CLAUDIUS FRANCIS MILLIET, a mathematician, mechanic, and astronomer, descended from a noble family, and born at Chambery in 1611. His principal performances are an edition of Euclid's Elements of Geometry, in which the unserviceable propositions are rejected, and the uses of those retained annexed; a discourse on fortification, and another on navigation. These, with some other pieces, were collected, first in three volumes folio, and afterwards in four, under the title of Mundus Mathematicus; being indeed a complete course of mathematics. He died in 1678, being then professor of mathematics in the university of Turin.