Sylvestre Francois Lacroix, a French mathematician, born in Paris in 1765, died there, May 25, 1843. He belonged to a poor family, but by his own exertions acquired an education, and became such a proficient in mathematics, that when scarcely 17 he was appointed professor in the marine school at Rochefort. In 1786 he went to Paris, and in 1787 became a professor in the military school. While he occupied this chair, the academy of sciences awarded him a prize of 6,000 livres for a treatise on maritime insurance. He held professorships consecutively in the artillery school, the normal school, the polytechnic school, the Sorbonne, and the college de France. He was among the original members of the institute. In 1796 he began the publication of his elementary Cours de mathematiques, comprising arithmetic, algebra (English translation, Cambridge, Mass., 1818), geometry, and trigonometry, which was for years the best text book of its kind. Among his works are Traite du calcul differentiel et integral (2 vols. 4to, 1797), and treatises on mathematical and physical geography and the teaching of mathematics.