Copy letter from Herbert Rix, to Professor James Alfred Ewing, Fellow of the Royal Society 'Dear Sir, With reference to Dr [John] Hopkinson's paper which was referred to you, there were originally duplicate copies sent by the author. Only one copy was returned from the referees, and the object of this note is to ask whether the other copy is in your hands. Yours faithfully, H Rix Asst. Sec. R.S. [Assistant Secretary, Royal Society]'. 1 July 1889