Copy letter from Robert William Frederick Harrison, to Sir Joseph Norman Lockyer, Fellow of the Royal Society Before the Society proceeds with the engraving of the three plates for Lockyer's paper, Harrison would like advice on one or to points. Wonders if they can be slightly reduced as they are presently dangerously large for the 'Proceedings [of the Royal Society]' and wonders if this might be done by reducing the white spaces between the spectra. Presumes Lockyer would like the plates collotyped and that Lockyer could supply the negatives. 24 March 1897