Nitroglycerin

C,H, (NO3)3. Discovered at Paris in 1847 by Sobrero, and brought into practical use as an explosive agent by Nobel 1863. Sobrero's proce for its manufacture is to pour one part by weight of anhydrous glycerin with constant stirring into a mixture of four parts of concentrated sulphuric acid (sp. gr. 1.845) and two parts of fuming nitric acid (sp. gr. 1.52), the temperature of the mixture being kept below 24° C. by external cooling with ice. After the oily drops have formed on the surface, the mixture is poured, with constant stirring, into 100 parts of cold water: 45 lbs. acid produce 13 lbs. nitroglycerin. It is a colorle , oily liquid, having a sp. gr. of 1.6, and insoluble in water. It burns without exploding, but is easily exploded by concu ion, and is about eight times as powerful an explosive as gunpowder, weight for