Pronunciation: [flOjis´ton] hypothesis regarding combustion.
The theory, advanced by J. J. Becher late in the 17th cent. and extended
and popularized by G. E. Stahl, postulates that in all flammable materials
there is present phlogiston, a substance without color, odor, taste, or
weight that is given off in burning" Phlogisticated substances are those
that contain phlogiston and, on being burned, are "dephlogisticated"" The
ash of the burned material is held to be the true material. The theory
received strong and wide support throughout a large part of the 18th cent.
until it was refuted by the work of A. L. Lavoisier, who revealed the true
nature of combustion. Joseph Priestley, however, defended the theory
throughout his lifetime. Henry Cavendish remained doubtful, but most other
chemists of the period, including C. L. Berthollet, rejected it.