"In an evil day... Beccher and Stahl, two men of unquestionable genius, devised a theory of combustion which led all chemistry astray for half a century. According to their view combustion consisted in the emission from the combustible of a peculiar fiery principle, to which the name phlogiston was given. It was present in all inflammables, however different their appearance and properties. When they burned, it passed out of them into the air which surrounded them, and by its loss they became changed in character and quite incombustible; but if phlogiston was restored to them, they recovered their original appearance and properties, among the rest, their combustibility."