Unpublished paper, 'The rest masses of the neutron and neutrino' by H O W Richardson Printed proof of a paper in which Richardson attempts to 'deduce the rest masses of the neutron and neutrino [...] by consideration of the process of beta-ray disintegration.' Note reads 'Paper by H O W Richardson set up in page proof, but held up from printing at last moment by the author, and ordered to be placed in the archives of the Society by the Secretaries on 9.XI.39'. Includes a letter dated 7 November 1939. Subject: Physics Received 16 March 1939. Communicated by Arthur Eddington. 1939