DESCARTES (René). Le Monde, ou le Traité de la Lumière, et autres principaux objets des sens. Paris, Jacques Le Gras, 1664. 3 parts in one small volume in-8, fawn basane, coat of arms in the centre, spine decorated, roulette on the edges, red edges (Binding of the end of the XVIIth century). First edition. Traité de la lumière is one of the last scientific works composed by Descartes in 1632-1633, but was not published until after his death in 1664. Its publisher, Jacques Le Gras, associated the booksellers Nicolas Le Gras, Théodore Girard and Michel Bobin with his privilege. The edition contains the Traité de la lumière (260 pp.) illustrated with numerous woodcut figures in the text, some of which are full-page (folded in the margin); the Discours du mouvement local (31 pp.) and the Discours de la fièvre (30 pp.) follow, in separate pagination. A copy bearing the arms of Paul de Fortia, baron de Baumes et seigneur de Piles (1559-1621), former governor of the château d'If and the islands of Marseille, and his wife Jeanne de Tholon de Sainte-Jalle. "The couple had made a donation to the Jesuit college in Avignon, the proceeds of which were used to purchase prizes; in gratitude, the Jesuits had the Fortia de Piles coat of arms embossed on these volumes" (OHR, 2344). This volume was offered as a prize for physics in 1727, with ex-præmio of the said college on the back cover (student's name scratched out). Corners worn, one headband frayed, small stains on first board, cut repaired at top of title. Guibert, 211.