Copy letter from Robert William Frederick Harrison, to Dr Hampson, 140 Minories, E.C. 'Soirée Dear Sir, We are very sorry to hear that you cannot arrange to exhibit the working of your apparatus. The Officers feel, with you that the chief interest would lie in its demonstration, and are therefore reluctantly obliged to withdraw the exhibit from the programme. Yours truly, Robt Harrison Asst Sec R.S. [Assistant Secretary, Royal Society]'. 1 May 1896