The documents include notes from relevant publications; part of a letter from J. R. Partington of Cambridge, on literature relevant to the subject, 18 January 1959; letter from Tony [?] Waddington of Gonville and Caius College, Cambridge, about ionic bonds, 27 November 1959; Ho Peng-Yoke's typed notes on the 'Chin Pi Wu Hsiang Lei Tshan Thung Chhi [金碧五相類參同契 / Jin Bi Wu Xiang Lei Can Tong Qi]', 5 May 1958; typescript draft pages from the paper marked 'omitted from Vol 5'.