Referee's report by Harold Jeffreys, on a paper 'The Royal Society expedition to Montserrat, B.W.I. Final report' by Cecil Frank Powell Sectional committee: Physics Recommended for publication in Philosophical Transactions, in full. Some reference to previous work on amplitudes is needed and the ratio of the velocities of compressional and transverse waves in rubber would perhaps be different from what is described. The impossibility of resolving P and S at short distances could be elaborated on. [Published in Philosophical Transactions A, 1938]. Endorsed on verso as received 2 March 1937. March 1937