of light near the church’s altar rail that had startled him and caused him to flee—not fast enough, however, to escape the arm of the law and a swift conviction based on the photograph's evidence.
FRESH air is brought up through the legs of chairs into the auditorium of the Congressional Library. at Washington, in a new ventilating system. Additional air to keep the millions of books free from brittleness or musty odors is washed with water and oil, to clean and humidify it, and blown through the shelves.
THE automobile instead of the driver does the work in using this new jack, consisting of a runway and a supporting table. A steel arm from the runway sets the supporting table in position to receive the axle when the car is run up and lowered to the table. To lower the car to the ground again, all that is necessary is to give a sharp jerk on the chain attached to the trip, which collapses the supporting table.
A NEW varnish that dries thoroughly in four hours after it has been applied enables house painters and others to apply two coats in a single working day. Formerly a single coat required twenty-four hours to harden properly.
YOUR car is most likely to skid on wet pavements just after the rain has started. The first drops unite with the dust to form a slippery film. A heavy downpour washes this away. The most dangerous of all skids is the front-wheel skid, but, fortunately, this does not happen very often.
TWO Los Angeles boys. Oliver W.Young and Ralph E. Olson, have organized a miniature airplane fact ory in that city which is doing a thriving business. Besides their plant, they have their own “flying field“ where “test pilots“ try out the glistening machines as they come from the factory.
THIS polite automaton, which has been placed in several parks in Berlin by a German newspaper, says “Thank you“ when it delivers a paper after a coin has been dropped in the slot. A $25,000,000 company has recently been formed in the United States to build similar automatons which are to be installed in cigar stores throughout the country.
ASTRANGE story of the near extinction of a tree and its later revival is told by Dr. Edgar T. Wherry, of the U. S. Department of Agriculture, who is searching for a mate for it in order to write the last chapter of its history. As long ago as 1765, John Bartram, early American botanist, discovered a small patch of the ornamental trees called Franklinia, after Benjamin Franklin, growing wild near Fort Barrington, Ga. Shortly after, a number were transplanted to Philadelphia.
BOUNCING balls of steel go mathematicians one better in a counting device recently exhibited in London by the Royal Society and used in telephone traffic estimates. Hitherto it has been a laborious and time-wasting process to calculate in advance the number of telephone calls and their routing that might be expected by a new telephone exchange.
BUDDY, an Army horse stationed at Governor’s Island, New York, is shown wearing the latest mask designed to protect war horses and mules during gas attacks. The bag of the mask fits tightly over the nostrils of the animal and is held in place by straps buckled over its head.
THE strange machine at the right is a combination eight-day electric clock, powerful microscope, and moving picture camera. Set it and leave it alone for eight days and then you can take out a film that shows the development of a flower! Besides filming the growth of plants, the new machine is expected to catch the life history of germs and even to show on a strip of film the development of a chicken within the egg.
WHEN a heart beats, contractions sweep over it in successive waves, from top to bottom. This was shown in slow motion pictures recently made of the heartbeats of an anesthetized animal by Dr. L. B. Arey, Professor of Anatomy at Northwestern University Medical School, Chicago.
FLAMES leap outward from the surface of the sun at a rate of 20,000 miles a minute and sometimes reach a height of half a million miles, according to Dr. Ferdinand Ellerman, of Mt. Wilson Observatory, in California. When these “prominences” were first noted, during a complete eclipse, early astronomers were divided as to whether they belonged to the sun or the moon.
A 2,400-HORSEPOWER speed boat that will be able to cross the Atlantic from Brest, France, to New York in fifty hours, according to the claims of its designer and builder, is being constructed by Ettore Bugatti in his automobile plant at Molsheim, Alsace.
NEW bits of comment gleaned from the movie world discuss the latest aspect of “talking movies,” whose threat to invade a field long reserved for the silent drama was described last month in POPULAR SCIENCE MONTHLY. Amateur talking movies in the home are a possibility frequently mentioned
A SENSITIVE new colorimeter, devised by Dorothy Nickerson, of the U. S. Department of Agriculture, instantly grades hay, cotton, and other materials according to their color and does away with the necessity of more complicated tests. The field of the eyepiece of the instrument has two halves.
