YOU’RE in Wall Street...tell me something good. I’ve got $500 and I want to run it up to around $1,500 within the next two or three months. What’ll I buy?” In such words was the Financial Editor of POPULAR SCIENCE MONTHLY recently greeted. Some readers may see a tincture of humor in this modest ambition to triple a sum of money in three months.
A Letter to the Institute Will Bring Sound Advice on Buying Equipment of the Highest Value
What the Institute Found
The "Cream" of the Market
Where the Tests Are Made
Price Is a Factor
Use the Institute Service
F. G. PRYOR
ADVICE is cheap enough and there are always plenty of people ready to offer it, as any buyer knows. The remarkable part is that so many of these people can say very definitely and conclusively just which make of product is “the best.” As a rule, the more limited their knowledge, the more positive they can be in their assertions.
"WHY do you and others persist in using the awkward and confusing word ‘noninflammable’? Bearded etymologists may produce all sorts of justifications for this word, but sensible and practical people usually avoid it because its meaning is so cloudy.
For months, now, political and industrial leaders and the newspapers have been talking excitedly about “power” and “super-power.” Seldom, however, has anyone explained exactly how or why the discussion is a matter of public concern. This article tells in simple terms why every family and every factory has a vital interest in future sources of electric power, which already has entered 19,000,000 homes, has given to every factory worker the equivalent of 55 helpers, and serves three fifths of the American people.
GROVER C. MUELLER
"THE North Pole could be made into a summer resort if sufficient power were available.” So declared the Earl of Birkenhead, who is one of England’s greatest statesmen and a leading figure in the electric power industry, on a recent visit to the United States.
FOG costs the world millions of dollars a year in transportation delays and accidents. It is the arch foe of flyers and mariners. A bucket of water in the form of fog can tie up the port of New York or London, and can send airplane pilots to their death. This article describes important gains in the first large-scale attempt of science to conquer the worst of man’s weather enemies.
EDWIN W. TEALE
FLYING “blind,” in an airplane cockpit so covered by a hood that he could see only the glowing dials of the instrument board, Lieut. James Doolittle,a crack Army pilot, took off at Mitchel Field, New York, the other day, flew seventeen miles, returned to his starting point, and made a perfect landing.
Great Wharves of Steel Reach Out from California Shore to Tap New Deposits in the Bed of the Pacific
Painting a World’s Fair with Light
GEORGE LEE DOWD
OIL from the bottom of the sea is now being pumped into reservoirs from three unique underwater oil fields on the California coast. Huge wharves, a quarter of a mile long, reach out into the Pacific to support the derricks used in plumbing the ocean bottom for petroleum.
The recent flight of the Opel rocket plane lends timely interest to this scientific discussion of proposals to navigate the stratosphere—that bleak layer of thin air far above cloud and storm, where the stars shine as beacons and steady winds promise swift passage over land and sea.
Sunshine in Candy
ALDEN P. ARMAGNAC
ONE mile from its take-off, a frail plane belching a cloud of blue smoke wavered to an uncertain landing near Frankfort-onMain, Germany, a few weeks ago. It grazed the field, scudded across it at sixty miles an hour, spun around, and turned turtle.
“The motions of the solar system since its beginnings are less complicated than the play of a child for a day,” said James McKeen Cattell, presiding over the recent International Congress of Psychology at Yale. Here are presented outstanding experiments and discoveries concerning the riddles of human behavior, as reported to the Congress.
Secrets of Happiness
How to Sleep
Tests of Intelligence
Why People "Get Mad"
Mind - Measuring Machines
Learning from Animals
Psychology Put to Work
Drugs and Moonlight
Man and Woman
CLOSELY following the recent sessions of the International Congress of Psychology at Yale University came the announcement from Washington, D. C., of the first step toward establishing a national center of research in problems of human and animal psychology—the National Institute of Psychology.
Although it was only three years ago that construction began on the first large rivetless steel building in the world—a five-story factory for the Westinghouse Electric and Manufacturing Company at Sharon, Pa.—a recent report of the General Electric Company lists sixty-five buildings, of from one to twelve stories, erected by electric arc-welding alone.
TWENTY dollars a minute is the average sum our Government must spend, year after year, to combat forest fires. Fire can destroy in a week as much timber as lumbering companies can cut in a year. In 1928 forest fire damage totaled $82,934,000.
ON FAR-OFF islands of the Pacific, north of Australia, live savages in conditions as primitive as those of the Stone Age. Many never had seen a white man until visited by the expedition of scientists which obtained these photographs. On a 30,000-mile cruise in the yacht Illyria, owned by Cornelius Crane, of Chicago, this expedition obtained specimens for the Field Museum of Natural History.
HERE are pictured the adventures of two recent expeditions into the Arctic. One was a walrus hunt to obtain specimens for the Field Museum, Chicago. The other was an ill-fated attempt by a Norwegian fishing fleet to break a path through the ice for seal hunters.
