Born Sept. 26, 1754, in Angers; died there July 5, 1826. French chemist. Member of the Paris Academy of Sciences (1816).
Until 1777, Proust studied at the University of Paris and was chief apothecary at the Salpêtrière Hospital. From 1777 to 1780 he taught chemistry at the seminary at Vergara in Spain, and from 1780 to 1791 he gave lectures on chemistry in Paris. He then received professorships at the artillery college in Segovia and the University of Madrid (1791–1808).
Proust established the law of definite proportions during the course of a long scientific debate (1801–08) with C. Berthollet. He discovered metal hydroxides and showed that metals can form more than one oxide and one sulfide. Proust isolated glucose from grape juice in 1802 and published his findings in 1806.