Copy letter from Robert William Frederick Harrison, to Walter Geoffrey Duffield, Physical Laboratory, The University, Manchester The Society is about to proceed with the publication of the 'Philosophical Transactions [of the Royal Society]' on the arc spectra of metals. Has several enquiries regarding the plates for the paper. Discusses resizing and arrangement of plates I to III. Notes there are two cards of spectra which are not referred to the in paper. Negatives of all the photographs would probably be required. Queries the apparently confusing numbering of the plates and figures. Notes a curve diagram figure on page 39 of part two which is not referred to in the text. Wishes to consult Duffield on the above points before the work is put in hand. Asks for a line as soon as possible to avoid delays in publication. 29 August 1907