La Grange, Joseph-Louis, count de

(1736-1813)

   mathematician

   Born in Turin, italy, where he was educated at the university, Joseph-Louis, count de La Grange was appointed professor of geometry at age 19 and later (1758) founded a society that was to become the Turin Academy of Sciences. In 1766, he was appointed director of the Berlin Academy of Sciences and, in 1786, was invited to Paris by King louis XVI. During the revolution of 1789, he was in charge of the commmission for establishing a new system of weights and measures, to be known as the metric system. After the Revolution, La Grange became a professor at the newly established École normale supérieure, then at the École polytechnique and, under napoléon i, was named to the Senate and made a count. As one of the greatest mathematicians of the 18th century, he created the calculus of variations, worked on a theory of numbers, and systematized the field of differential equations. Among his innovations in astronomy were calculation of the movements of the moon and motions of the planets. His greatest work is Mécanique analytique (1788). La Grange was nominated to the Academy of Sciences in 1772.