c. 460-c. 370 B.C.

Greek philosopher, best known for his atomic theory, who also contributed to the study of geometry. It was Democritus who first stated that the volume of a cone is one-third that of a cylinder with the same base and height, and that the same relationship exists for a pyramid and prism. Half a century later, Eudoxus of Cnidus (c. 408-c. 355 B.C.) proved this proposition. Among Democritus's mathematical writings were On Numbers, On Geometry, On Tangencies, On Mappings, and On Irrationals. All these works have been lost.