The Theory of Valency

Abstract

ALTHOUGH one may be inclined to criticise the inclusion of this volume in Sir William Ramsay's well-known series of text-books of physical chemistry, it is to be heartily welcomed on its own account, for there is no English treatise, and no very recent German one, dealing with the important subject of valency. The author's exposition is careful and thorough, dealing at length with the bearing of the periodic law on valency, and with the numerous, and an some cases fantastic, theories which profess to interpret the facts of chemical combination. Dr. Friend is not in a position to expound any one theory of valency which commands general acceptance; in the present state of our knowledge he can only put before the reader some half-dozen theories—Werner's, Abegg's, Ramsay's, his own, and others—to each of which exception may be taken in one respect or another. The Theory of Valency. By Dr. J. Newton Friend. Pp. xiv+180. (London: Longmans, Green and Co., 1909.) Price 5s. net.