Gunpowder

A well-known explosive mixture, whose principal employment is in the discharge, for war or sport, of projectiles from fire-arms, and for mining purposes. The ingredients in gunpowder are saltpetre, charcoal, and sulphur. Slightly different proportions are employed in different countries. In the United States the proportions are 75 to 76 saltpetre, 14 to 15 charcoal, and 10 sulphur. Charcoal is the combustible ingredient; saltpetre furnishes the oxygen nece ary to support a rapid combustion and to change the whole ma into gas, and sulphur adds consistency to the mixture and intensity to the flame, besides rendering the powder le liable to absorb moisture; increases the volume of gas by preventing the formation of a solid pota ium carbonate, and by increasing the temperature. In the manufacture of ordinary powder, the operations usually employed are pulverizing the ingredients, incorporation , compre ion , granulation , glazing , drying , and dusting . The ingredients are pulverized by placing each separately in barrels which contain bronze or zinc balls, and which are revolved rapidly for several hours.