Copy letter from Robert William Frederick Harrison, to Messrs Harrison & Sons 'When sending your statement about Phil Trans [Philosophical Transactions of the Royal Society] paper used during past year, please add a definite statement about your practice in regard to use or non-use of this paper for authors' copies, proofs, &c. If so used please give us an idea of the proportion per cent that should be allowed on an average for such purposes. RWFH'. 16 October 1907