Radical Changes in Plane Design — A New Safety Parachute—A Speed Record, Six Miles a Minute
STARTLING departures in airplane design have recently challenged the supremacy of the conventional modern aircraft. Strangest among them, perhaps, is a monoplane which recently took the air at New Castle, Del., and which appears to have been shorn of most of its fuselage.
IN ITS efforts to improve the safety of aerial devices, the Materiel Division of the Army Air Corps has evolved a new type of parachute. In material, size, and principle of operation, the new ’chute is exactly like the old. Instead of a circular mainsail, however, it has a triangular one.
FASTER than any human being ever traveled before, Squadron Leader A. H. Orlebar, British flying ace, recently whizzed over a Calshot, England, flying course of nearly two miles at 368.8 miles an hour—more than six miles a minute! This was the official figure which was averaged with his time on three other laps to obtain the average speed-for the course according to international rules.
"FOUR hours after I enplaned in Buffalo, I deplaned in New York.” Such sentences may be common in conversations of the future. Two new flying words growing out of air transportation are to be included in the latest edition of the New Standard Dictionary.
OVERHEAD control sticks and superchargers for commercial planes are among the novelties revealed by a survey of recent advances in American airplane equipment. The joy stick suspended from above is a feature of a new triengined, six-passenger cabin monoplane.
A GIANT gas bag with a “wire fence” surrounding the basket marks the latest advance in balloon design. The hanging wires are intended to act as a protection against flashes of lightning. This lightning shield was invented by Ward T. van Orman, famous aeronaut, who piloted the new balloon in the Gordon Bennett Trophy Race.
POLAR ice caps would anchor dirigibles in a novel scheme suggested by a German engineer, O. Krell, and inspired by plans tentatively announced for a polar flight, in the near future, by the German airship . Graf Zeppelin. An electrically heated plate-shaped anchor would be used.
WHAT is said to be the first aerial advertising billboard in the world has just been erected near Detroit, Mich. Its tilted sign, visible both to highway travelers and to passengers who fly overhead from the local airport, advertises the merits of a brand of motor gasoline and oils.
TAXI service by airplane to any part of the United States at a proposed rate of twenty cents a mile has just been announced by a New York City concern, which planned to start operation within a few weeks. There are no time-tables, nor fixed rates for a trip. The new line, of which a New York taxicab firm is said to be a principal owner, simply charges a regular mileage rate like that of auto taxicabs in cities. Auto cabs and motor boats will be coordinated with the new service, it is said, in order to pick up the passenger at his doorstep and deliver him exactly where he wants to go. A similar service at a shilling a mile is announced by a British firm that plans to carry “fares” over England in planes just big enough for one passenger and his baggage.
FOLLOWIN G recent demonstrations of a device that enables pilots to pick up and drop air mail without stopping, the first of these devices has been placed in actual service on a Cleveland-Pittsburgh air mail line. It is the invention of Dr. L. S. Adams, of Spokane, Wash.
A DEVICE to disconnect the propeller of an airplane from its shaft so that it may revolve freely is a simple but ingenious invention recently given to his government by Sensaud de Lavaud, French aeronautical engineer. The result is said to be an increase in safety.
Ingenious Measurements of Its Light and Heat Reveal the Old Man’s Pocked Face Powdered with Volcanic Dust
INSTEAD of the silvery moon that poets praise it would be truer to talk about a cindery one. Cinders, the latest scientific researches indicate, are what the moon’s surface is made of; a special kind of cinders like those thrown out of earthly volcanoes and called pumice or volcanic ash.
After 4,000 Hours in the Air, Lindbergh's Former Partner Tells How He Solves the Problems Every Flyer Must Face
THE queerest flying accident I ever had happened in Ohio. I was barnstorming in an old Standard biplane—a ship that was braced with enough wire to bale ten tons of hay. I could test it by letting a pigeon loose between the wings. If the bird found its way out, I knew a wire was gone somewhere!
Diamonds and Salt— Tiny Skyscrapers Built of Atoms
E. E. FREE
THE most famous crystal in the world, the Kohinor diamond, ancient Indian gem of evil and murderous history now safely caged among the crown jewels of England, soon may lose its alluring supremacy. A few weeks ago before the meeting of the American Chemical Society at Minneapolis, Professor J. Willard Hershey, of McPherson College, showed a tiny seed of a gem greater still.
THE ingenious mechanism by which the modern electric pipe organ produces an almost endless variety of sound effects for the movies, ranging from the thunder of a storm at sea to the music of a symphony orchestra or a human voice, is pictured here.
THERE is a story of a medieval prisoner who could see from his cell window nothing but a patch of sky. So he became, as the years dragged on, an expert in clouds and pronounced the weather forecasts for the neighborhood. The tale is scientifically plausible.
TEST your knowledge with these questions, chosen from hundreds asked by our readers. Answers are on page 153. 1. Why do people have to wear eyeglasses? 2. What is astigmatism? 3. Why does an elderly person require two pairs of glasses, one for distance and one for reading?
