Copy letter from Theodore E James, to A E Ruddoel, 58 & 59 Bread Street, E.C. 'Dear Sirs, Dr Hopkinsons paper could formerly be had in separate form, but is now out of print. You can purchase Part 1, 1886, of the Philosophical Transactions ['Philosophical Transactions of the Royal Society'] (containing the paper), at Messrs Harrison & Sons, 45 St Martin's Lane, W.C. It was published at £1-8-0. Yrs [Yours] faithfully, T E James Clerk, RS [Royal Society]'. 2 September 1891