Page:Popular Science Monthly Volume 91.djvu/344

 Popular Science Monthly

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��This Airplane-Camera Takes 750 Exposures with One Loading

THE greatest work of the airplane is to locate the enemy's strongholds and batteries and then map them. The multiple airplane-camera which the Allies are using — an American invention, by the way-^-can map the German lines with truly marvelous pro- ficiency. Where, in the first part of the war, artist- observers were used to make pencil sketches as accu- rately and as quick- ly as they could, now cameras such as this one are em- ployed to take thousands of pho- tographs at the rate of one a second, if necessary.

One multiple airplane- camera alone is capable of seven hundred and fifty ex- posures with a single loading. The secret of this great capacity lies in its use of ordinary motion picture film. It is con- structed much like the ordinary film camera, with the exception that the turning of the film for a new exposure is accom- plished automatically by the action of a set of gears.

The camera is placed on the airplane so that it will have an unobstructed view downward and slightly for- ward. One pull on the flexi- ble cable, connected with the operating lever of the gears, winds up the previously ex- posed film, sets the shutter, makes the new exposure, and registers its number. A spring instantly brings the lever back into normal posi- tion ready for the next pic- ture. This happens so swift- ly that it is possible to make a continuous record of a flight. In bomb-dropping the camera is capable of tak- ing pictures of the bomb in the air and at the very in- stant of explosion.

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��The camera that takes 750 exposures with one loading

��The Electric Stevedore. It Saved $18,000 in Labor Costs in a Year

BELOW is pictured an electric floor- truck that does the work of ten man- propelled trucks. The pull- ing effort of the single front power-wheel is such that a railroad flat car weighing 33,900 pounds is hauled over sandy soil, carrying several interested observers.

The truck is the in- SHj vention of J. E. Haschke, of Los Angeles, the man at the wheel.

The truck weighs but 1500 pound;?. The mo- tor is mounted on the yoke of a caster wheel, which permits the truck to revolve within its own wheel base; hence its peculiar usefulness upon congested floors. The wheels are rubber- tired. A striking feature is em- braced in the two levels of the truck, one but twelve inches from the floor. Any level of platform desired or demanded by warehouse needs can be provided. The truck will carry a ton on its back and tow several tons more on trailers; or it will carry several tons of iron, for instance, at a time over good streets.

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���It would take ten man-oper- ated hand trucks to do the work of this electric truck

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