Copy letter from Herbert Rix, to Professor John Henry Poynting, Fellow of the Royal Society 'Dear Sir, Proceedings ['Proceedings of the Royal Society'], nos. 266 & 267 will be sent to you without payment; you are entitled to the completion of your volume. Receipt for your cheque enclosed herewith. Yours faithfully, H Rix Asst. Sec. R.S. [Assistant Secretary, Royal Society]'. 3 May 1889