Copy letter from Herbert Rix, to Dr Bierens de Haan, Leiden 'Dear Sir, I am sending by this post, registered, the copy of Wallis's letters. I found that I was forced to get a skilled copyist, as the ink was so faded & the writing so antiquated, that it was beyond the powers of an ordinary copyist. It came to over a pound, but I paid only one pound (£1) for it, and I shall be glad if you will refund that sum at your convenience. I am yours truly Herbert Rix Asst. Sec. R.S. [Assistant Secretary, Royal Society]'. 6 January 1894