Lavoisier, Antoine
la-vwa-ze-a', Antoine (1743-1794), a celebrated French philosopher. He was the son of a wealthy merchant. He became a member of the French Academy of Science. Lavoisier gave the phlogistic or fire material theory its last blow. Among other experiments he roasted tin in a glass retort with a long beak which was closed when the air had expanded. At the end of the roasting the retort and contents showed no change in weight. On breaking the point of the retort beak air rushed in with a hissing sound; the retort and contents showed an increase in weight. On collecting the roasted tin and weighing it he found that the tin had increased in weight during the roasting and that this increase was equal to the increase in weight of retort and contents. He concluded that part of the air in the retort combined with the tin during the roasting process. This and similar experiments overthrew the theory of phlogiston. See article on CHEMISTRY.
Lavoisier took an interest in municipal affairs, gaining a prize while yet a young man for an essay on the best means of street lighting. To prepare this paper he shut himself up in a darkened room for six weeks and experimented with artificial lights. He had an enthusiastic following among the young men of family and scientific tastes, but he does not appear to have been appreciated by the masses. When the French revolution broke out Lavoisier was one of the officials engaged in managing the government tobacco monopoly. He and his colleagues were accused,--it matters little of what,--but in this case, of mixing with the tobacco "water and other ingredients hurtful to the health of the citizens." He asked time to complete some researches, but "The Republic has no need of chemists. The course of justice cannot be suspended," was the reply. May 8, 1794, he was guillotined. Despite the threat of Robespierre, Lavoisier's comrades dared to place a wreath on his grave.
Lavoisier is regarded as the founder of modern chemistry. Besides proving that water can be decomposed into its elements; that oxides are formed by the union of an element with oxygen; and making other important discoveries, he wrote a book on chemistry and was chiefly instrumental in founding a modern system of naming elements and compounds.