Copy letter from Herbert Rix, to John Joly, Physical Laboratory, Trinity College, Dublin 'Dear Sir, I am not quite clear whether you consider it necessary to reproduce the photographs [underlined], which you sent with your paper on spark discharge, for publication. Kindly inform me on that point. The two drawings are in hand. Yours faithfully, Herbert Rix Asst Sec RS [Assistant Secretary Royal Society]'. 23 July 1889