Indians were still roaming the western plains when the author of this article began his search for the remains of ancient life in America. In sixty years as a fossil hunter he has unearthed more than three hundred prehistoric reptiles, birds, mammals, and fishes. Many of the dinosaur monsters of the museums are trophies of his pick, chisel, and dynamite. Now, at the age of eighty, he tells the unique story of his adventures and discoveries.
CHARLES H. STERNBERG
THE warning whir-r-r of a rattlesnake led to the discovery of bones of the largest prehistoric creature ever found; the accidental stroke of a geologist’s pick into a slab of sandstone disclosed remains of the ancestor of all sea serpents; and the glint of the sun’s rays on a timepolished tooth revealed one of the first of the several forms of the horse.
TO THOSE not aware of the revolution that recently has been upsetting classical psychology, some of the goings-on of scientists who attended the International Psychological Congress at Yale University, described elsewhere in this issue, may seem trivial.
AT THE waterfront in the harbor of Portland, Ore., stands one of the largest plants in the United States for the extraction of oil from copra, the dried meat of coconuts. Large steel freighters tie up at its dock, and their valuable cargoes of copra from Manila, Cebu, or Singapore are unloaded in the shortest possible time through an ingenious system of pneumatic tubes which operate like a vacuum cleaner.
A HOT water bottle designed to protect the tender surface of the user’s skin from burns, even when scalding water is used, has been invented by an Akron, O., manufacturer. This combination of intense heat and painless application is made possible, it is said, by the fact that the outer surface of the bag is studded with nearly 2,000 “thermo-nubs,” little knobs of rubber like those on a rubber massage brush.
A LOCOMOTIVE recently broke an endurance record as remarkable, in its way, as any airplane mark thus far set. When Engine No. 4113, of the St. Louis-San Francisco Railway, rolled into Kansas City, Mo., from Birmingham, Alabama, the other day, it had covered 5,144 miles without having its fire drawn.
AT LAST tramps, hawkers, and other nuisances may be discouraged from annoying the housewife. A Dutch inventor has devised an inexpensive device that will fit any doorbell and cause it to ring only when a penny is dropped into the slot. Visitors, errand boys, and others who have legitimate business at a house will not be out of pocket, however, for they may receive their coin back as soon as the door is opened to them.
USUALLY it is the comfort of the customer that inventors of efficiency devices for stores attempt to safeguard. But one such device that caters to the comfort of the salesman is a new type of seat, designed to eliminate the strain on the backs of shoe salesmen, and recently installed in many shoe shops in Germany.
BANDAGES made of silver, instead of cotton, apparently have the power of healing surgical wounds, according to Dr. P. Maritsch, of Vienna University, Austria. The silver, applied in the form of a thin leaf, he reports, seems to have a marked antiseptic value.
WHERE do the chimney swifts spend the winter after flying south and disappearing in the region of the Gulf of Mexico? How many stops does the scarlet tanager make on its long semiannual flight from Canada to Peru and the nighthawk on its weary trek from the Yukon to the Argentine, and where are their favorite “rest stations”?
GOVERNMENT experts report that twenty percent of the $50,000,000 annual loss in forest fires in the United States is due to the carelessness of smokers, and that most roadside fires are caused by passing motorists who toss out burning cigarette or cigar stubs.
WITH appropriate obsequies that included burning a crape-covered street car and playing Chopin’s funeral march, Vermont recently abandoned the trolley car as a means of transportation. The last line in operation, between Burlington and Essex Junction, a distance of sixteen miles, is now closed, leaving the state without a single trolley track that is used.
CARD tables are saved from being marred by stains from wet drinking glasses and burns from cigarettes by a bridge service set recently placed on the market. The set consists of a drinking glass holder, an ash tray, and a clamp for holding the shuffled deck of cards made in the form of an arrow pointing to the next dealer.
ELEPHANT’S” EARS are not the exclusive property of elephants but are grown also, as leaves, on shrubs related to the calla lily. These huge leaves are a bright green and, when broken, give out a sticky, white milk. They are often more than a yard long; the one being measured below, grown in California, is forty-seven inches long and thirty-one inches wide.
IN THE collection of rare fossils at the Smithsonian Institution, at Washington, D. C., are the petrified skull and bones of a whale which scientists say are at least 3,000,000, and perhaps 8,000,000, years old, probably the most ancient remains of their kind found in America.
ROUND playing cards have recently made their appearance in England. According to the designer of the new pasteboards, their shape facilitates shuffling and dealing. Six sets of spots and numerals are distributed around the edge of each card, so that the suits and numbers may be read easily regardless of the cards’ position in the hand.
“SLAVES” to do their work in the hereafter were buried with the Egyptians of about 2000 B.C. A collection of these substitute workers, or “ushebtis,” were recently placed on exhibition in the Egyptian Hall of the Field Museum of Natural History, in Chicago.
A REMARKABLE new section of the Pan-American Highway, which eventually will connect Alaska and South America, is being opened in Utah. Through the “bad lands” of the southwestern part of the state, the roadway stretches for nearly twenty-five miles, in one place burrowing for a mile and one eighth through the solid rock of a mountain chain.
