Copy letter from Robert William Frederick Harrison, Assistant Secretary of the Royal Society; to Professor [Hugh Longbourne] Callendar, Chairman of the Physics and Chemistry Committee and FRS 'Paper by E.B.R. Prideaux on "The us oif partly neutralised mixtures of acids as hydrion regulators" Professor Donnan reports in favour of this paper being published in Proceedings. Will the Chairman plase say if it should go forward under Standing Order 43?' 19 May 1916