MEN behave like vegetables for a third of their lives, according to Dr. II. M. Johnson, psychologist at the University of Pittsburgh. When men are asleep, he says, they do nothing, know nothing, enjoy nothing. They are in a similar state to that of vegetables.
NO LONGER is it necessary to mutilate license plates to make them fit the brackets on your car, according to Ray M. Hudson, of the Department of Commerce's commercial standards division. Plates in every state now conform to standard bracket slots proposed by the Society of Automotive Engineers.
A RECENT survey at Washington, D.C., reported in a bulletin of theU. S. Bureau of Standards showed that locked bumpers were a more serious cause of traffic tie-ups than any other single trouble; and the first step toward a remedy has been taken with the drafting of a uniform code for motor coaches providing for a standard bumper height so that in the event of minor collision the bumpers will meet face to face.
OCEAN liners, without propellers or rudders, pumped through the water at the rate of 100 miles an hour, are the plan of Virgil C. Anderson, of San Francisco. Anderson, who was in the submarine service during the war, believes that two twenty-four-inch pistons with a six-foot stroke, working in cylindrical pipes, drawing in water and expelling it under high pressure from the rear, would drive the vessel across the Atlantic in less than three days.
HUGE shipping boxes that transform a railroad flat car into a sectional box car have recently been tried in Great Britain to meet the growing competition of automobile trucks as freight carriers. They dispense entirely with the tedious process of loading and unloading a standard box car.
THE remarkable machine at the right, which turns out as much Avork in one minute as a human clerk can do in six hours, will help Uncle Sam tabulate the census of 1930. It is shown being tested by an employee of the Census office in Washington, D. C. The machine puts down sixty facts on cards by punching holes in them to indicate the answers to questions.
SPEEDING cars are stopped instantly at the will of the driver through “wheel chocks,” new substitutes for automobile brakes, according to claims of the inventor, Pasquale Strano, of Elizabeth, N. J. They are said to have brought a light car moving tiventy miles an hour to a halt in less than fiAre feet without damage to the automobile or shock to the driver.
“Televox” Acquires Voice; Mechanical Man Uses Phone
NOW “Mr. Televox,” the East Pittsburgh, Pa., automaton created by Roy J. Wensley, Westinghouse engineer, has a deep bass voice. A mechanical man Avith electric coils for muscles and a newly-added strip of “talking moA’ie” film for lungs, he is able to acknowledge a call A’ocally and even to put one through on his oAvn account if necessary.
EVEN the U. S. Patent Office plays a part in the presidential campaign. It has been swamped by applications of inventors and manufacturers of advertising specialties to boost one candidate or another. New designs for buttons, banners, and auto windshield stickers, even for cap bands are among the many novelties received.
AMYSTERY more than thirty centuries old was solved recently in England with the help of modern chemistry. For fifty years, an ancient Egyptian manuscript had lain in the British Museum unread. The leather roll had become so brittle that no one dared open it.
Film Showing Color Shades Here for Amateur's Camera
AN IMPROVED film for the use of amateur photographers has recently been put upon the market by a British concern. It is known as panchromatic, or equally color-sensitive film. It should not be confused with the new Eastman color movie film, described elsewhere in this issue.
THE life of silk depends upon how it is washed, says the Bureau of Home Economics of the Department of Agriculture. Wash silk garments in lukewarm water, never in hot. Do not rub hard or twist the fabric. Rinse thoroughly in water the same temperature as' that of the washing and remove the water by squeezing and patting the silk between dry towels. Never dry silk in the sun.
CREATING a cloud of poison smoke. a machine guided by a driver wearing a gas mask moves across a cotton field, exterminating the boll weevils as it goes. Poison dust is fed from a hopper into a small fire box from which a fan forces the heavy, gaseous smoke into a tentlike inclosure that prevents its being dissipated before it reaches the ground.
TILES which absoro sound have been developed by engineers of a Chicago laboratory. They are made of metal in the form of trays, sixteen inched square, perforated so that sound passes through them just as it does through a screen window. The trays are packed with a feltlike, sound-absorbing material which is said to consume seventy percent of the noise that reaches it through the perforations.