A RATTLESNAKES’ lair that continues to be inhabited by scores of reptiles, despite the fact that it has been dynamited several times, was found some weeks ago near Wheeler Park, Nevada, by E. Raymond Hall, curator of mammals in the University of California Museum of Vertebrate Zoology.
THE novel spectacle of an outboard motor boat leaping from the water and soaring on wings through the air like a flying fish was witnessed at Auburndale, Fla., the other day. Speeding up the motor of his specially equipped Sea Horse at a terrific rate, Harrison Fraser, one of America’s greatest outboard pilots and speed demons, accomplished that feat.
BY INJECTING into living trees a new fire-resisting mineral “soup,” experts at the College of Forestry at Tharandt, Germany, have produced lumber that is said to be strongly resistant to flames. The fireproofing process consists of feeding a thin solution of chemicals to the tree through holes bored in the trunks close to the ground.
THE great rivers of Africa must be mines abounding in a wealth of ancient ivory, if a new theory explaining the mysterious disappearance of dead elephants, advanced recently by Sir William Gowers, governor of the British colony of Uganda, proves correct.
UNSIGHTLY, torn-up streets, with their prolonged inconvenience to pedestrians and vehicular traffic, are eliminated by a new cable-laving machine recently tried out in Berlin, Germany. The device is designed to lay underground telephone and electric cables and gas and water pipes without tearing up the pavement.
A NEW six-wheeled army reconnaissance truck that needs no antiskid chains to assist it up steep inclines, over sand dunes, and through the roughest terrain was tested recently in the vicinity of London, England, by the British army.
A BOY who falters in reciting Lincoln’s Gettysburg Address and is in the dark as to when to use “who” or “whom” may surpass his smarter brother in constructing a kite or fixing a toy engine. That, in substance, is the conclusion of Dr. Frieda A. Kiefer, a psychologist of Watertown, Mass.
HOW loud should a stage whisper be? A device recently displayed in the Museums of the Peaceful Arts, in New York City, attempts to give an answer by actual tests. A whisper that will carry to the back rows of an empty theater may be much too soft to be heard so far when the theater is full, for the audience acts as a sound-absorbing medium.
SHAVING chemical “whiskers” from cathedral windows by means of ordinary safety razors is the unusual method recently adopted to restore stained glass panes in England. Not long ago, Dr. Alexander Scott, of the British Museum, examined the windows of Wells Cathedral, in Somerset, and found that sulphuric acid fumes from gas lamps used for illumination, combined with dust from the stone with which the building is paved, had encrusted the glass.
INVESTIGATORS of the United States Bureau of Standards, at Washington, D. C., have a new method of reclaiming used oil drained from automobile crank cases.The apparatus consists of a still, a condenser, and a vacuum pump connected to a series of containers in which various grades of oil are separated.
WHEN a small brass tube of radium, valued at $4,000, disappeared from a Los Angeles hospital recently, experts who were put on its trail borrowed an electroscope from the California Institute of Technology to help them find it. The electroscope consists of two hairlike quartz fibers wrapped with platinum in a container under a high pressure and charged with electricity from a dry cell.
A PEOPLE whose language cannot be written live in the Fergansk region of Soviet Russia, a Russian scientist recently reported to the Soviet government. They are the Doungans, who to this day possess no written language, although the art of writing was originated thousands of years ago, surviving examples dating as far back as 4700 B.C.
A “LONE eagle” of the swan family was seen some weeks ago in mid-Atlantic by the passengers and crew of the steamship Homeric. The big snowwhite, orange-beaked bird made a striking picture against the sky as it flew about 100 feet above the sea toward Europe.
THE age-old childhood game of hopscotch can be played indoors with a new toy manufactured by a Lindstrom, Minn., company. The hopscotch toy consists of a base to which is hinged a “springboard” with five holes in a row to accommodate a marble that does the hopping.
AN EARTHQUAKE which caused thousands of dollars damage at Attica, N. Y., recently supplied the town with a much-needed supply of drinking water. It opened some underground streams, which soon filled two reservoirs that had been virtually emptied during the protracted summer drought.
A PORTABLE hay baler that will pick up the hay from the windrows and turn out the bales in the field with a minimum amount of labor has proved practical, according to its designer, Arba Brutus, of Pine Village, Ind. On the hay baler frame he has mounted an old Ford engine, with a governor and an oversize radiator.
NEW proof that sunlight is an electrical phenomenon comes as a result of recently announced determinations of the speed of electromagnetic waves and of the speed of light, declares Dr. Harvey L. Curtis, physicist of the United States Bureau of Standards.
A FLEET of two-seater taxicabs of a new and unusual design is soon, it is reported, to invade the streets of London, England. They are the invention of William Gowan, of Cape Town, South Africa. The novel feature of the new cab is its substitution of a sliding panel for the usual door that opens outwards.
FLOATING serenely on the high waves of the Atlantic between New York and Bermuda, an island of steel is expected soon to provide seagoing airplanes with an ocean landing field. Supported by a veritable forest of air buoys laid out in orderly rows, the world’s first ocean airdrome, 1,200 feet long and 200 feet wide, will rise eighty feet above sea level.
