(Philip de la), an eminent French mathematician and astronomer, born at Paris in 1610. His father, who was painter in ordinary to the king, designed him for the same profession; but he devoted himself to mathematical studies, and was nominated together with M. Picard to make the necessary observations for anew map of France by the directions of M. Colbert. In 1683, he was employed in continuing the famous meridian line begun by M. Picard; and was next engaged in constructing those grand aqueducts which were projected by Louis XIV. He died in 1718, after having written a great number of works, besides several occasional papers dispersed in journals, and in memoirs of the Academy of Sciences.