Copy letter from Robert William Frederick Harrison, to Richard Threlfall, Fellow of the Royal Society Sending the manuscript and drawings of the paper by Messrs Vonwiller and Mason, for the purpose of preparing a short Meeting Abstract. The delay in sending the manuscript has been occasioned by the necessity of retaining it at the Royal Society so that it might be available for consideration by the Sectional Committee for Physics and Chemistry at their recent meeting [ no enclosures]. 7 February 1907