LAPLACE, Pierre Simon, MARours or, French mathematician and astronomer: b. Beaumont-en-Auge (Calvados), 28 March 1749; d.. Paris, 5 March 1827. He studied the higher mathematics at the academy of Beaumont; in 1767 went to Paris and there by the influence of D'Alembert became pro fessor of mathematics in the Ecole Militaire. By his brilliant memoirs on the theory of probability he attracted wide notice and in recognition was elected membre-adjoint (1773) and titular member (1785) of the Academy of Sciences. He was appointed examiner in the royal artillery corps (1784) and professor of analysis at the Normal College (1794); and in 1816, for the elegance of his style in the 'Ex position du Systeme du (1796), was ad. matted to the Academie Franiaise, of which in 1817 he became president. Appointed by Na poleon Minister of the Interior (1799), he was shortly dismissed, being, according to the em peror, °below mediocrity as a minister,° and aiming to ((conduct the government on the prin ciples of the infinitesimal calculus.° He was, however, given a seat in the Senate. became its vice-president and in 1803 chancellor. He also held the post of president of the Bureau of Longitudes and was a member of the com mission for the establishment of the metric system. On the creation of the empire he was
made a count; but he acquiesced in the down fall of Napoleon, and was the recipient of a marquisate at the hands of the monarchy iu 1817.
Nichol called him the °titanic geometer," and he has been styled also attic Newton of France .° Among the more important of his remarkable investigations are the discovery of the inequality in the movements of Jupiter and Saturn; his researches in probabilities (con tained in the (Theorie analytique des proba bilites,' 1812, and the 'Essai philosophique stir les probabilites,) 1814) ; his improvements in the lunar theory, and his theory of the tides. His chief work is the great (Mecanique celeste' (1799-1825), a compendious solution of the problems of physical astronomy, and one of the greatest contributions ever made to science. It was translated into English by Nathaniel Bowditch (q.v.) (1829-39). A collection of Laplace's works in 13 volumes was made by the French government (1878 et seq.). Consult the life 'by Kaufman (Paris 1841), and Arago, 'Biographies of Scientific Men' (in Eng. trans., Boston 1859).