Page:Popular Science Monthly Volume 88.djvu/744

 Out-Periscoping the Periscope

��/% N observation apparatus with great- /A er range than the periscope has been constructed by Joseph de Falco, of Vineland, N. J. With it, ob- servations can be made by a submarine without the vessel endangering itself by coming so close to the surface as the present submarine periscope requires.

The "eye" of the new apparatus is an inverted semi-spherical mirror. This mirror is suspended from the end of a horizontal rod. The rod is attached to an adjustable mast, and is of the proper length to bring the mirror directly above a vertical, chimney-like tube in the roof of the house. The "eye" may be raised or lowered by means of a rope which passes up over pulleys attached to the horizontal arm and mast and then down into the hut where the end is within im- mediate reach of the observer.

In making observations, an image of all objects within a complete circle are reflected by the eye-like mirror. This image is magnified as it passes through a series of magnifying lenses directly be-

���neath it, but far below in the periscope build- ing or cage. The reflec- tion from the observa- tion mirror "eye" is finally projected on a screen in front of the observer.

The arrangement of these lenses is shown in the accompanying dia- gram. The uppermost one is stationary, being mounted in the vertical tube on the roof of the building be- 1 o w. The other lenses are all a d - justa- a b 1 e and m a \'

����Diagram of construction of ob- servation apparatus, showing the "eyes" and the lenses

��The innocent-looking hut appears to be a shed with an electric light pole above it

be regulated according to the height of the mirror outside, the object being, of course, to focus the picture on the ob- servation screen below.

This screen is, in reality, a semi- spherical shell with the concave surface uppermost. It is made of white enam- eled glass, so as to make a distinct image of the outside world. This ob- servation apparatus rests on a table of suitable height for a man to sit comforta- bly and watch proceedings without in- curring the risk of being seen and fired at. The picture thus obtained is in the nature of a bird's-eye view, since the mirror is located at a considerable height.

On the battle-fields of Europe a method

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