French mathematician and physicist, born at Beaugency, Loiret, on the 12th of November 1746. After spending some years as a clerk in the ministry of finance, he turned to scientific pursuits, and attracted considerable attention by his skilful and elaborate demonstrations of physical experiments. He was the first, in 1783, to employ hydrogen for the inflation of balloons, and about 1787 he anticipated Gay-Lussac’s law of the dilatation of gases with heat, which on that account is sometimes known by his name. In 1785 he was elected to the Academy of Sciences, and subsequently he became professor of physics at the Conservatoire des Arts et Métiers. He died in Paris on the 7th of April 1823. His published papers are chiefly concerned with mathematical topics.