Copy letter from Robert William Frederick Harrison, to F R Low, Editor of "Power" Harrison does not recognise the title Low gives of the paper by B Hopkinson on the cooling effect of cylinder walls, but states that they did recently have a paper by Hopkinson on recording calorimeter for explosions published in Proceedings of the Royal Society, which is available from booksellers for a few shillings per number. The Royal Society's Library Committee is unlikely to agree an exhange with the Power journal, as it deals with the applications of science rather than pure science. 18 July 1907