[René DESCARTES (1596-1650)]. File. L.A.S. from the anthropologist Raoul HARTWEG (1914-1993), September 12, 1958, to Jean-Edmond Weelen; 4 pages in-4 on the letterhead of the Museum of Man. Long letter about Descartes' skull, of which he tells in detail the history from Descartes' death in 1650 to its entry into the Museum in 1821 and then into the Museum of Man. Jean-Edmond WEELEN (1903-1975). Autograph manuscript (incomplete) of his study on "René Descartes, René Frédé et l'édition française des Méditations métaphysiques" (19 p. in-8), and preparatory notes for the writing of this study (ca. 30 p.); plus clippings, and photographs of portraits of Descartes and Frédé.