Referee's report by Alexander Oliver Rankine, on a paper 'The refractive index of gaseous heavy water' by Clive Cuthbertson and Maude Cuthbertson Sectional Committee: Physics Not recommended for publication in the 'Proceedings of the Royal Society of London'. The inherent errors in the method lead to uncertainty, and result in an unconvincing conclusion. Suggests the current paper be withdrawn until the further experiments are complete. [Published in the 'Proceedings of the Royal Society of London'] Endorsed on verso as received 7 December 1934. [December 1934]