Copy letter from Robert William Frederick Harrison, Assistant Secretary of the Royal Society; to Messrs Harison & Sons 'Please prepare electros of Figs. as below:- Proc. Roy. Soc. B Vol. 80 Pl. 14, Fig. 6; pl. 15, Fig. 8; Pl. 16, Fig. 10. and send when done, with invoice, to Mr. Edward Arnold, Publisher, 41 Maddox Street, W.' 16 April 1917