Antoine Laurent Lavoisier
Antoine Laurent Lavoisier, (1743-94). French chemist. He investigated the phenomenon of burning and showed that it did not involve the release of phlogiston, a hypothetical substance, but that during combustion a part of common air, which he named oxygen, was consumed. His discovery of the composition of water, though not original, was the start of quantitative chemical analysis. A farmer-general of taxes, he was guillotined as an enemy of the people during the Revolution.