SILENCE IN A VACUUM can be demonstrated with a glass flask and a small sleigh bell. Hang the bell on the end of a length of dowel or glass rod that can be pushed through the hole of a snug-fitting flask stopper; then put a little water in the flask, boil it long enough for steam to drive out the air, remove it from the heat, and fit the stopper in as soon as the steam stops expanding. Cool the flask with running water and shake it near your ear. You will barely hear the bell tinkle, the steam having produced a partial vacuumâ€”sound waves will not travel through a vacuum. But let air in and again shake the flask, and the tinkle will be heard clearly.
No Job Too Tough for Minute-Men Cops
Emergency Division of Police Trained to Handle Tragedies and Freak Accidents of a Great City
By Thomas M. Johnson
A NEW building was going up. Before it stood a big concrete mixer. To chew up stone, gravel, and sand, its vat-like interior had strong teeth, powerful flanges, and cogwheels. To keep these fed, was the job of one man who stood on a running-board and watched those teeth grind concrete. Suddenly the man slipped. Frantically, vainly clutching for safety, he toppled into the mixer’s jaws. Bruised, half-smothered in liquid concrete, he was shocked by violent pain. His leg had been caught in the cogs. Those crunching teeth were tearing flesh and breaking bones. His screams of pain and terror brought men on the run.
What exactly are the books supposed to be protecting them from?
What’s Extra Protection Worth to You?
You get more miles from your car, more life from your engine, with Casite’s extra protection.
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The Need to Make Things
IF, BY some miracle, you could be transplanted backward in time to the days of our prehistoric ancestors, what would be the first thing you would do?
It makes no difference whether you are a banker, a farmer, a politician, or a factory worker, your first action, assuming that you didn’t drop dead at the suddenness of the change, would be to search for food. The second would be to search for shelter both from the elements and from wild beasts. In other words, the two necessities of existence, which you now take so much for granted, would occupy your thoughts to the exclusion of everything else. Guessing what you would do after that depends on the particular kind of primeval wilderness to which you were transplanted. You might, for example, find yourself in a time and location in the past when the struggle for existence was fierce. Getting food and shelter would, in that case, occupy every waking thought until you met death under the claws of some carnivorous beast. And you wouldn’t last long, either, for only the exceptionally skillful in the art of self-preservation lived even to middle age under such difficult conditions.
THE FLIGHT OF ATOMS PHOTOGRAPHED
By W. D. HARKINS
Professor of Physical Chemistry, University of Chicago
An atom is 2,000 times too small to be seen through a microscope and it is apt to stagger the imagination of most people to hear about photographing atoms in flight. Not so long ago an atom was spoken of as the smallest particle of matter, but now it is believed to represent a grouping of electrons around a nucleus, much in the manner that the planets arranged around the sun constitute the solar system.
The Bicycle Comes Back
In amazing revival of fad of the nineties
By John E. Lodge
THE bicycle is back. Four million Americans now pedal along streets and highways. And, last year, factories in the United States turned out 750,000 machines, nearly equaling the peak production of the gay nineties. News items from all parts of the country tell the story of this dramatic boom in popularity.
In Chicago, Ill., for instance, 165,000 persons recently signed a petition asking for cycling paths to be constructed in the city parks. In Washington, D. C, a huge crowd of enthusiastic spectators, last winter, braved frigid winds for hours to watch an amateur bike race. From coast to coast, cycling clubs are i springing up. The veteran League of American Wheelmen has come back to life. The Amateur Bicycle League of America has approximately ninety affiliated clubs; the Century Road Club, promoting amateur races, has twenty-five or thirty, and there are upwards of 300 unassociated clubs in the country.
Movies For Passengers on Long Plane Hops
FULL-LENGTH movies, news-reels, or shorts can be shown to airplane passengers by a new self-contained projection unit (right). Developed by the Air Transport Command and Army Signal Corps, the outfit also provides radio broadcasts and recorded music from sound films, a program being heard either through a loudspeaker or individual headsets. Plane movies entertained many of the War wounded who were evacuated over thousands of miles by air.
Speedy Motor-Cycle Car Runs on Two Wheels
WHETHER it’s a car or a motor cycle would be hard to say, but the inventor of the novel vehicle above declares it has the advantages of both. In motion, it rides upon two wheels, guided by a steering wheel. The driver experiences a pleasant swaying sensation as the machine tips like a plane or motor cycle for the turns. When the driver stops, a pedal lowers a pair of small auxiliary wheels at the sides for support. The photograph shows the odd gas buggy being driven by a mechanic in a tryout run at Miami, Fla. Another model has a seat for a passenger mounted behind that of the driver.
WIRE REPLACES WAX IN NEW DICTATING MACHINE
Unusually clear reproduction is claimed for a new type of dictating machine invented in Germany. In this device the fluctuations of a speaker’s voice, conveyed electrically to electromagnets, leave a moving steel wire traveling through them more or less strongly magnetized according to the intensity of the voice at each instant. To play back the record, the wire is passed through a similar machine where the reverse process takes place and the voice is heard in a pair of headphones. The wire may then be run through a demagnetizer and used again. Wax records are dispensed with, since the wire takes their place. The wire is made of an alloy the nature of which the inventor is keeping secret, but upon which, he says, the success of his device depends. The machine is shown above.
This article was published less than a year after the tomb was discovered.
TREASURES OF ANCIENT THEBES IN NEW-FOUND TOMB
By R.C. Folger
TREASURE that has been variously estimated to be worth from $15,000,000 to $40,000,000, has recently been brought to light upon the opening of a tomb believed to be that of Tutankhamen, who ruled in Egypt over 3,000 years ago.
The first objects to greet the eyes of the entrants to the tomb, were three magnificent state couches, each made of gilt wood with exquisite carvings and decorated with a lion’s head and other emblematic figures. On these rested gilt beds also beautifully carved and inlaid with ivory and jewels, and a number of boxes of rare workmanship. These boxes were inlaid with ivory and ebony with gilt inscriptions.