The Romance of Modern Chemistry

EXPLOSIONS AND EXPLOSIVES flammable material. This was then ignited, and when the combustion was over the case of wet gun-cotton was re- covered, none the worse for its baptism of fire. Wet gun-cotton, however, can be at once exploded by detonation, provided only that a little of the dry material is in contact with the detonator. The old saying, there- fore, “Keep your powder dry,” is applicable only in a very limited sense to gun-cotton. It is, as a matter of fact, always stored in the wet state, containing about twenty per cent, of water; and it may be used in this condition in torpedoes and submarine mines. A more dangerous explosive than gun-cotton is nitro- glycerine, a liquid obtained by the action of nitric acid on glycerine. The most extraordinary precautions have to be taken in the handling of this material, and it is only by a strict observance of these that a repetition of the disasters which marked the early years of nitro- glycerine manufacture is avoided. So serious were the accidents which occurred with nitro-glycerine some forty years ago that several governments went the length of altogether prohibiting the use of the explosive. Chemists soon discovered, however, the necessary precautions that have to be taken in the manufacture and handling of nitro-glycerine, and at the present day large quantities of this explosive are prepared. In a nitro-glycerine factory the sheds in which the various operations are carried on are well separated from each other, and surrounded by banks of earth or sand. In order to avoid any risk of a spark being produced and setting off the nitro-glycerine, all workers have to wear special clothing. Boots with iron nails are abso- lutely prohibited, and in their place shoes of rubber, felt, or sown leather are employed. Girl operatives 177 m