Copy letter from Robert William Frederick Harrison, Assistant Secretary of the Royal Society; to [Messrs Harrison & Sons] 'Please prepare electros of the following blocks & send with invoice to Messrs E. & F. Spon, Ltd, 57 Haymarket. Royal Society Proceedings. Vol. 74, 1904 p268, fig.1 Royal Society Proceedings. Series A vol. 79, 1907 p.264 - fig. 2 -; p.265 - fig.3 -; p.272 fig. 8; p.273 fig.9;'. 6 June 1917