Brilliant French mathematician, contemporary of Lagrange and Laplace, born at Toulouse; obtained the professorship of Mathematics in the Military School at Paris, and was elected to the Academy of Sciences in 1783; he was one of the commissioners to determine the length of the metre, and held many posts under the Republic and the Empire; among many works his best known is the "Elements of Geometry" (1794), translated into English by Carlyle (1752-1833).