Lavoisier, Antoine-Laurent de

(1743-1794)

   chemist

   Considered the founder of modern chemistry, Antoine-Laurent de Lavoisier was born in Paris and was educated at the Collège Mazarin. He served as one of the farmers-general and held several other public offices, including those of director of the state gunpowder works (1776), member of a commission during the revolution of 1789 to establish a uniform system of weights and measures (1790), and commissary of the treasury (1791). He also attempted to introduce reforms in the monetary and taxation systems. As one of the farmers-general, he was arrested and executed during the terror. Lavoisier's experiments were among the first quantitative chemical experiments ever performed. He showed that, although matter changes its state in a chemical reaction, the quantity of matter remains the same. These experiments provided evidence for the law of the conversion of matter (Lavoisier's Principle). Lavoisier also investigated the composition of water, and he named the components "oxygen" and "hydrogen." Some of his most important experiments examined the nature of combustion. He demonstrated that burning is a process involving the combination of a substance with oxygen. He also demonstrated the role of oxygen in animal and plant respiration. Lavoisier's explanation of combustion replaced the phlogiston theory, which postulates that flammable materials contain a substance called phlogiston released when they burn. With the chemist claude-louis berthollet and others, Lavoisier devised a chemical nomenclature that is the basis of the modern system (Méthode de nomenclature chimique, 1787). in his Traité élémentaire de chimie (1789), he clarified the concept of an element as a simple substance, and he devised a theory of the formation of chemical compounds from elements. Lavoisier's other writings include Sur la Combustion en general (1777) and Considérations sur la nature des acides (1778). He was named a member of the Academy of Sciences in 1768.