OO' 



NATURE 



[November 26, 19 14 



one who is himself one of the pioneers in 

 its development. 



(2) The bulky volume before us represents 

 vol. i. of a Text-book of Physical Chemistry to 

 be completed in Tour volumes. The author, Dr. 

 Karl Jellinek, has indeed no lig'ht task before 

 him in thus undertaking a work which is intended 

 to be an Ostwald Lehrbuch brought up to date, 

 and written in even greater detail than its proto- 

 type. Dr. Jellinek 's repute, however, as an in- 

 vestigator and a writer — it seems only the other 

 day that a large and very valuable work on a 

 branch of physical chemistry appeared from his 

 pen — entitles us to expect that the present book 

 when completed will succeed in fulfilling the 

 author's expectations. As is stated in the preface, 

 stress is laid (though not unduly) upon the 

 physical aspect of the subject, and the fact that 

 two large volumes are to be devoted to the con- 

 sideration of states of matter (in the widest sense) 

 is evidence of this. 



Vol. i commences with a very full account of 

 literature sources (text-books of all kinds and 

 journals) this being followed by an introductory 

 chapter dealing with the principles of the kinetic 

 theory and thermodynamics. Next comes the 

 subject matter proper, beginning first with an 

 account of the gaseous state (do. 160—431), 

 transition from gaseous to liquid (pp. 432-468), 

 arid the liquid state itself (pp. 469-711). In 

 vol. iiv, which is promised shortly, the liquid state 

 will be still further considered, and after that the 

 solid state and dilute solutions. As illustrating 

 the extent of detail one may quote the table of 

 contents of the principal chapter included in the 

 first subsection (dilute gases) of the section deal- 

 ing with the gaseous state in general, viz., the 

 Maxwell distribution law, rigid deduction of the 

 gas law, degrees of freedom, rotation of gas 

 molecules, vibration of atoms in gas molecules, 

 law of equipartition of energy between degrees of 

 freedom inside a molecule, theory of the specific 

 heat of dilute gases. The liquid state is con- 

 sidered in equal detail. • A book written authori- 

 tatively as this undoubtedly is, and on this scale 

 of minuteness, is bound to become an indispens- 

 able work of reference for all physical chemists. 



(3) Dr. Jacques's monograph on complex ions in 

 aqueous solution is an eminently useful publica- 

 tion. Five chapters are devoted to the principal 

 methods of detecting and determining complexes, 

 viz., the chemical method, distribution method, 

 ionic migration method, solubility method, and 

 e.m.f. method. The remaining chapters deal 

 with applications of these methods to various 

 cases, notably the complex mercury salts, 

 ammoniacal solutions of metallic salts, salts of 



NO. 2352, VOL. 94.] 



cobalt and copper (including Fehling's solution), 

 equilibrium between metallic ions at different 

 degrees of oxidation, polyiodides and sulphides 

 (the latter being particularly well treated). The 

 appendix contains a brief account of the hydrate 

 theory and a general scheme for treating com- 

 plexes theoretically. Great stress is laid upon 

 the significance of equilibrium constants and their 

 numerical evaluation. The book can be warmly 

 recommended. W. C. McC. L. 



OVR BOOKSHELF. 



Agriculture in the Tropics. An Elementary 

 Treatise. By Dr. J. C. Willis. Second edition, 

 revised. Pp. xvi + 223. (Cambridge Univer- 

 sity Press, 19 1 4.) Price gs. net. 

 Agriculture resolves itself mainly into a com- 

 bination of the four factors, crops, soil, labour, 

 and climate. Of these, in tropical countries crops 

 are quite the most interesting on account of their 

 diversity and high economic importance. There 

 is therefore ample justification for the large 

 amount of space — nearly half the volume — devoted 

 to descriptions of the principal agricultural pro- 

 ducts ; even then it is only possible to present 

 general outlines of cultivation and preparation. 

 The author draws largely upon his long and varied 

 experience in Ceylon, also upon his personal know- 

 ledge of agriculture in Malaya and India. Soil 

 problems do not receive much discussion ; there 

 is, for instance, little or no reference to modern 

 soil science and we should have expected a fuller 

 account of the practice and details of green manur- 

 ing. The labour factor, on the other hand, 

 especially peasant agriculture, is discussed very 

 fully in the last seventy pages, with the object of 

 describing native methods and considering how 

 their efficiency may be increased. There is much 

 soundness in the general opinions enunciated that 

 before improvements are attempted, due regard 

 must be had to the peasants' environment and 

 scruples. Co-operative seed stores and education 

 by school-gardens are advocated as the most 

 hopeful remedial measures. 



The value of the book lies largely in the original 

 source and nature of the information supplied, 

 based as it is upon intimate knowledge gained by 

 many years' administration as director of the 

 Botanic Gardens in Ceylon. The first edition of 

 the book was published nearly five years ago. 



Chemical Technology and Analysis of Oils, Fats, 

 and IVa.xes. By Dr. J. Lewkowitsch. Fifth 

 edition, entirely re-written and enlarged. Vol. ii. 

 Pp. xiv + 944. (London : Macmillan and Co. , 

 Ltd., 1914.) Price 255. net. 

 The second volume of this well-known work deals 

 with the commercial preparation of the raw 

 materials used in the oil, fat, and wax industries, 

 and with the methods of preparing and examining 

 the individual oils, fats, and waxes. For the fifth 

 edition a competent editor appears to have been 

 found in Mr. G. H. Warburton, who was as- 

 sociated with the late Dr. Lewkowitsch 's ana- 



