Referee's report and letter by Frederic Charles Bartlett, on a paper 'The upper frequency limit for the binaural localization of a pure tone by phase difference' by J W Hughes Sectional committee: Physiology Recommended for publication in Proceedings, although it may be more suitablly published elsewhere. The paper is excellent, clear and concise. However, the author should have pointed out that his results are expected and the part about 'fatigue' is not satisfactory. He is unsure if it should be published in Proceedings and the Committee should decide. Letter states that the paper needs to be supplemented in some way, or else it gives the impression of being concerned with only one point of detail.If the paper was modified to reflect his suggestions, it would be suitable for Proceedings. [Published in Proceedings of the Royal Society B, 1940]. Endorsed on verso as received 9 August 1939. 8 August 1939