Copy letter from Herbert Rix, to Professor Sylvanus Thompson, Fellow of the Royal Society 'Dear Sir, Lord Rayleigh thinks I had better let you know that there is lost a box of coloured slides belonging to "Lovibond's Tintometer". This is of considerable money value. If it is in this house at all it is probably in the instrument room. Should you in the course of overhauling the apparatus there, come across it, pray be so good as to let me know. Yours faithfully Herbert Rix Asst. Sec. R.S. [Assistant Secretary, Royal Society]'. 21 June 1894