Referee's report by Horace Lamb, on a paper 'The origin and growth of ripple-mark' by Phoebe Sarah Hertha Ayrton Sectional Committee: Physics and Chemistry Not recommended for publication in Philosophical Transactions. The experiments are very interesting and important, and with some compression the paper would be excellent for the Proceedings. The author reasons in terms of velocity but viscosity is also important. Considering that the dynamics of much simpler phenomena is only very imperfectly understood, an exact theory cannot be expected and general explanations are all that is possible. This is why Lamb is not at present able to advise publication in the 'Transactions'. From an experimental point of view a good many interesting points seem to be made out; but they are not altogether new. Some reference should be given to Osborne Reynolds' experimental papers on sinuous motion. The differential action of gravity pressure is not clearly recognised[?] and the lines with arrow-heads in figure eight are mysterious. [Published in Proceedings of the Royal Society, 1904]. Endorsed on verso as received 4 June 1904. June 1904