Page:Popular Science Monthly Volume 88.djvu/392

 Inventions the War Has Brought Out

��A Russian portable shield captured dur- ing a retreat and now used by the Germans. This shield is made of bullet-proof steel and is admirably designed to shelter five riflemen who protect their trench- digging com- rades. The shelter may be taken to pieces in a very short time and packed for trans- portation in motor trucks

���Listening to the sound of heavy guns with the aid of a tin-can telephone receiver. A tin can, suspended from a copper wire which is wound about a pencil or penholder pressed against the bone back of the ear, makes an excellent instrument for detecting these sounds when they cannot be heard otherwise

���An ingenious French device for photograph- ing the German posi- tions. A special cam- era is attached to a kite, and when the proper altitude is reach- ed, the photographs are taken automatical- ly. Occasionally the kite is sent up from an automobile, and is towed to the desired locations. One of the interesting phases of the war has been the use of kites, even man- carrying kites, in war observations. A camera can well take the place of the man, especially in a kite. The distance from the ground can be accurately estimated by means of a theodo- lite, the instrument used by surveyors

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