Copy letter from Robert William Frederick Harrison, to Messrs Harrison & Sons, 46 St Martin's Lane 'Mr S. Bidwell:- "Recurrent Images following Visual Suppressions", Roy. Soc. Proc. [Proceedings of the Royal Society], Vol. 56, figs. 1 and 3 (pp. 135 & 143) ditto - "Subjective Colour Phenomena", Roy. Soc. Proc., vol. 60, fig. on p. 369 Please make cliches of the illustrations noted above and send them, together with your account for the same, to Messr Swan, Sounenschein & Company, Ltd, Paternoster Square, E.C.'. 20 April 1899