October 5, 1905] 



NA TURE 



to the student of glacial geology, though we wish 

 that references to the original memoirs had been 

 in all cases added. There are, as we have tried to 

 show, many valuable criticisms and suggestions con- 

 tained in the work. Lastly, it will prove a useful 

 intellectual exercise to weigh the author's arguments 

 in the balance. For these reasons we believe that 

 readers who have an e.Ktensive acquaintance with the 

 facts and principles of geology will read the book 

 with profit — and with pleasure. J. E. M. 



VH\SICX\. CHEMISTRY. 

 Thcorcliciil Chemistry. By Prof. Walther Nernst. 

 Revised in accordance with the fourth German 

 edition. Pp. .xxiv + yyi. (London: Macmillan and 

 Co., Lti., 1905.) 15s. net. 



THE fact that three further editions of the German 

 text of Nernst's well known treatise on 

 theoretical chemistry have been called for since the 

 appearance of the original in 1893, affords ample tes- 

 timony to its intrinsic merits. .\n English translation 

 of the first edition by Prof. C. S. Palmer appeared in 

 1S95, and this, until now, has been the only English 

 version. 



During the last ten years much valuable work has 

 been carried out in the province of physical chemistry, 

 and the publishers have recognised the necessity of 

 bringing the English edition up to date. With that 

 object Dr. R. .A. Lehfeldt has translated the whole of 

 the new matter contained in the fourth German 

 edition and has revised certain parts of the original 

 translation. 



It has been the reviewer's experience to hear the 

 original translation adversely commented upon, and 

 it is perhaps to be regretted that the bulk of the old 

 text remains as it was in the first edition. .After 

 careful perusal of the work, it is indeed difficult to 

 suppress the feeling that a better result would have 

 been attained by an entirely new translation of the 

 fourth German edition. 



Two new chapters in the work under review deal 

 with " The .Atomistic Theory of Electricitv " and 

 "The Metallic State." In the first of these an ac- 

 count is given of the electron theory and of the 

 phenomena of ionisation and electric conduction in 

 gases. In the second the nature of the metallic con- 

 dition is discussed on the basis of results which have 

 been obtained by the study of the freezing point 

 curves and of the electrical conductivity of mixtures 

 of metals. These chapters form very interesting 

 reading, although, of course, it has not been possible 

 within the compass of seventeen pages to give more 

 than the briefest outline. 



The space given to electro-chemistry has been ex- 

 tended from 26 to 46 pages, and the exposition of the 

 subject-matter greatly improved. The application of 

 thermodynamics and of the osmotic theory to electro- 

 chemical systems is now treated in separate chapters, 

 and many new observations bearing on the theory of 

 electrolysis have been incorporated. 



It is not possible to mention more than a few of 

 the alterations and additions which have been made 

 NO. 1875, VOL. 72] 



in the te.xt generally. One notes with pleasure that 

 the somewhat- abstruse exposition of energy relation- 

 ships in the introductory chapter has been made more 

 lucid. The discovery of the inert gases of the argon 

 series has led to much discussion of late years in 

 reference to the periodic classification of the elements, 

 and these recent views are summarised in the chapter 

 on the atomic theory. 



Other important new sections deal with Werner's 

 theory of molecular compounds, catalysis, the 

 mechanism of autoxidation processes, tautomerism, 

 and the kinetics of heterogeneous systems. The view 

 that tautomerism is due to the co-existence in dynamic 

 equilibrium of mutually transformable isomeric sub- 

 stances seems to be very probable in the light of re- 

 cent work. In this connection the interesting ob- 

 servations of Hantzsch on the transformation of the 

 tautomeric forms of nitrophenylmethane and similar 

 bodies are recorded, but one looks in vain for any 

 reference to Lowry's investigations on dynamic 

 isomerism. In reference to the kinetics of hetero- 

 geneous systems and the mechanism of chemical 

 change, it is now recognised that many gaseous re- 

 actions, usually regarded as taking place in a single 

 phase, are possibly examples of changes essentially 

 conditioned by phenomena at a boundary surface. The 

 rate at which arsine or phosphine decomposes is in 

 accord with the formula for a unimolecular change, 

 but this agreement really affords no conclusive argu- 

 ment with reference to the mechanism of the change. 

 The measured rate of change has possibly nothing 

 whatever to do with the chemical change involved, 

 but merely with a physical change at the surface of 

 the containing vessel. In a third edition reference 

 should be made to this in the section dealing with the 

 mechanism of reactions on pp. 562-564. 



Of necessity, much new work has had to be left 

 unmentioned in the new edition, but the author is to 

 be congratulated on the large amount of new matter 

 which he has been able to introduce without appre- 

 ciable alteration in the size of the volume. With the 

 issue of this second edition one may confidently 

 anticipate that Nernst's book will still maintain its 

 position as one of the classics of theoretical chemistry. 



H. M. D. 



STOKES'S MATHEMATICAL A.\D PHYSICAL 



PAPERS. 

 Mathematical and Physical Papers by the late Sir 



George Gabriel Stokes, Bart. Aol. v. Pp. xxv 



+ 370. (Cambridge: The L'niversity Press, 1905.) 



Price 15s. 

 T^HE speedy completion of the reprint of Stokes's 

 -•- papers is matter of congratulation to the dis- 

 tinguished editor, to the Cambridge Press, and to all 

 students of mathematical physics. The general char- 

 acter of the contents of this concluding instalment 

 is sufiicientiy described in the following extract from 

 Prof. Larmor's preface : — 



" It will be observed that the present volume repre- 

 sents the period in which Sir George Stokes' scien- 

 tific activities were mainly expended in the work of 

 the Royal Society and of public Scientific Committees, 



