GUN COTTON.
Although there appears no prospect of Gun cotton being used in the British service as a substitute for gunpowder, it is advisable that every Artillerist should be cognizant of its merits and demerits; for circumstances may arise when this new impulsive power may be advantageously employed. The exploding cotton is thus prepared:—Common well-cleaned cotton is dipped for about half a minute in highly-concentrated nitric acid (made by the distillation of ten parts of dried saltpetre, and six of oil of vitriol), and then instantly placed in water, which must be often renewed, in order to free the cotton from the acid with which it is impregnated. Care must then be taken that all the knotty particles of the cotton are properly disentangled, and that it is thoroughly dried. After the explosive preparation is ready for use, the smallest portion explodes when struck on an anvil with a hammer, like fulminating-powder; when kindled with a glowing body, it takes fire just like gunpowder; and, when used in a gun, its operation, though in a far greater proportion to its weight, is similar to that of gunpowder. Gun cotton is employed in the same manner as gunpowder: a piece of it is rammed down the barrel, then a bit of wadding, and after that a ball; a copper cap ignites and explodes the cotton.
To Dr. Otto, professor of chemistry in Brunswick, we are indebted for the foregoing description of the preparation of the explosive cotton; and the intrinsic value of this impulsive agent has been ascertained by Colonel Mordecai, at Washington, in 1845, 1847, 1848. The following are the results of this scientific officer’s experiments for the purpose of determining the fitness of Gun cotton, as a substitute for gunpowder in the military service:—
1. Explosive cotton burns at 380° Fahrenheit, therefore it will not set fire to gunpowder when burnt in a loose state over it.
2. The projectile force of explosive cotton, with moderate charges, in a musket or cannon, is equal to that of about twice its weight of the best gunpowder.
3. When compressed by hard ramming, as in filling a fuze, it burns slowly.
4. By the absorption of moisture, its force is rapidly diminished, but the force is restored by drying.
5. Its bursting effect is much greater than that of gunpowder, on which account it is well adapted for mining operations.
6. The principal residua of its combustion are water and nitrous acid; therefore the barrel of a gun would be soon corroded, if not cleaned after firing.