Photostats of letters from Joseph-Nicéphore Niépce to Claude Niépce, written from St. Loup and Chalon sur Saône, all but two in the years 1816-1817. Much of the material in the letters relates to photography and these have been published in part in Foque's LA VÉRITÉ SUR L'INVENTION DE LA PHOTOGRAPHIE; NICÉPHORE NIÉPCE, SA VIE, SES ESSAIS, SES TRAVAUX (Paris, 1867).