Nitrous Oxide, or LAUGHING GAS

N2O. Sp.gr. 1.527. Colorle gas, with a sweetish taste and odor; soluble in water. It supports combustion almost as well as oxygen, can be easily liquefied at 0° C., 30 atm.; sp. gr. of liquid.90, and is put on the market in this form in metallic cylinders. It is made by heating ammonium nitrate. If inhaled, it causes unconsciousne and insensibility to pain, hence it is used in minor surgical operations. Its anæsthetic properties were discovered by Sir Humphrey Davy 1800. It was first used in extraction of teeth by Horace Wells, of Hartford, Conn., Dec. 1844. The gas was discovered by Priest ley 1776.