BOBBING up and down like a loosejointed marionette at the end of a string, the user of a new machine for teaching prospective stage dancers to do “splits ” soon acquires proficiency, according to its inventor, proprietor of a Los Angeles school of stage dancing.
AN ODD craft, half airplane, half dirigible, may soon be seen winging its way about the sky, if the invention of John Hodgdon, of Long Beach, Calif., proves to be applicable to an aircraft of practical size. The model which he has constructed consists of a tri-motored monoplane, above which is added a dirigible bag with its own engine and a four-bladed propeller, giving to the craft a total of four motors.
FOSSILIZED animals and plants found in rocks from the site of what is now Chicago give evidence of the existence of a low order of life in that region 600,000,000 years ago, according to Associate Curator Henry W. Nichols, of the Department of Geology at the Field Museum of Natural History, Chicago, Ill.
VIEWED from the air, with the panorama of the city for a background, the new arch bridge at Sydney, Australia, is an impressive sight even in its unfinished condition. When completed it will be the world’s greatest arch bridge, with a central span of 1,650 feet (P.S.M., Jan. ’29, p. 56).
APRIL and May are the “craziest” months in the year, according to Dr. R. Hopmann, of the University of Cologne, Germany. More people lose their mental balance during these two months than in any other equal period, his report says. Statistics on the fluctuations of nervous diseases, which Dr. Hopmann collected, support his idea that in the spring the human mind is less stable than at other times. Police records, too, are said to show that the number of suicides and crimes of passion is highest during these two months.
THE top of Mount Giultschi, a 14,700foot peak in the Italian Alps, recently was reached for the first time by a party of American mountain climbers, headed by Albert Rand Herron. The same group is planning to scale Mount Elburz, in the Caucasus, which, 18,570 feet high, is the loftiest peak in Europe.
NEARLY 40,000 girls and women will be able to enjoy the luxury of sealskin coats or wraps this winter as a result of the record catch of seals made in the Bering Sea last summer. The number of skins collected was 39,253, the greatest harvest in forty years.
STEEL as a wear-resisting material for street pavement is to receive a test at Chicago, where an experimental strip ten feet wide and 120 feet long has just been laid. Wavy strips of steel form a wide mesh an inch and a quarter deep similar to a steel floor mat.
THE entire population of Sing Sing Prison, at Ossining, N. Y., can listen to a radio program at one time, through a hookup designed and installed by one of the prison ’s inmates who was an electrical expert before entering the prison. The system connects more than 2,000 headphones and twenty-one loudspeakers with a central radio receiving outfit.
AN ELEVATED railway for shifting scenery is the latest device for saving time and labor employed by a large moving picture company in Hollywood, Calif. An electrically operated railway, more than two miles long, has been suspended in the air between the construction shops and the company’s seven stages.
SAILING on an even keel, a ship, photographed with a new revolving camera recently tested in Hollywood, Calif., may seem to moving picture audiences to be rocking violently in the grip of a hurricane. By a few turns of a crank, an airplane may be made to perform in illusion its repertory of tail spins, loop-the-loops, and other thrilling stunts without actually once departing from a straightforward horizontal course.
WHEN George Kent, a fifteen-yearold boy of Clifton, N. J., wound in a thousand feet of twine the other day, he pulled to earth a green kite which is said to have broken the world’s record for an “endurance flight.” It had remained aloft twenty-two hours and twenty-one minutes.
INSECT hunting may become a popular pastime aboard ship if the suggestion of Dr. T. D. A. Cockerell of the University of Colorado receives the attention of voyagers. On a trip around the world recently, the professor noticed that the bright lights of the ship at anchor attracted insects from the shore.
THEATER programs that can be read in the dark are used by a London, England, playhouse. They are printed on black paper. The ink used is white and it contains a radioactive element. Seen in the dark, the words glow like the hands of a radium watch.
ONE of the costliest coats in the world is worn by a tree. As much as $4,000 is paid for the white-spotted bark of a variety of cinnamon tree growing in French Indo-China. The tree reaches a height of thirty or thirty-five feet. When it is stripped, the bark is divided into three parts.
STEAM heat from a volcano will warm guests in the new Kilauea Hotel, on the island of Hawaii, if present plans are carried out. According to Dr. T. A. Jaggar, director of the Hawaiian Volcano Observatory, volcanic steam escaping from four holes drilled in the heated rocks beneath the structure will be carried to a huge boiler to raise the temperature of water which will be piped throughout the hotel.
A LAND where worry, care, and illness are virtually unknown and evil is reduced to a minimum was recently described by Dr. John C. Hill, Director of the Department of Religion, Archeology, and Anthropology of the University of Southern California upon his return from a trip to the East.
WHEN it comes to endurance records, long-lived fires deserve the championship. A fire in a refuse dump at Rikers Island, near New York City, for example, has resisted for fifteen years all attempts to extinguish it. Yet this is a mere baby compared to the famous Kentucky coal mine fire that burned for half a century and was put out only when a near-by river was diverted into the shaft of the mine.
