Antoine-Laurent de Lavoisier (August 26, 1743 - May 8, 1794), the father of modern chemistry, was a French nobleman prominent in the histories of chemistry, finance, biology, and economics. He stated the first version of the law of conservation of mass, recognized and named oxygen (1778) and hydrogen (1783), disproved the phlogiston theory, introduced the metric system, wrote the first extensive list of elements, and helped to reform chemical nomenclature. He was also an investor and administrator of the "Ferme Générale" a private tax collection company; chairman of the board of the Discount Bank; and a powerful member of a number of other aristocratic administrative councils. All of these political and economic activities enabled him to fund his scientific research. But because of his prominence in the pre-revolutionary government in France, he was beheaded at the height of the French Revolution.

Some of Lavoisier's most important experiments were in thermodynamics, and in the nature of combustion, or burning. Through these experiments, he demonstrated that burning is a process that involves the combination of a substance with oxygen. He also demonstrated the role of oxygen in metal rusting, as well as its role in animal and plant respiration. Working with Pierre-Simon Laplace, Lavoisier conducted experiments that showed that respiration was essentially a slow combustion of organic material using inhaled oxygen. Lavoisier's explanation of combustion disproved the phlogiston theory, which postulated that materials released a substance called phlogiston when they burned.

Lavoisier also discovered that the 'inflammable air' of Henry Cavendish, which he had termed hydrogen, combined with oxygen to produce a dew, as Joseph Priestley had reported, which appeared to be water. Lavoisier's work was partly based on the work of Priestley. However, he tried to take credit for Priestley's discoveries. This tendency to use the results of others without acknowledgment, then draw conclusions of his own, is said to be characteristic of Lavoisier. In "Sur la combustion en général" and "Considérations Générales sur la Nature des Acides", he demonstrated that the "air" responsible for combustion was also the source of acidity. For more, see Wikipedia, Antoine Lavoisier.