Copy letter from Herbert Rix, to The Direct Photo-Engraving Company, 38 Farringdon Street, E.C. 'Your estimate (£7-10-0) for reproducing one "Phil. Trans." [Philosophical Transactions of the Royal Society] plate by Dr. Risien Russell is accepted, and you may put the work in hand. The negatives are at your disposal, if you could send for them'. 3 July 1895