EQUIPPED with the features of the most up-to-date railroad station, the palatial new terminal at the airport of Los Angeles, Calif., now nearing completion, will provide luxurious accommodation for arriving and departing planes with their passengers.
CHASING balloons in automobiles is the latest diversion of French society women. The first balloon-chasing contest was held recently at St. Cloud, and is reported to have attracted hundreds of entrants. As fifteen small balloons took the air, the women, in automobiles, set out in pursuit of them, the idea of the sport being to follow by road the route taken by the aircraft and to telephone back to the starting point as soon as a balloon was found to have landed.
ENCASED in a shell of scaffolding, St. Paul’s Chapel, New York City’s oldest church building, located in the heart of its downtown section, presented a curious appearance during recent renovating operations. The building was erected in 1764.
THE great locks of the Panama Canal opened and closed for 6,413 vessels, representing twentythree nations, during the year which ended last June. Of that total, the United States supplied more than forty-two percent, or 2,700 vessels.
Answering the Questions Most Frequently Asked about the Qualities of the Year's Best Electric Receivers
ALFRED P. LANE
DECIDING what radio receiver to buy is harder this year than it ever was before. And, curiously enough, the difficulty now is due to the fact that there are so many really fine sets on the market. Cabinet designs have become so standardized that dozens of different radio sets varying widely in power, price, and so on look practically alike except for minor details in the finish of the cabinet.
AFTER subjecting many of the nationally sold radio sets to careful tests in its laboratory at New York University, Popular Science Institute has prepared a list of those found to be highly efficient and of good value according to 1930 standards.
How to Silence the Squeals in Screen Grid and Audio Amplifier Circuits — Finding the Limit of Selectivity
APIECE of apparatus that is indispensable to the dentist may be employed by the amateur radio fan to rig up a handy troubleshooting lamp. The illustration on this page shows how the device is made by soldering the handle of a small dental mirror to a pencil-type nickel plated pocket flashlight.
IN THEORY, at least, the screen grid tube is so constructed that there is no internal capacity between the elements of the tube to cause feedback and consequent oscillation or squealing. In practice, however, the screen grid tube is not absolutely perfect; and, furthermore, it is extremely difficult to shield a radio set to meet the theoretical requirements.
THE only practical way to convert direct current into alternating current in quantities sufficient to operate one of the new electric type radio receivers is to use a rotary converter or motor generator unit. The motor generator consists of a direct current motor coupled directly to an alternating current generator.
AUDIO amplifier circuits play queer tricks at times. An audio amplifier, for instance, may operate for months without trouble and then suddenly produce oscillations ranging from a thumping “putt-putt” to a high-pitched squeal. Various conditions may cause this behavior.
THE theoretical limit of selectivity would be reached by a radio set that would receive on a single wave length or frequency; but if such a set could be constructed it would be useless for broadcast reception. It would tune so sharply that music or speech would be unintelligible.
An Architect Tells How to Save Money by Spending It at the Outset for the Best Materials and Workmanship
ROGER B. WHITMAN
THE illuminating experiences of the Kerseys in planning the materials for their new home are concluded in this article, in which they learn the economy of firstclass construction. In another helpful article next month, Mr. Whitman will tell how to get the most out of electricity in wiring the home for lighting fixtures and labor-saving appliances.
"GOT time to reline my brakes this morning, Gus?” Kellogg called as he drove up to the Model Garage. “The linings are nearly worn through.” “Sure thing!” Gus Wilson replied as he swung the doors open. “Run her-inside over near the bench.” Kellogg was rated as a good customer at the Model Garage.
A MODEL railway is, after all, merely a miniature edition of one of our real railroads. And, subject to the limitations of time and space, the model railway owner is faced with all the problems confronting the management of a real railroad.
FOR individual Christmas greetings, photographic cards are ideal in that they can be made to reflect the sender’s personality. One need not be expert in using a camera to prepare these cards since the photographic work can be done by a commercial photographer and finisher.
WHAT amateur mechanic can look at Mr. Evans’ workshop without a feeling of envy? Yet even if most of us cannot hope to have a shop so well equipped, we can emulate Mr. Evans in selecting only high-grade tools and machines, and in arranging them in an efficient and orderly way.
A Spray Gun for Oiling Hard-to-Reach Places—And Other Helpful Suggestions for the Automobile Owner
WHEN the runway to the garage is practically on a level with the garage floor, even a light fall of snow will interfere with opening the doors the full distance necessary to allow the car to drive out of the garage. Furthermore, if the approach to the garage is of concrete and the clearance is small, water getting under the concrete will freeze and lift it enough to jam against the bottom of the doors.
MANY jobs around an automobile are hard to do, not because they are inherently difficult from a mechanical standpoint, but because space is so limited that the hand cannot properly approach the work. One operation of this sort is that of replacing the valve pin after the valves have been ground.
