This section contains papers of individual members of the Cambridge Philosophical Society and other scientists which have been found amongst the official archives of the Society or deposited with the Society. They comprise chiefly a miscellany of papers and photographs relating to Sir Joseph Larmor, President of CPS 1898-1900. They also include nine letters, 1800-1801, sent by Thomas Young (1773-1829) to W H Wollaston relating to research and experiments on dispersion of crystalline.