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Page:Popular Science Monthly Volume 90.djvu/442

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426

��Popular Science Monthly

��A Safety Box for Carrying Blasting Caps in the Field

WE are becoming so well acquainted with high explosives that we play with them as if they were toys in our hands. In a single year enough explosives are left in public conveyances by thoughtless people to blow up a dozen mines. In the New York subway, for instance, there have been found cans of nitroglycerine, sticks of dynamite, bombs of all sorts and descriptions, and other explosives in sufficient quantities to rock the whole island were they "touched off." All of which goes to prove that some people think no more of toting a death-dealing article about town than carrying an um- brella. Evidently the pow- der-shy days have passed.

Not long ago a box filled with one hundred blasting caps was thrown over a fifty-foot embankment in- to a quarry, where it bounced around on the rocks with no resultant explosion. The fact that the caps did not explode was due to the box in which they were packed — a safety box for carrying blasting caps in the field. Although blasting caps and dynamite never are carried in the same receptacle, blasting caps have caused some serious explo- sions in the past. Some miners would rather handle a car- load of dynamite than a box of blast- ing caps.

The new safety box shown in the photograph contains one to carry electric the other to carry regular blasting caps for use with fuse. The box is made of oak with a top of pine. It is lined with felt obtain- able at harness shops. The cap board is removable but it fits snugly on, the space between it and the caps being padded out.

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The box can fall off a wagon and cause no more damage than if it contained spaghetti

��two compartments, blasting caps and

��The Race Between Nature and the Scientific Motion-Picture Camera

SOME day the scientific camera-man is going to photograph for us the thousands of movements in nature which we have never been able to see because of their lightning swiftness. This camera-man will have a camera capable of taking five thousand pictures per second — or possibly a camera which takes a continuous motion- picture with no revolving shutter and inter- mittent film movement. He will, in fact, be able to photograph the fastest movements in nature.

In Germany a picture has been taken in one ten-millionth part of a second. The ordinary motion-picture camera takes sixteen pictures a second. This means that a considerable portion of the action is not photo- graphed. In filming a motion-picture drama this loss means nothing; but in scientific research the films would be worth- less. At present the fastest motion-picture camera takes pictures at the rate of two thousand per second. Naturally this camera misses very little of the action and shows us many wonders of nature which the human eye has never looked upon. For instance, take the beat of the hon- ey bee's wing — one of the most rapid movements in na- ture. A picture taken in a sixteenth of a second misses it completely. But a new camera in which the picture is taken by an electric spark has given us the first view of a bee in flight. A bee was launched almost upside down before the camera, the film showing its efforts to right itself. It regained its equi- librium so quickly that no eye could pos- sibly have followed its movements, but twentysharf>lyfocussed pictures were taken.

��The box carries one hun- dred blasting caps for work. It is impossi- for them to explode

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