THE harder it is to get at a bearing to lubricate it the more likely is the lubrication to be neglected. While the modern automobile is so constructed that lubrication is as easy as possible, there are many places that still are hard to reach, such as the clevis joints in the brake mechanism.
MANY open cars are so constructed that the windshield is in two sections. Usually a rubber strip is supplied to fit in between the two sections to keep out the rain. This strip, while effective in keeping out the rain, does not improve the car’s appearance and is a disturbing black line across the line of vision.
EACH month POPULAR SCIENCE MONTHLY awards a prize of $10, in addition to regular space rates, for the best idea sent in for motorists. The winner of this month’s prize is D. L. Siverd, of Commodore, Pa., who suggested the garage door clearance device in Figure 1.
Second Article in a Series on Building a Schooner Model— Blueprints Are Available with Complete Full Size Drawings
E. ARMITAGE McCANN
FOR those who are thrilled at the mention of the sea, the building of this small-scale reproduction of the famous fishing schooner Bluenose should prove to be an interesting and pleasant pastime. If you missed the first of these articles (P. S. M., Nov. ’29, p. 79), which dealt with the construction of the hull, you can obtain full size drawings of the completed model with details of each difficult part by sending for Blueprints Nos.
MANY kinds of paint coatings for cement floors are now on the market and are very efficient in that they act as an attractive finish for the floor and also protect the surface to some extent against the ravages of wear in the form of powdering away and cracking.
How to Acquire InstrumentLike Accuracy in Judging Hardening Colors — Tricks in Controlling the Process
WHEN a mechanic is familiar with the theory of hardening tool steel (see P.S.M. Nov. ’29, p. 94), he naturally asks two questions: How can I obtain the necessary practice in judging the hardening colors? What is the best method of arranging the equipment and carrying out the operations used in hardening?
BUILD a forge fire to the depth of 6 in. Break the coke up into small pieces, place the work on top of this, and build a fire-brick wall around it. Next, fill in the spaces between the wall and the work with small pieces of charcoal. Heat the material with a very light blast until the charcoal is fully ignited and keep the charcoal burning until the work becomes redhot.
YOU can saw to a curved line if you grind away about half the width of the hack saw blade between holes. Doing good work is only half of being a good mechanic; taking care of machinery and tools is the ether half. Deep holes can he drilled better in the lathe than in a drill press; for as the work revolves the drill tends to go to the center, while if the drill is revolving it tends to move out.
THE curved outlines of these attractive hanging bookshelves make an ideal problem for studying the use of the motor-driven jig saw. In earlier articles, the writer has told how to use many other home workshop machines, illustrating the processes in each case by some piece of furniture.
A PLAY screen that resembles a house and can be folded for storage when not in use makes an ideal addition to any child’s Christmas toys. As a school project, its construction is such that it makes an instructive shop problem; and since it is almost indispensable as part of the kindergarten equipment, the shop department can receive monetary credit for the work and materials that were used in construction.
THE attractively embossed billfold illustrated could well be included in any list of Christmas gifts. It accommodates both the new and the old size bills and can be made by the easy and effective method of embossing previously described (P. S. M., Nov. ’29, p. 102).
THE most important tool in model airplane building is a sharp knife. Some model builders prefer using a safety razor blade, feeling that it is sharper and therefore more efficient and quick cutting. This is very true, but it also presents the ever-present danger of a badly cut finger.
THE miniature motor-driven workshop machines shown, consisting of a lathe, drill press, sander-jointer, and circular saw, not onlyserve as educational toys for children having a mechanical turn of mind, but will actually turn out work that is accurate enough for model parts and small toys.
THE accompanying illustration shows an attractive cigarette box for the end table or smoking cabinet, which may be made easily in the home workshop. The only tools required are a saw, a plane, and a chisel. For the school shop with such equipment as the dado saw and jointer—and when there is no objection to having the boys make smoking equipment for gift purposes or for sale—the making of a number of these boxes forms an instructive exercise in mass production.
ONE of the most useful members of the knot family is the square or reef knot. It is employed for tying two rope ends together and is perhaps the most satisfactory device for securing the cord on packages. Its many other uses include the tying of bandages, for it can be adjusted to just the right degree of tightness.
LONG shafts, which must be handled between centers for milling machine operations, frequently give trouble by springing down in the center. Sometimes blocks of various shapes are used; at other times there is a steady rest of some sort with the milling machine equipment.
TO ASSIST you in your home workshop, POPULAR SCIENCE MONTHLY offers large blueprints containing working drawings of a number of well-tested projects. Each subject can be obtained for 25 cents with the exception of certain designs that require two or three sheets of blueprints and are accordingly 50 or 75 cents as noted below.
FROM building model sail planes much can be learned regarding plane construction and the principles of flight. The glider illustrated, which is easily made, is a reproduction of the famous Darmstadt sail plane. Models of this type have flown on the level for sixty feet when launched from a height of a little over seven feet.
THE operation of applying glue, contrary to the prevalent idea, is one of the utmost importance in the making of any jointed woodwork. The glue must not only be of the best quality, but it must be used in the right way. What are the common kinds of glue?
