Copy letter from Herbert Rix, to William Crookes, Fellow of the Royal Society 'Dear Sir, As you have already had permission to take an electro of the cut referred to in your note, I do not think it necessary to obtain permission a second time. I have therefore given instructions to the printers to electrotype the block at once for insertion in your anniversary address. It is never under any circumstances allowed to use the block itself. Yours faithfully, Herbert Rix Asst. Sec. RS [Assistant Secretary, Royal Society]'. 26 April 1889