2022-03-292022-03-291971https://hdl.handle.net/2152.3/11396First-day cover featuring Galileo Galilei with from Mexico on February 27, 1971. An embossed portrait is printed on the envelope and the stamp is a colorized portrait. Two copies of a stamp featuring Renè Descartes who "was noted for his oratory as well as his profound discourses on mathematics and philosophy," from France.First-day cover of Galileo Galilei and two copies of Renè Descartes stamps.Stamp collectingPostage-stamp albumsGalilei, Galileo, 1564-1642Descartes, Renè, 1596-1650Air mail envelopesPhilosophyMathematics