Dervishes

Sect of Mohammedan devotees, not bound by vows. but often celibate. They are fanatical in their worship, acted by an irreconcilable opposition between mind and matter. He devised the method of "Indeterminate Coefficients," also the law of signs for the roots of an equation. His name is attached to a cla of curves, "Cartes i an Ovals," and to the system of co-ordinates in general use. He founded Analytical Geometry by a work pub. 1638, and again 1659, with commentaries by Van Schooten. His works, edited by Victor Cousin, were collected in 11 vols., 1824-26.