Copy letter from Herbert Rix, to Professor Joseph John Thomson, Fellow of the Royal Society 'Dear Sir, Will you kindly let us know by return of post whether any addition or alteration is to be made in your paper read yesterday? We shall be waiting to put the proof into pages and must therefore beg you to answer this query without delay. Yours faithfully, H Rix Asst. Sec. R.S. [Assistant Secretary, Royal Society]'. 3 May 1889