Copy letter from Robert William Frederick Harrison, to T E Davies, Royal College of Science, South Kensington, S.W. With reference to Davies' letter of the previous day, the paper by Professors [John] Perry and [William Edward] Ayrton 'On the Practical Solution of the Most General Problems of Continuous Beams' in the 'Proceedings of the Royal Society' 199, pages 493-505, can be obtained either from the Society's office or from their publishers, Messrs Harrison & Sons, 45 St Martin's Lane, priced two shillings and six. 20 July 1897