# CLAIRAULT (Alexis-Claude)

, a celebrated French mathematician and academician, was born at Paris the 13th of May 1713, and died the 17th of May 1765, at 52 years of age. His father, a teacher of mathematics at Paris, was his sole instructor, teaching him even the letters of the alphabet on the figures of Euclid's Elements, by which he was able to read and write at 4 years of age. By a similar stratagem it was that calculations were rendered samiliar to him. At 9 years of age he put into his hands Guisnée's Application of Algebra to Geometry; at 10 he studied l'Hopital's Conic Sections; and between 12 and 13 he read a memoir to the Academy of Sciences concerning four new Geometrical curves of his own invention. About the same time he laid the first foundation of his work upon curves that have a double curvature, which he finished in 1729, at 16 years of age. He was named Adjoint-Mechanician to the Academy in 1731, at the age of 18, Associate in 1733, and Pensioner in 1738; during his connection with the Academy, he had a great multitude of learned and ingenious communications inserted in their Memoirs, beside several other works which he published separately; the list of which is as follows.

1. On Curves of a Double Curvature; in 1730, 4to.

2. Elements of Geometry; 1741, 8vo.

3. Theory of the Figure of the Earth; 1743, 8vo.

4. Elements of Algebra; 1746, 8vo.

5. Tables of the Moon; 1754, 8vo.

His papers inserted in the Memoirs of the Academy are too numerous to be particularised here; but they may be found from the year 1727, for almost every year till 1762; being upon a variety of subjects, astronomical, mathematical, optical, &c.