The phlogiston theory (from the Ancient Greek Ï†Î»Î¿Î³Î¹ÏƒÏ„ÏŒÎ½ phlÅgistÃ³n "burning up", from Ï†Î»ÏŒÎ¾ phlÃ³x "flame"), first stated in 1667 by Johann Joachim Becher, is an obsolete scientific theory that postulated the existence of a fire-like element called "phlogiston", which was contained within combustible bodies and released during combustion. The theory was an attempt to explain processes such as combustion and the rusting of metals, which are now understood as oxidation. (wikipedia)
Actually the phlogiston idea is basically correct. When anything "burns" it is actually dissociating molecules into releasing a mixture of finer subatomic elements generally called plasma which we label flame or fire.