Ni′troglyc′erin, a powerful explosive, is formed by dissolving glycerin in equal parts of nitric and sulphuric acids and pouring into water. The process was discovered in 1846 by an Italian chemist named Sobrero, but it was not used for blasting purposes until Nobel, a Swedish engineer, used it in 1861. The danger of explosion was so great in handling it that its mixtures with powdered substances, especially dynamite, are now chiefly used. If lighted in the open air, it will burn usually slowly without an explosion, but if given a hard blow or brought into contact with a red-hot iron it will explode. It begins to decompose at 150° to 180° F., and explodes at 450°, also if allowed to become solid at from 40° to 45° F.; a breaking of the crystals in this form may cause an explosion. It has thirteen times the power of the same bulk of gunpowder and eight times the power of the same weight. It is also used in solution for treating some diseases of the heart and stomach.
