Michel Chasles, a French mathematician, born at Epernon, Nov. 15, 1703. After the completion of his studies in 1814 at the polytechnic school of Paris, he removed to Char-tres, where he obtained a professorship in 1825. He subsequently returned to Paris, where in 1841 he was appointed professor of geodosy and machinery in the polytechnic school, and in 1846 of superior geometry, a chair especially established for him in the faculty of sciences. In 1851 he became a member of the academy. In 1867 he reported to that body his possession of alleged autograph letters of Galileo, Pascal, and Newton, containing startling revelations, and claiming for Pascal the merit of Newton's most celebrated discoveries. These letters were part of about 27,000 which Chasles purchased from a M. Irene Lucas for 140,000 francs, including about 2,000 pretended to have been written by Rabelais, and others by Mary Stuart, Shakespeare, Dante, Petrarch, and Julius Ca3sar, and by emperors, poets, saints, and statesmen of various countries and eras. Though these documents were spurious, with the exception of about 100, Chasles, Elic de Beaumont, and Balard regarded the whole of them as genuine, and Charles Dupin insisted upon their being published by the government.

Lucas was sentenced, Feb. 23, 1870, to two years' imprisonment for forgery and fraud. The principal works of Chasles are: Apercu historique sur l'origine et le deve-loppement des methodes en geometric (Paris, 1837; German translation by Sohncke, Halle, 1830); Sur l'attraction des ellijisoides (1837 et seq.); Histoire de l'arithmetique (1843); Sur l'attraction des corps de forme quelconque (1845); Traite de geometric superieure (1852; German translation by Schnuse, Brunswick, 1856); and Traite des sections coniques (1865 et seq.)