KINDS OF BOMBS
Various kinds of bombs are used for dropping from aeroplanes. A simple pattern shown in [Fig. 1] consists of a thin spherical shell of steel, containing twelve pounds of tetranitranilin, which is an explosive more powerful than melinite. The stem of the bomb, by which it is handled, has an external screw-thread, and carries a pair of vanes. While in the position shown, the bomb is harmless, but as it drops, the vanes screw themselves up to the top of the stem till they press against the stop. This, by means of a rod passing down the center of the stem, “arms” or prepares the fuse seen at the bottom of the bomb, so that it acts at the slightest touch, even on the wing of another aeroplane. The fuse effects the explosion of the burster by means of a primer of azide of lead, which causes the tetranitranilin to detonate with great violence. The whole bomb weighs twenty-two pounds, and an aeroplane usually carries six of them.
The Italians, in their campaign in Tripoli, used similar bombs, but without the special device for rendering the fuse sensitive. These were not a success, as many of them failed to explode in the desert sand, and the Arabs used to collect them and throw them into the Italian trenches at night.