In the body of the bomb was a viscous mass of benzine hydrocarbons, while the lower part of the receiver contained a mixture of potassium perchlorate and paraffin. The central tube apparently contained a mixture of aluminum and sulfur.
Fig. 108.—Aerial Incendiary Bomb,
November, 1916.
Fig. 109.—German Incendiary Bomb,
Scatter Type.
All dimensions in millimeters.
Later the Germans used a scatter type of bomb ([Fig. 109]) which was designed to give 46 points of conflagration. Each of these 46 small cylinders contained 50 grams of an air incendiary material. They were arranged in layers, packed in with very fine gun powder. The bomb is ignited by a friction lighter which is pulled automatically when the bomb is released from the aeroplane. The bomb is constructed to burst in the air and not on striking the ground. The upper part of the projectile consists of a cast iron nose riveted to the sheet iron body of the bomb. When the explosion occurs, the nose is blown away and the small incendiary cylinders are scattered in the air.
The incendiary material appears to be a mixture of barium nitrate and tar. Its incendiary power is very low because combustion takes the form of a small flame of very short duration. It should, however, be very valuable for firing inflammable materials.
British Bombs. The early British bombs were petrol bombs, which were used without great success for crop burning. Phosphorus bombs were then used for attacking aircraft. But the most successful incendiary is the so-called “Baby Incendiary Bomb.” This is a 6.5-ounce bomb with an incendiary charge of special thermit. These small bombs are carried in containers holding either 144 or 272 bombs. The former container approximates in size and weight one 50-pound H.E. bomb and the latter one 120-pound H.E. bomb. The bomb contains a cartridge very much like a shot gun shell which, on impact, sets down on the striker point in the base of the body, and causes the ignition of the charge. It is claimed that the cartridge of the B.I. bomb burns when totally immersed in any liquid (water included) and in depths up to two feet the flame breaks through the surface.
French Bombs. The French used three types of incendiary bombs, a special thermit (calonite), the Chenard and the Davidsen. The Chenard bomb is a true intensive type and is thought to be very successful. It functions by means of a time fuse operated by the unscrewing of a propeller, before striking the ground, and reaches its target in flames. Its chief disadvantage is the small amount of incendiary material which it carries. The Davidsen bomb expels its charge as a single unit and is not considered as valuable or as successful as the Chenard.