Copy letter from Herbert Rix, to Professor Arthur Cayley, Fellow of the Royal Society 'Dear Sir, Lord Rayleigh wishes me to ask whether you wish your last memorandum on Mr Walker's paper to be copied before communicating it to the author. He might perhaps recognise your handwriting if the original were sent. I am, yours faithfully, Herbert Rix Asst Sec RS [Assistant Secretary, Royal Society]'. 10 December 1887