“MECHANICAL interne” that is governed by the breathing of the patient has been invented by a professor at the University of Maryland to administer anesthetic at an operation. There are, he says, three distinct stages through which every person goes in receiving an anesthetic, the “irritative,” the “fighting” and the “completely unconscious.” In each stage the breathing differs.
A METAL gets tired and needs a rest the same as does an animal, says Prof. J. B. Kommers, expert on metal fatigue at the University of Wisconsin. When an axle breaks or an automobile wheel drops off without apparent cause, the reason usually is that the metal was fatigued and needed a rest and didn't get it.
IT TOOK a crew of fifty men just thirty-six working days to erect the steel framework of a twenty-five-story Chicago building, setting a new speed record for construction jobs of that great size. As the building rose to its final story, a fifteen-ton derrick helped swing the steel columns and beams into place.
AUTOMOBILE motor exhausts should be on top of cars instead of near the ground, according to Dr. Louis I. Harris, formerly Health Commissioner of New York City, who has suggested the change to several manufacturers as a means of reducing the amount of carbon monoxide breathed by city dwellers.
OUTFITTED going yacht, like this a motor luxurious vehicle, seacalled a “Flatavan,” built by an English engineer for an Easton, Maryland, sportsman, who w ill make a hunting trip to the Rockies in it, can speed along at forty-five miles an hour. The van has four compartments, a lavatory with a showier bath, a saloon, a kitchen, and a driving compartment.
IN THE “Pullman-sedan” seen below a few simple motions will adjust the front and rear seats to provide a comfortable bed for the night. Tourists, says the inventor, may park anywhere nightfall finds them and sleep as restfully as they would in a hotel.
A DUCK valued at $5,000 was recently exhibited at the Field Museum of Natural History in Chicago. It was a specimen of the extinct Labrador duck, said to be rarer than the famous extinct great auk. Only 45 specimens exist in the whole world, according to Dr. Wilfred Osgood, curator of zoology at the museum.
THE world's wettest farm lies on the gulf of San Bias in Eastern Panama. Known as San Bias Farm, it is the headquarters for a large banana plantation. In three months, the rainfall there totaled 137.12 inches—three times as much as is usually recorded in Washington, D. C., in a year.
SENDING shorthand messages by wire is the latest application of the telephotograph. A picture, accompanied by a hundred-word message written in shorthand explaining it, was recently sent from the telephotographic station of the American Telephone and Telegraph Company in New York City to Los Angeles in about seven minutes.
AN ASSASSIN insect in the Dutch East Indies that poisons and then stabs its victims has been observed by the British entomologist, W. E. China. It is a distant relative of the cicadas and expells a poison fluid that attracts a certain species of black ant.
THIS magazine is always very glad to answer readers' questions regarding subjects within its field, and to supply names of manufacturers of articles mentioned in its columns. Inclose stamped, self-addressed envelope and write to Information Department, POPULAR SCIENCE MONTHLY, 250 Fourth Avenue, New York City.
NINETY percent of the height growth of trees in the latitude of Pennsylvania is attained during forty days in spring and early summer, according to an investigation reported by the American Tree Association. This contradicts the belief, held for many years, that trees grow steadily from the time they put out their leaves in the spring until the frost comes in the fall.
NOW devotees of the open air can take a sun bath any time in complete privacy whether they are in a city's midst or touring along an open road. A new English automobile. outwardly rescembling a standard sedan, is equipped with a demountable top that can be rolled back completely to admit the sun.
OWNERS of cars equipped with this novel device, invented by a French mechanic, need not get out and walk around to the back to see if the tail-light is on. The tiny indicating lamp fits on the dashboard and is dark as long as the tail-light is functioning properly.
THE "diary" of a glacier, covering seventeen years. has recently been Made public by Prof. R. T. Chaniberlin, of the University of Chicago. Lines scratched by two needles on a clock disk kept the record and proved a theory of glacial movement advanced thirty years ago by Prof.
THIS sturdy little American tractor at work on Prince's Pier. Melbourne. Australia. has taken the place of horses which have been used for years to shunt railway cars about the tracks leading to and from the ships. The trac tor pulls the cars behind it by a hook attached to the back or pushes them before it with a heavy steel bumper braced in front of the radiator.
