This explosive agent will probably be used for spar torpedoes, when gun-cotton or dynamite are not employed.
B.—Explosive Compounds.
Nitro-glycerine.—Nitro-glycerine is formed by the action of nitric acid upon glycerine at a low temperature.
The manufacture of this compound consists, first, in the slow mixture of the glycerine with the acid, at a low temperature; secondly, in washing the nitro-glycerine from the excess of acid with water.
The nitric acid before use is mixed with a certain proportion of strong sulphuric acid, so that the water formed during the reaction may be taken up, and thus any dilution of the nitric acid is prevented.
Nitro-glycerine is composed of carbon, hydrogen, nitrogen, and oxygen, as indicated by the equation C3H5N3O9.
Properties, &c.—At ordinary temperatures nitro-glycerine is an oily liquid, having a specific gravity of 1·6. Freshly made it is creamy white and opaque, but clears and becomes colourless on standing for a certain time, depending on the temperature.
It does not mix with, nor is it affected by, water. It has a sweet, aromatic taste, and produces a violent headache if placed upon the tongue.
The opaque, freshly made nitro-glycerine does not freeze until the temperature is lowered to 3°-5° below zero, F., but, when cleared, it freezes at 39°-40° F. Nitro-glycerine freezes to a white crystalline mass, and in this state it can be thawed by placing the vessel containing it in water, at a temperature not over 100° F.
If flame is applied to freely exposed nitro-glycerine, it burns slowly without explosion.