Referee's report by John Edward Lennard-Jones, on a paper 'The replusive forces between isotopic molecules' by Ronald Percy Bell Sectional Committee: Physics Not recommended for publication in the 'Proceedings of the Royal Society of London'. Has delayed returning the paper as he has doubts about whether the paper should be published or not. The experimental method used is simple and cannot give detailed results, leaving doubt as to the validity of the conclusions. Thinks the paper would be best published elsewhere. [Published in the 'Proceedings of the Royal Society of London'] Endorsed on recto as received 25 November 1939. 24 November 1939