DARBOUX, JEAN GASTON (1842-1917), French mathe matician, was born at Nimes on Aug. 13, 1842. His father died in 1849, and under the guidance of his mother, and with her encouragement, he was educated at the Ecole Normale, Paris. Pasteur became interested in Darboux, and created a teaching post for him at the Ecole Normale. After acting as assistant to Bertrand in the chair of mathematical physics at the College de France (1866-67) he became successively professor of mathe matics at the lycee Louis le Grand (186 7-7 2) , Maitre de confer ences at the Ecole Normale (1872-73), assistant to the professor of rational mechanics at the Sorbonne (1873-8o), professor of higher geometry at the Sorbonne (188o-89), dean of the faculty of science (1889-9o) and perpetual secretary of the Academy of Science. Darboux, besides being an excellent teacher and a notable mathematician, was also a very capable organizer and the last two posts he held gave him ample scope in this direction. He died in Paris on Feb. 25, 1917.
Practically all his mathematical work was on geometry, his early papers (1864 and 1866) were on orthogonal surfaces; these were followed by a memoir on partial differential equations of the second order (187o), which embodied a new method of integra tion. In his treatise Sur une Classe remarquable des courbes (1873) Darboux developed the theory of the class of surfaces called cyclides. Lecons sur la Theorie generale des surfaces et les applications geometriques du calcul infinitesimal (4 vols., 1887 96) is one of Darboux's most important works; dealing with infin itesimal geometry, it embodies most of his previous research work. In 1898 the publication of Lecons sur les systemes ortho gonaux et les coordonnees curvilignes was commenced. Darboux was the author of a number of papers and memoirs on the approxi mation to functions of very large numbers, on discontinuous func tions and on other subjects.
Darboux held honorary degrees of many foreign universities; he was a foreign member of the Royal Society and in 1916 was awarded the Sylvester Medal.