Page:Popular Science Monthly Volume 56.djvu/320

306 when ignited, but it can be quenched by pouring water upon it. When confined in the chamber of a gun or the bore-hole of a rock, gun cotton will burn like gunpowder when ignited, if dry, and produce an explosion, but, in common with nitroglycerin and other high explosives, gun cotton is best exploded and develops its maximum effect when detonated, a result which is secured by exploding a small quantity of mercury fulminate in contact with the dry material.

Mercury fulminate is made by dissolving mercury in nitric acid and pouring the solution thus produced into alcohol, when a violent reaction takes place and the fulminate is deposited as a crystalline gray powder. This powder is loaded in copper cases and, after drying, it is primed with dry-mealed

 In the bottle is indurite in flake grains. The larger grains are cylindrical and hexagonal multiperforated United States army grains. The bent grain in the foreground, looking like a piece of rubber tubing, is a grain of Maxim powder with a single canal. The flat strips in the foreground on the left are grains of the French B. N. powder. The flat strips in the foreground on the right are grains of the United States navy "pyrocellulose" powder.

gun cotton, the mouth of the case being closed with a sulphur-glass plug, through which pass two copper leading wires joined by a bridge of platinum-iridium wire, two one-thousandths of an inch in