Page:Popular Science Monthly Volume 89.djvu/497

 Popular Science Monthly

��Vol. 89

No. 4

��239 Fourth Ave., New York

October, 1016

��$1..50 -Annually

��Wild Animals That Photograph

Themselves

��PHOTOGRAPHING by flashlight is one of the more recent advance- ments in the field of picture-taking which has helped to secure for photog- raphy a permanent place among the arts. Paul J. Rainey, the explorer and hunter of wild animals, proved several years ago at the first exhibition of his wild animal flashlight pictures taken in Africa, that this class of photography offered a virgin field to the manufacturer of apparatus and to the man behind the camera. Soon after this there was an awakened interest in animal film shoot- ing in preference to gun or trapshooting.

At the present time photographic flashlight apparatus has been developed to a point where guesswork is eliminated and where it is possible to photograph any object in motion. To do this it is necessary for the camera to catch the object in motion just at the instant when the flash powder is giving forth its brightest light. This requirement calls for a high-speed shutter to stop the motion on the plate of the object being photographed. With a flashlamp recently perfected by William Nesbit the shutter is automatically snapped at exactly the moment when the light from the flash powder is most intense. His apparatus has been widely used to take flashlights of wild animals in their nati\'e haunts and has given uniformly good results.

When flash powder is ignited it does not burn up or explode instantly, as might be supposed. It burns more and more brightly until it reaches its point of greatest brightness, from which point on it dies down until it goes out. This

��whole operation takes at the most one fifth of a second. However, good pictures will be obtained only if the camera is snapped during this fifth of a second, when the flash powder burns the brightest.

On the other hand, this point can never be definitely determined before taking the picture. It changes for differ- ent powders and also varies for the same powder, since the powder may become slightly damp and will not burn in the same way. It is evident, then, that to snap the camera at precisely the right moment is not so eas\' as it might appear.

The flashlamp devised by Mr. Ne.sbit consists of an aluminum container to hold the flash powder, a cover for this container, a mechanism to fire the powder, and an attachment which will automatically snap the shutter of the camera at the moment when the flash powder is burning brightest. The unit is waterproof, and so compact that it can be readily attached to a tree or other convenient support.

The flash powder is placed in a box made waterproof by a coat of parafiin and is then placed in the space provided for it in the flashlamp. The powder is fired either by a blank cartridge or by an electric spark furnished by a dr>' battery. A firing-pin, controlled by a spring and a trigger, similar to those used in a rifle or revolver, sets off the cartridge.

When taking a flashlight of an animal, a wire is attached to the trigger and then tied to bait of some sort. The animal is attracted by the bait, and if it touches it, the wire is pulled, which, in turn.

��483

�� �