Michel ChaslesDied 18 Dec 1880 at age 87 (born 15 Nov 1793).French mathematician who, independently of the Swiss-German mathematician Jakob Steiner, elaborated the theory of modern projective geometry, the study of the properties of a geometric line or plane figure that remain unchanged when the figure is projected onto a plane from a point not on either the plane or the figure. In his text Traité de géométrie in 1852 Chasles discusses cross ratio, pencils and involutions, all notions which he introduced. Chasles was the victim of a celebrated fraud paying the equivalent of £20,000 for various letters from famous men of science and others which turned out to be forged. |
