Referee's report by Edmund Clifton Stoner, on a paper 'Magnetic susceptibilities and related properties of rare earth crystals. I' by William George Penny and G J Kynch Sectional committee: Physics Recommended for publication in Proceedings. The paper is a substantial contribution to scientific knowledge but in it's present form, it can only be read and understood by a limited number of specialists. Further explanation is required in parts and the approach could be simplified. [Published in Proceedings of the Royal Society A, 1939]. Endorsed on verso as received 1938. 1938