HOW CAMERA SHUTTERS WORK
CAMERAS are constructed to be light-tight, and yet in order to make an exposure it is necessary to let light into the camera and onto the film. This requires a special mechanism called the camera shutter. It is so designed that when a release is pressed, it will move, let light into the camera for a moment or so, and then close and protect the film again from the light. As films have been made more sensitive and shorter exposures made possible, the design and construction of camera shutters has been improved until today there are shutters that split seconds into almost unbelievably small fractions and let light into the camera for just that fractional part of a second. Most of the smaller hand cameras with which we are familiar are fitted with one, or even both, of two types of shutters.
UNDER-SEA TRACTOR-SPHERE ROAMS OCEAN FLOOR
NEWEST of mechanical monsters intended for under-sea exploration is the tractor-sphere being designed by Otis Barton, builder of the bathysphere used by Dr. William Beebe in setting a new world’s diving record of 3028 feet.
The new invention, intended to be driven into the sea from the beach level under its own power, might be classed as a bathysphere mounted on caterpillar treads. Powerful electric motors operating from sealed-in storage batteries would move this undersea tractor over the rocky slopes and pinnacles of the ocean floor.
Fire Fighters Play Poker in Flames
LOS ANGELES firemen have at last solved the problem of getting rid of kibitzers at poker who persist in looking over the player’s shoulder. Clad in their asbestos suits, and using a deck of metal cards, the two firemen in the photo above sit down to have a quiet game while flames lick at their fireproof anatomies.
This novel game was part of a demonstration of Los Angeles firemen to show that carbon dioxide gas will “freeze” when coming into contact with flames, thus smothering the most stubborn blazes. Their asbestos suits gave them complete protection from the heat and the gas did its duty in putting out fire.
Home Tests show Strange Nature of Chlorine
How to Make Metals Flame and Why Red Flowers Turn White is Explained Here
By RAYMOND B. WAILES
UNTIL you experiment with chlorine, you have missed some of the biggest thrills your home laboratory can give you. Among other things, you can make metals burst mysteriously into flame, remove the color from dyed cloth, and turn a red flower or a scrap of red paper white.
Chlorine, a heavy greenish-yellow gas, is exceedingly active. Few substances can remain uncombined in its presence. Even silver and gold yield to its action under certain conditions. With many elements, it combines with such suddenness and violence that intense heat and a brilliant flash of light accompany the reaction.
FLASH LIGHT ON BIG GUN
A flash light attachment for a big game gun is an unusual piece of equipment accompanying Captain R. Stuart Murray and Major George Witten on an expedition to Honduras, where they hope to bag specimens for the American Museum of Natural History. The five-cell focusing lamp is to be used in night hunting and will aid in drawing a bead on the blinded animal.
It’s Always Fun-Time! When You Own a HARLEY-DAVIDSON
OWNING a Harley-Davidson opens a whole new world of thrills for you! Anytime you get the urge you swing into the saddle and go where there’s fun and excitement ! The whole outdoors is yours to enjoy â€” you can do more and see more â€” as you go “adventuring” on evenings, holidays and weekends. And what a continual round of good times awaits you as you join other fun-loving riders on pleasure trips and gypsy tours â€” or take in race meets, hillclimbs and other thrill-packed events that make motorcycling the world’s greatest sport! See your Harley-Davidson dealer NOW â€” and mail the coupon today!
How Good Are Your Hunches?
If you’ve ever suspected you had psychic powers, here’s a chance to try the famous Duke University tests on yourself and your friends.
By Dr. J. B. RHINE
Director, Duke University Parapsychology Laboratory
A YOUNG graduate student at Duke University dropped in to see me at the Parapsychology Laboratory one afternoon.
“Like to try your ESP?” I invited.
He nodded and I shuffled a deck of special test cards, then cupped my hand to screen them from his sight. We made a . few “trial runs” to test his mood. At first he missed every card and I teased him about doing so poorly. Bridling a bit, he named three of the next five cards correctly. Then, just for fun, I began betting that he would not get the cards right. Without looking at the cards, which were all face down on a table, I said, “I’ll bet one hundred dollars you can’t call the top card!” The student looked off into space a few seconds.
If Your Views on Sex are OLD FASHIONED Read these Modern Books
Man’s Sex Life
At last the truth is written. The great mysteries of sexology torn aside. And now you can get the real truth about the sex question.
This is an age of plain thinking and frank speech. No longer can a big, vital problem like the sex question be hidden as a thing to be ashamed of. People are demanding the truth about these things.
And so Bernarr Macfadden has lifted the veil. He has told the truth about mankind’s most vital problem in a frank, straight-from-the-shoulder style that will appeal to every man who reads his remarkable book.
New Devices for General Use
â€¢ OUR grandmothers boiled eggs by little three-minute sand-glasses, like this one, which tells the long-distance talker what time he has taken.
Washes and Sprinkles
â€¢ ANY garden hose takes these units, which wash and clean the car, and sprinkle the grass and flowers efficiently.
For Jobs in the Dark
â€¢ YOUR light falls just where you look, if you wear these electric “spectacles,” which throw considerable light. Can be worn over glasses.
How Tiros Photographs the World (including Russia)
The day of the high-flying spy plane may be over. America’s camera-toting satellites will soon be ready to take over security reconnaissance work
By S. DAVID PURSGLOVE
IS America’s first military reconnaissance satellite already orbiting the earth? Tiros Iâ€”launched in Aprilâ€”was called a “weather observation satellite.” But it has disturbed top U. S. officials the way weather never could.
Nobody expected the camera-carrying Tiros to do more than demonstrate the feasibility of weather satellites (it actually has come up with significant, although not new, information about weather). But Tiros has embarrassingly done more for military spy satellites than it has for weather satellites.