Copy letter from Robert William Frederick Harrison to Prof P V Bevan, Royal Holloway College, Egham 'Paper on Spectra of Li and Cs. Sir Joseph Larmor wishes me to enquire if you will be agreeable to the plate to above paper being reproduced by half-tone process, similarly to your plates with earlier papers. The only difficulty is that some of the fainter-white lines in the spectra may not show up. We believe however that it is not these but the dark lines which are the important ones - if you agree and will let me know the plate shall go forward at once.' 24 January 1912