a term adopted in the new chemical nomenclature, to express the acidifying principle; from Oxygen, "acid," and genere, "to generate." It is not found naturally in a separate state, but always combined with some other substance. In its aeriform or elastic state, it is called oxygenous gas, and is the same as the dephlogisticated air of Priestley and Cavendish, the empyreal air of Scheele, the vital and pure air of other chemists. See Oxygen, Chemistry Index.