PIERRE SIMON, MARQUIS DE LAPLACE, one of the greatest of mathematicians and astronomers, was born on the 23rd of March 1749, at Beaumont-en-Auge, in the department of Calvados, was for some time a teacher in the military school there, and afterwards went to Paris, where he was appointed a professor in the military school, and was admitted a member of the Academy of Science. He had by this time mastered the whole range of mathematical science, as then known, and had besides, solved several problems, which had for many years defied the attempts of astronomers; and now it occurred to him to devote his mathematical powers to the service of astronomy, and he accordingly commenced to plan the work which afterwards appeared as the "Mecanique Celeste." In political life he was unsuccessful. He was appointed Minister of the Interior by Bonaparte, but was after six months, deposed for incapacity. He continued, however, to receive marks of favor from Napoleon, who on the erection of the imperial throne, made him a count. After the Restoration, Louis XVIII made him a peer and a marquis. He died at Paris on the 5th of March, 1827.

Laplace was gifted with wonderful scientific sagacity; this appears especially in his explanations of certain results of mathematical analysis, formerly looked upon as inexplicable, but which he showed to be the expression of physical phenomena which had hitherto escaped detection. Above all his powers, his wonderful memory shone preeminent. His Mecanique Celeste, and supplements to it, are, next to Newton's Principia, the greatest of astronomical works.

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