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LXXIIL Notices respecting New Books. 



Outlines of Physical Chemistry. By G. Senteb, Ph.D., B.Sc. 

 London : Methuen & Co. 1909. Price 3s. 6d. 



nPHIS excellent textbook is intended as an elementary introduction 

 -*- to the subject of Physical Chemistry. The subject has now 

 grown so large that it is extremely difficult to cover the whole range 

 in a single small book ; but Mr. Senter has succeeded in covering 

 a large part of it. The parts upon w T hich most stress has been 

 laid are those dealing with the modern theories of solutions, the 

 principles of chemical equilibrium, electrical conductivity, and 

 electromotive force. The picture presented by this simple intro- 

 duction is one of the amazingly rapid development which the 

 subject has undergone. Many of the views given here were only 

 accepted (at any rate by the purely physical school) after very 

 considerable opposition ; and even now are accepted only as 

 working hypotheses. This opposition was by no means unrea- 

 sonable, as will be realized by all those who are watching the more 

 recent modifications which these hypotheses are undergoing. We 

 refer in the main, of course, to the theory of solutions ; and we 

 think we detect the signs of change in the fact that our author does 

 not claim the validity of the ph^sico-cheinical theories of solution 

 (put forward by van't Hon 2 and others) with the same dogmatism 

 that we usually meet with. It is now realized by all that the solvent 

 is not the mere idle medium whose sole function is to provide a 

 space in which the molecules of the solute can move about. Its 

 complete function is still unknown, and sufficient is said here for 

 an elementary volume in regard to rival theories. "We do not 

 doubt that there will be considerable modification of all existing 

 views before many years are out. Meanwhile there are huge 

 groups of phenomena which can all be placed together and co- 

 ordinated on the basis of thermodynamic arguments, which latter 

 are independent of any theory of the mechanism of the processes 

 concerned. If we may indicate a preference, it is that, while not 

 ignoring mechanical theories, chief stress should for the present be 

 laid on those facts and phenomena which can so be coordinated. 

 Since Dr. Senter does lay very considerable stress on this side 

 of the subject, we may wish him all good speed. We do not 

 hesitate in thinking that this book supplies a real want. It is 

 simple, so that the beginner will understand almost all of it ; at 

 the same time it does not shirk difficulties, though it often has to 

 leave them not entirely removed. Lastly, its price is remarkably 

 low, so that a student has no reason to avoid purchasing it. 



