Referee's report by John Sealy Edward Townsend, on a paper 'The effect of water vapour on diffusion Coefficients and mobilities of ions in air' by J J Nolan and Thomas E Nevin Sectional committee: Physics Recommended for publication in Proceedings or Philosophical Transactions. The author should be consulted to see which he would prefer. [Published in Proceedings of the Royal Society A, 1930]. Endorsed on verso as received 28 January 1930. January 1930