VERY year $100 ,000, 000 worth of property goes up in flames in the United States because matches burn too long. That is the conclusioii drawn from a recent series of experiments carried on in Washington, D. C., by the Bureau of Standards. The average length of time required to light a pipe or cigarette was found to be ten seeonds.
THE highest dam in the world is being constructed in the Owyhee River in eastern Oregon, near the Idaho line. under the direction of the Bureau of Reclamation, Department of the Interior. Nearly half a million cubic yards of concrete will be used by the Seattle, Washington, contractors.
foul tip crashes into the new catcher's mask, seen at the left. the player is completely protected. At the same time, the elimination of vertical wires in the construction insures him an unobstructed view of all parts of the field. This improved mask made its appearance when "Bubbles" Hargrave.
BEFORE good roads and the radio wipe out dialects in the United States, Columbia University is going to record permanently on phonograph records the characteristic speech of different sections of the country. The university has set aside $500 for this purpose.
SIXTY-ONE years ago. a Boston newspaper published this editorial : “A man about 40 years of age. giving the name of Joshua Coppersmith, has been arrested in New York for attempting to extort funds from ignorant and superstitious people by exhibiting a device which he says will carry the human voice any distance over metallic wires so that it will be heard by the listener at the other end.
Gus and Joe Hire a Wizard Who Doesn't Bat an Eye at a Dead Battery or Broken Steering Arm
"I WONDER how 'Spare Parts' Harbison made out with that queer little mechanic you talked him into taking on his automobile trip?" Joe Clark observed. Must have worked so well that `Spare Parts' extended his trip to cover a lot more territory." replied Gus, who was Joe's partner in the Model Garage. "I wish they'd come back.
Tank Measures Gasoline by the Mile—Radiator Thawed by Steam—Emergency Grease Gun—A Runway Over a Curbstone
THE simple auxiliary gasoline tank shown in Fig. 1 will prove very useful to the experimentally inclined motorist. With one of these tanks on your car you can determine gasoline consumption in miles per gallon with the greatest ease. You can quickly determine the most economical speed at which to run your car either on the hills or on the level.
IF YOUR radiator freezes while you arc driving, a simple way to thaw it, as shown in Fig. 2, is to attach a short length of rubber hose to the overflow pipe from which the steam is flowing and squirt the steam through the fins of the radiator. Start at the top and work downward.
FRED J. SEVERS, of St. Louis, wins this month’s $10 prize with his suggestion for a gasoline gage (Fig. 1). POPULAR SCIENCE MONTHLY awards $10 each month, in addition to regular space rates, to the reader sending in the most valuable suggestion for motorists. Other published contributions are paid for at regular rates.
ONE of the messiest jobs about an automobile is filling the differential housing with grease if you have no grease gun. To avoid this difficulty, make up a cone from several thicknesses of newspaper, fill it with grease, and insert the end of the cone in the filler hole in the rear end housing.
IN CASES where it is desired to have a curb on the sidewalk opposite the driveway to your garage, some provision must be made to eliminate the constant pounding your tires will get if they are forced to climb the curb every time you drive the car in.
WHAT to do with safety razor blades—that eternal question—may be answered in the home by adopting the method used on Pullman cars. Cut a hole through the plaster of the bathroom wall and place a piece of the slotted metal over it, as shown in Fig. 1.
How to Build More Speed and Distance into Your Miniature Aircraft—Bamboo, Covering Materials, Propellers, Fittings
Blueprints That Make Model Building Easy
Removing Floor Finishes
J. DANNER BUNCH
AVISON F. KOCH
MANY enthusiastic constructors of model airplanes are hampered by a lack of facilities. They do not find difficulty in obtaining the few tools needed, but they often discover that it is no easy task to buy suitable materials. Every model builder should get the catalog of at least one wellknown model supply house and familiarize himself with standard materials and fittings.
Once You Know How to Tame Music Wire and Other Stubborn Stock and Can Make Mandrels and Tools
H. L. WHEELER
IT WAS a proud moment for Jack Blinds when he stepped out as a journeyman machinist. Decked out in his brand-new overalls and quite confident of his own mechanical knowledge. acquired in four hard years of apprenticeship at the railroad shops in his home town, he presented himself to Ed Wilkins, foreman of the general jobbing shop in which he was to work.
