REVIEWS 



The Viscosity of Liquids. By A. E. Dunstan and F. B. Thole. [Pp. vi + 

 89, with diagrams.] (London: Longmans, Green & Co., 1914. Price 3J. net.) 



This book is a useful addition to the monographs on Inorganic and Physical 

 Chemistry edited by Prof. Findlay. The text is divided into nine chapters, of 

 which the first is devoted to the " Development of a Working Formula," the next 

 three to a discussion of the methods used in measurements of viscosity. The 

 subsequent chapters deal with liquid mixtures, electrolytic solutions, and colloids, 

 and with the relations which have been found between viscosity and chemical 

 constitution. 



It is unfortunate that the large amount of research which has been carried out 

 in this field has provided little more than a collection of disconnected facts. 

 In the book under review attention is drawn to a number of relationships which 

 have been found to exist between viscosity and chemical constitution, such as 

 the definite influence of certain chemical groups, and to experiments indicating 

 that chemical combination is accompanied by maximum values of the viscosity. 

 However in none of these cases has any attempt been made to give a physical 

 interpretation of the results, though a few hypotheses have been thrown out, such 

 as the statement that the influence of the hydroxyl group in raising viscosity is 

 no doubt intimately connected with the potential quadrivalence of the oxygen 

 atoms inducing association. The viscosity of a series of unsaturated organic 

 compounds is also vaguely referred to the degree of residual affinity in the 

 compounds. 



The discussion of the influence of temperature is limited to the consideration 

 of a number of empirical formulae to which no theoretical basis has been assigned, 

 and no attempt is made to justify the general practice of referring all comparative 

 measurements of viscosity to the values obtained at the boiling-points of 

 the liquids. 



In the chapter dealing with electrolytic solutions, the data have been presented 

 in a form showing the significant relationships which may be expected between 

 viscosity and the condition of the ions in solution, such as their degree of 

 hydration and the extent of molecular association. It is very noteworthy that 

 at the present time no rigid relation has been established between viscosity and 

 any other physical property. 



The disconnected nature of the results in this field render the compiling of 

 a monograph on this subject a task of considerable difficulty. In spite of this, 

 the authors have contrived to write a very readable book, which gives a good idea 

 of the present state of this branch of physical chemistry. J. N. P. 



Intermetallic Compounds. By Dr. Cecil H. Desch. [Pp. vi + 116, with 17 

 figures.] Monographs on Inorganic and Physical Chemistry. (London : 

 Longmans, Green & Co., 1914.) 



Those who know the author's " Metallography " will require no assurance as to 

 the merits of this, its junior partner. The present volume is small, but in it is 



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