1660-1734. German chemist who produced a
fallacious theory of combustion. He was
professor of medicine at Halle, and physician
to the king of Prussia. He argued that
objects burn because they contain a
combustible substance, phlogiston. Substances
rich in phlogiston, such as wood, burn almost
completely away. Metals, which are low in
phlogiston, burn less well. Chemists spent
much of the 18th century evaluating Stahl's
theories before they were finally proved
false by Lavoisier.