Adapting a Lathe for Production Work—Two Ingenious Milling Kinks
Old Bill Says—
R. H. KASPER
WE HAD an order recently for a quantity of “spuds” as shown in Fig. 4 above. The shop’s equipment included nothing more suitable for the work than an engine lathe, but we developed tooling equipment that made the job very simple. And the same principle can be applied to other lathe work of similar character.
EVEN in this day of public and circulating libraries, all of us have a few choice volumes and need a convenient place to keep them. The bookcase illustrated at the right is large enough to hold many books and has, in addition, a rack for current magazines.
F. N. V anderwalker Explains How Rough Surfaces Can Be Painted Smoothly
AFTER sandpapering some wooden surfaces as much as possible, you often will still find, especially on the poorer grades of lumber, certain rough areas that are too deep to be made smooth. These are usually the areas around knots where the end wood fibers are short and run in various directions.
How to Build atLow Cost a Fireproof Strong Box of Metal-Lined Concrete
NEXT box in or security a good to safe a safety for keeping deposit valuable papers is a fireproof vault like the one illustrated. It is often necessary for the writer to take valuable papers to his summer home, which is some distance from any bank or trust company.
MANY all veneered have the furniture mistaken is idea modern. that Veneering was done by Chippendale, one of the first of the famous old furniture masters. He did not veneer his furniture to deceive the purchaser and make him believe it to be made of solid wood, but because it was possible to obtain more beautiful grain and a wider range of figures in veneer.
AN EFFICIENT, attractive lighter for your smoking stand may be made by providing a pocket lighter with a suitable base. The one illustrated, which includes an ash tray, is but a suggestion of the many designs that may be worked out. Its cost for materials for the mounting was twenty-five cents.
MOTORS taken from old Ford cars are frequently used as power plants by farmers. The main objection to this type of motor is its irregular speed under various conditions, but this can be over come by adding a governor. Obtain a governor of the flywheel type (A, Fig. 2) from a discarded gas engine; usually one can be picked up at a junk dealer's yard.
BROKEN garden furniture, sundials. bird baths and the like, if made of concrete, may be mended, contrary to common belief, so as to make the line of the break even stronger than when the piece was whole. The fragments should be soaked in water for at least twelve hours.
OUR blueprints can be obtained for 25 cents a sheet. In some cases there are two or three sheets to one subject. The blueprints are complete in themselves, but if you wish the corresponding back issue of the magazine in which the project was described in detail, it can be had for 25 cents additional so long as copies are available.
TWO first prizes and the grand prize in a Boy Scout handicraft exhibition at Galesburg. 111., were won by 14-year-old Glade Wilcox, with the models illustrated. One is a 3-ft. flying scale model of the Spirit of St. Louis; the other is a model of the Sovereign of the Seas, a famous clipper ship.
BY THE method illustrated, shelving can be installed in the closets of a rented apartment or house without defacing the walls. The shelves can be readily removed at any time. Two supports are assembled as shown with corrugated fasteners, which can be obtained at any hardware store.
ONE of the simplest yet most valuable chemical tests which the handy man or scientifically minded boy can perform at home is to determine if there is sulphur in gasoline. Sulphur in gas burns in the motor to sulphuric acid vapor, which corrodes and pits the valves and other accessible surfaces.
WITH the starting of the house furnace in the fall comes the ash dust nuisance. Every time the ashes are removed, an impalpable and penetrating white cloud spreads through the cellar and often enters by devious cracks into the living-rooms above.
SUBURBANITES and others who have a few chickens and keep them locked up at night usually find it inconvenient to get out of bed at daybreak to let them out of the chicken house. The chickens, however, can let themselves out if a door or window is fitted with the automatic release illustrated.
THOSE who articles who in have this followed series have, the previI am sure, acquired a certain measure of skill and confidence with wood-turning tools by this time. They will find faceplate turning, the next phase of the work, not more difficult than spindle turning; and no set of exercises need be mastered before real work can be attempted.
