Antoine Lavoisier

Antoine-Laurent de Lavoisier (26 August 1743 – 8 May 1794); ɑ̃ˈtwan lɔˈʁɑ̃ də la.vwaˈzje), the father of modern chemistry, was a French noble prominent in the histories of chemistry and biology. He stated the first version of the law of conservation of mass, recognized and named oxygen (1778) and hydrogen (1783), abolished the phlogiston theory, helped construct the metric system, wrote the first extensive list of elements, and helped to reform chemical nomenclature. He discovered that, although matter may change its form or shape, its mass always remains the same. Thus, for instance, if water is heated to steam, if salt is dissolved in water or if a piece of wood is burned to ashes, the total mass remains unchanged. He was also an investor and administrator of the "Ferme Générale" a private tax collection company; chairman of the board of the Discount Bank (later the Banque de France); 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. At the height of the French Revolution he was accused by Jean-Paul Marat of selling watered-down tobacco, and of other crimes, and was guillotined.