Augustin Louis Cauchy, a French mathematician, born in Paris, Aug. 21, 1789, died May 23, 1857. Admitted in 1805 to the polytechnic school, he distinguished himself by the solution of difficult problems. He was admitted to the academy in 1816, and about the same time appointed professor of mechanics in the polytechnic school. The journals of the academy and several European mathematical journals contain numerous memoirs from his pen. His attachment to Bourbon legitimacy prevented him from taking the oath of allegiance, by which alone he could retain the public offices which he held in 1830, or accept those offered him on subsequent occasions. In 1848, however, he was appointed to the chair of mathematical astronomy which was then instituted at the Paris university; but refusing to take the oath of allegiance, he relinquished his post in June, 1852. He made contributions to almost every branch of mathematics, but his reputation rests chiefly on his residual and imaginary calculus. Among his numerous works are: Cours d'analyse (Paris, 1821); Lecons sur les applications du calcul infinitesimal a la geometrie (2 vols., 1820-'8); Exercices mathematiques (1826-'9); Sur l'application du calcul de residus (1827); Lecons sur le calcul differential (1829); Memoire sur la dispersion de la lumiere (183G); and Exercices d' analyse et de physique mathematique (3 vols., 1839). His politico-religious writings testify both to his faith in legitimacy in politics, and in Roman Catholicism in religion.

One of his most characteristic works of the kind is his poem Charles V. en Espagne (1834).