THE paint spraying outfit shown in the accompanying illustration cost less than $10 to construct. With it I have done many lacquering jobs, including the finishing of a breakfast set. The 1/6 h.-p. motor is from a washing machine and cost $5 secondhand; it serves for other purposes besides operating the spray.
WHEN many notes have to be taken from a book which will not lie flat unless held down or weighted, the volume can be held open by the simple expedient illustrated. Two paper clips are fastened to the leaves on opposite sides and a pencil is run through them.
ANCIENT looking treasure or pirate chests, which have become so popular for purely decorative purposes, make a novel and excellent type of cabinet for sheltering homemade radio sets. They are of distinctive appearance and allow unusual ease of access to the set itself, especially if built according to some such plan as that illustrated below.
ANYONE who has ever attempted to letter small cylindrical work neatly, knows that it is difficult. Otherwise well-made parts are often deficient in this one respect. As a very slight displacement of a single letter is enough to spoil the appearance of a piece, the chances are all against the man who tries to do such work by ordinary means.
PRECISION gage blocks can be saved from wear and their accuracy preserved for a longer time if they are supplemented by a gage of the type illustrated. It is a compact and convenient auxiliary to a set of costly gage blocks, and the toolmaker will find many uses for it.
OIL holes into babbitted boxes can be provided, without drilling if tapered wooden plugs are inserted before the babbitt is poured. The plug should have a flat end and be in contact with the babbitting mandrel. Where the boxes are solid, common yellow laundry soap can be rubbed on the shaft before the babbitt is poured.
IN THE sleeve puller illustrated, a plunger engages the grease hole in split sleeves of a type commonly used with certain roller bearings. The plunger has a collar for the spring to push against. A pull rod is provided for use with a crossbar of some kind, which rests against the housing.—(G. A. L.
THREE hundred forged nickel-steel shafts, 2 1/2 in. in diameter and 5 ft. long, had to be cut to length, faced and centered, preparatory to a turning operation which required first-class workmanship and high production. The only machine available that would take them through the spindle was an old 24-in.
SOME unusual problems were presented in the machining of a cast-iron roll forming part of a special machine, and the ingenious methods applied by the machinist may be of interest and help to other mechanics. When delivered to the machine shop, the casting for the roll was found to have very little stock for finishing, and the hole was not true with the outside.
IN MAKING bushings for drill jigs or similar work, the combined plug gage and arbor illustrated will save much time. It should be made of tool steel, hardened, or of machine steel, pack hardened.—H. J. C.
LACQUER brushes should be wiped out as dry as possible after use, then shaped up and allowed to dry. When ready to vise them again, soak them in lacquer thinner. If one brush is to be used in several colors, it must be thoroughly cleaned when colors are changed.
BY VIRTUE of its saucer shape and lightness, this tissue paper toy parachute will float a considerable distance in a light breeze when released from a second-story window. A square of any fairly tough tissue paper will serve. Make it as large as your paper will allow, or paste four squares together.
AFTER expending much effort in building a piece of furniture or other cabinetwork and applying several coats of varnish, many home workers make the mistake of leaving the finish in a high gloss. The piece has a certain crude, glaring look, and if there are any imperfections whatever, each one seems to be magnified.
HINGEWS, locks and other hardware for use in the bathroom, laundry, kitchen, and other rooms where there is considerable condensation of moisture, should never be of iron or steel unless well protected against rust by paint, enamel, or galvanic coating. Plated ware will seldom stand up in such places unless the plate is exceptionally heavy.
IF A lid support is fitted by the trial and error method, it is quite certain that the lid where plate A is attached, or the desk at screw B, or both, will be marred during the process. This particular type of lid support, nevertheless, can be more easily fitted than some other styles and it may be used at either the right or the left end of the lid.
BOOKS placed between book ends or in a rack made as illustrated seem to be standing without visible support. That is because the end volumes are dummies glued and screwed to the base pieces. Choose two attractive old books, preferably leather bound, of about the same size—there is always a large choice of such volumes at a secondhand book store—and discard everything but the covers.
ONE end of my cellar is completely outfitted with shelves divided into compartments. They were erected in less than half an hour's time and at practically no cost, because they consist of orange crates stacked one on top of the other and braced with narrow boards on each end of each tier of boxes.