H. L. Wells, F. M. Chapman, Edward F. Bigelow, W. F. G., ../../ (1913)
“ Fire, as we usually see it, is the action of air upon hot substances that can burn. It is only one ingredient or part of the air which does this, the oxygen. Usually when things burn, there are hot gases and vapors formed which make the flame. Fire is not a substance, therefore, but an action, or its appearance. ”
