c. 240-c. 180 B.C.

Greek Mathematician

The details of his life are virtually unknown, and Diocles is remembered almost entirely for a fragmentary manuscript entitled On Burning Mirrors. In it he discussed not only the physical problem referred to in the title, but such subjects as cutting sphere with a plane, as well as the famous Delian problem of doubling the cube.

On Burning Mirrors may actually have been a collection of three separate short works, combined under a single title that does not reflect the whole. In any case, the book consisted of 16 geometric propositions, most of which involved conics.

In the first proposition, Diocles put forth the focal property of the parabola, and in propositions 2 and 3 presented the properties of spherical mirrors. The next two propositions show the focus directrix parabola construction, which as with the statement on the focal property of that shape are innovations...