Many of the documents relate to a Korean celestial planisphere given to the Paris Observatory 'by Collin de Plancy, the French Consul in Seoul, who dated it at 1741'. In a letter to M. Destombes of the Observatory, Joseph Needham provides a detailed description of this instrument, explaning that it dates in fact from the early 17th century and that it is described in the 《簡平儀說》 [Chien Phing Yi Shuo / Jian Ping Yi Shuo], written by the Jesuit, Sabbatino de Ursis. (First printed 1611).
There are 2 photographs of the planisphere; a list of Chinese astronomical instruments held at the Observatory; tracing of a jade Pi [璧 /Bi] and related transliteration [by Cheng Te-Khun [鄭德坤 / Zheng Dekun]] and notes; photographs of some of the instruments; 4 letters from M. Destombes of the Observatory; copies of 3 letters from Joseph Needham to Destombes; tracing of Chinese inscriptions on some of the instruments, with comments; a 'Philips' Planisphere showing the Principal Stars Visible for Every Hour in the Year; various illustrations of planispheres; copy of the 《簡平儀說》 [Chien Phing Yi Shuo / Jian Ping Yi Shuo]; copy of a letter from Needham to Dr. Francis Maddison of the Museum of the History of Science, Oxford, about the Korean planisphere; letter of reply from John North of the Museum, on behalf of Maddison.