REVIEWS 



Textlaooks of Physical Chemistry: Stoichiometry. By Sydney Young, D.Sc, 

 F.R.S. Also an " Introduction to the Study of Physical Chemistry," by 

 Sir William Ramsay, K.C.B., F.R.S., Editor of the Series. [Pp. lxi. + 38i.] 

 London : Longmans, Green & Co. 7s. bd. 



Nearly four years have elapsed since the first of these textbooks was issued. 

 In that first volume the hope was expressed that the others of the series would 

 be ready for the press before the end of 1904. This hope has not been realised ; 

 but so long as slight delay secures excellence of workmanship, and so long as 

 the contents of each volume are brought up to date, one is prepared to cease 

 grumbling and give a hearty welcome to each belated arrival. 



In the case of two of the previous volumes there was just ground for complaint 

 of the excessive bulk and price ; treatises on Spectroscopy and Stereochemistry 

 extending to 500 or 600 pages are really quite beyond the limits of a textbook, 

 and out of proportion to the scale of the earlier volumes of the series. 



It is therefore gratifying to find that Professor Young, notwithstanding the 

 fundamental and extensive character of his subject, has contrived to give an ex- 

 cellent presentation of it within a reasonable compass. In gauging the extent of the 

 ground which he has to cover, it must be remembered that " stoichiometry " means 

 a good deal more nowadays than it once did. Although not a very common 

 word, it is more than a century since it was first used by Richter to denote the 

 determination of the proportions in which substances combine. Subsequently 

 the meaning has been extended to comprehend not only the determination of 

 atomic and molecular weights, but also the study of the general properties of 

 gases, liquids, and solids, the behaviour of mixtures, solubility, the properties 

 of dilute solutions, and other kindred subjects. 



On the relationship between the gaseous and the liquid states, and on cognate 

 problems, Professor Young is especially qualified to write, in virtue of his own 

 extensive and admirable investigations, but in the other parts of the book also 

 the treatment is generally good. . A critical perusal of the two chapters on the 

 determination of atomic weights may be recommended, for much loose thinking 

 on this subject is current even among advanced students. 



As regards the division of the available space among the various sections of 

 stoichiometry, and as regards the arrangement of the chapters, there is some room 

 for criticism. Only tventy-four pages are allotted to the consideration of the 

 properties of dilute solutions— a space which, in view of the part played by dilute 

 solutions in the development of modern physical chemistry, is decidedly inadequate. 

 When this small space is compared with the 130 pages devoted in a previous 

 volume to the subject of steric hindrance it is obvious that the scale of treatment 

 by the different authors of the textbooks has been very far from uniform. 



The chapter on the properties of dilute solutions not only suflfers from undue 

 brevity ; in one respect, at least, it has not been brought up to date. The last 



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