MANY machine hack saws are wasteful of saw blades, especially when large quantities of small-sized stock are cut. On stock up to 3 in. in diameter perhaps only one third of the length of an 18-in. blade is used. It thus happens that blades are sometimes discarded when they still have two thirds or more teeth that are practically unused.
DIFFICULTY is often experienced in disk-grinding thin pieces like the flange shown at A in the accompanying illustration. The grinding of thin pieces is considered an unpleasant operation, as it brings the fingers close to the grinding wheel.
THE difficult and often dangerous job of handling large sheets of metal may be made easy and safe by the holder illustrated. It is simply a loop of ⅝-in. steel rod just large enough to fit a man’s hand, and with about 3 in.at one end turned back near the loop, leaving a space large enough to admit the metal.
FOR anyone who wishes to add a little touch of the modernistic to his room and is handy with woodworking tools, the desk shown is an especially interesting project. The construction is simple, and the finished product is serviceable and attractive looking.
MANY novel Christmas tree effects can be obtained by using the homemade spotlight illustrated below. Its cost is so far below that of the commercial type that it can be conseidred as negligible, and at the same time its effectiveness is the same.
IN MAKING the combination shoe case and polishing outfit shown, any easily worked wood may be used. It is made up of two ends ¾ by 10¼ in. by 5 ft. 5 in., one top ¾ by 10 by 20 in., one bottom the same size, and one plywood back ¼ by 20 in. by 5 ft. 5 in.; boards may be used for the latter if preferred.
NOTHING in the line of decorative metal work is easier to make than a hammered copper letter opener. Aside from being work well within the limits of skill possessed by the average worker, the finished article is one that may well grace the finest mahogany desk or table.
THAT unused doorway in your house, through which no member of the family ever passes, may be easily fitted with builtin furniture, which, if constructed separately, would occupy considerable space in the room. The drawings below show how to build a desk, a linen closet, a service closet, or a combination breakfast table and ironing board.
TO COVER a circular saw that is not provided with a commercial guard, it is possible to construct a convenient device for shielding the blade as shown in the accompanying illustrations. From a 1-in. board, saw out a piece resembling the part marked B in the diagram.
IVORY is becoming scarcer and scarcer as time goes on, so that those of us who are fortunate enough to possess ivory objects should take care to keep them beautiful by periodic restoration of the natural tint. Objects cut from ivory that have become discolored can be restored to their original condition of beauty by any one of the three methods to be described.
THE case illustrated, aside from being an attractive receptacle for soiled linen, has the added advantage of being so constructed that the full, heavy laundry bag can be removed easily by taking out the front of the holder. No heavy lifting is necessary. For the family that is now stowing its soiled linen and clothing wherever it will best be out of sight, this case would be a much appreciated addition to the house furnishings.
THIS inexpensive electric toaster was designed by E. A. Rerucha, of Wakefield, Mich., and won second prize in the electrical division of a national shop problem competition for teachers conducted by the Educational Department of POPULAR SCIENCE MONTHLY.
BY SETTING an ordinary watch in this artistic little case made from a single block of mahogany or other hardwood, an attractive, serviceable traveling or desk clock can be made. The case is 2½ in. square and 6 in. long. It is cut out at the top as indicated, so as to leave an ornamental triangle of wood, which conceals the projecting stem of the watch.
SKILLFUL handling of a brush and thorough brushing-in of the painting materials are the fundamentals of painting. To these the amateur should give close attention, because they largely determine the success of the work; provided, of course, that high-grade paint and first-class brushes are being used.
FOR applying delicate decorations on ship models, for coloring flags, pennants, shields, and various ornaments, and for marking out minute panels, windows, and doors, a new type of colored indelible pencil can be used with far greater ease than a paint brush.
FOR stairs that are inclosed by two walls, a graceful and serviceable handrail can be made from 1¼-in. cotton rope, velvet, and a few brass stanchions of the type having a hole all the way through and sold by marine dealers. The stanchions should be brass, preferably 3½ in. high with a 1¼-in. hole and a 3-in. base.
A PICTURESQUE and unusual table lamp can be made as illustrated on the following page from a large, unhusked coconut and some palm stems or shrubbery. The coconut is sawed in two and the meat removed, after which the nut is dried for several days.
WHEN the tube method of drilling— or, more properly, grinding—glass is to be used, the most difficult part of the work is starting the drill. An efficient guide can be made from a cut iron washer with a hole slightly larger than the drill tube.
This veteran pilot of sixteen years’ experience made his first flight as a boy by jumping off a shed on a barn door. Since then he has flown nearly 4,000 hours. Readers of this magazine remember him as one of the instructors who taught Larry Brent how to fly.
PICTURES of water fleas are being hung up nowadays in most of the world’s laboratories of biology. For these tiny creatures are likely to prove among the most interesting, scientifically, in the world. Thanks to researches by Dr. Arthur M. Banta, of the Carnegie Institution, water fleas already have supplied one of the best examples of the operation of heredity, and almost the only example known to science of the artificial control of sex.