Copy letter from Herbert Rix, to Professor Silvanus Phillips Thompson, Fellow of the Royal Society, Morland, Chislett Road, West Hampstead, N.W. 'Dear Professor Thompson, Lord Rayleigh thinks that perhaps you can help Dr Murray by answering the inclosed question. If so, perhaps you will write direct? Or, if you prefer it, send the answer to me. Yours truly, H Rix [Assistant Secretary, Royal Society]'. 7 February 1894