June i, 191 i] 



NATURE 



445 



always interested in the extension of general pro- 

 cesses from two to three dimensions. 



For those who are studying the subject with little 

 or no external assistance, this is certainly an admir- 

 able text-book. The writer is evidently fully conscious 

 of the kinds of difficulties that beset the inexperienced 

 student. The expository work is excellent through- 

 out, but in particular we may direct attention to the 

 section on the discriminatinc cubic, the chapter on the 

 intersection of conicoids, and the treatment of tor- 

 tuous curves, which is always a serious stumbling- 

 block at a first reading. Easy numerical examples 

 are freely provided throughout the text to illustrate 

 the workinp- of each new idea. We arc particularly 

 glad to see that a fairly complete set of answers has 

 also been supplied. At the end of each chapter there 

 are sets of harder examples, which include some of 

 considerable difficulty, and the book closes with a 

 useful index. 



Within the limits which the author has chosen the 

 volume will be found comprehensive, thoroughly 

 trustworthy, and eminently lucid. Those who have 

 had much to do with higher school work or the junior 

 students at the universities have felt for some time 

 the need of a new text-book on solid geometry. We 

 have no doubt that lecturers and tutors will find this 

 volume most useful for their pupils, and we shall not 

 be surprised if a welcome is extended to it from 

 abroad. 



TRY SIC AL CHEMISTRY. 



Traiti de Chimie gendrale. By Prof. W. Nernst. 

 Ouvrage traduit sur la 6e Edition allemande. By 

 Prof. A. Corvisy. Premiere Partie. Propridt^s 

 g^'ndrales des Corps. Atome et Molecule. Pp. iv + 

 510. (Paris: A. Hermann et Fils, igii.) Price 

 12 francs. 



IN the movement associated with the rapid develop- 

 ment of general chemistry during the last twenty- 

 five years, the apathy displayed by a considerable 

 section of French chemists afTords a striking contrast 

 to the activity and enthusiasm which has marked the 

 progress of physical chemistry in other countries. For 

 this state of rilTairs there can be little doubt that the 

 chief factor responsible is to be found in the influence 

 of the older generation of chemists, whose attitude 

 towards the problem involved in the operation of 

 chemical forces has been determined largely by a 

 patriotic adherence to the doctrines of Berthelot. 

 Signs are not wanting, however, that the resistance, 

 which has been offered to the spread of more rational 

 and modern views, is rapidly decreasing. 



The translation of the sixth edition of Nernst's 

 well-known work cannot fail to accelerate the accept- 

 ance of these views, and the service rendered by the 

 translator in bringing this classical treatise within 

 reach of the average French student of chemistry is 

 no mean one. Since the appearance of the first edition 

 of the work, published in 1893, the book has under- 

 gone many alterations, and by appropriate additions 



NO. 2170, VOL. 86] 



the author has contrived to maintain its character 

 as a thoroughly modern treatise of general chemistry. 



Amongst such changes may be noted a more de- 

 tailed treatment of the molecular theory in its appli- 

 cation to the liquid and gaseous states of aggregation 

 on the basis of the van der Waals's and the reduced 

 equations of condition. Considerable jnodifications 

 have also been made in dealing with the subject of 

 electric conduction, and more particularly with the 

 phenomenon of conduction in gases. The recent rapid 

 progress of knowledge in the domain of colloidal 

 chemistry has also necessitated an extension of the 

 chapter dealing with the colloidal state, and a short 

 section is devoted to the consideration of radio- 

 activity. In this, the author's aim is not so much 

 that of recording the epoch-making discoveries which 

 have been made in recent years, as to show the 

 general bearing of the ideas, which have resulted 

 from these investigations, on the atomic and mole- 

 cular theories. 



As an exposition of the general properties of matter 

 the book occupies a unique position, and the rapid 

 sequence of new editions in the original language is 

 a fitting testimony to the widespread recognition of 

 its intrinsic merits in the country of its origin. 



As in the case of many other German publications, 

 exception must be taken, however, to the comparative 

 neglect of the work of physical chemists in other 

 countries. This is doubtless more or less accidental, 

 but it is a matter to which attention might be given 

 by the author in the event of the issue of further 

 editions or translations. The present translation claims 

 to be a faithful reproduction of the German, and, as 

 such, the translator's task appears to have been car- 

 ried out in a highly commendable manner. 



OUR BOOK SHELF. 

 Elements of Analvtical Geometry. By Prof. G. A. 

 Gibson and Dr. P. Pinkerton. Pp. xxi + 475- 

 (London: Macmillan and Co., Ltd., 1911.) Price 

 75. 6d. 

 It is too often the custom to regard analytical 

 geometry and analytical conies as synonymous terms. 

 Most introductory treatises on Cartesian methods 

 limit their scope to the investigation of properties 

 of curves of the second degree, and it is left to writers 

 on the calculus to supplement this course with a brief 

 mention of the nature and functions of a few higher 

 plane curves. A preliminary course in the use of 

 fundamental formulae is clearly essential, but so soon 

 as facility in expression and interpretation has been 

 acquired, it is both instructive and interesting for the 

 student to realise their application, not merely to the 

 conic, but to curves of a more general character. 

 We therefore welcome the insertion of a chapter, 

 following immediately after a thorough treatment of 

 the straight line and circle, which introduces the 

 student to the conchoid and cissoid simultaneously 

 with the conic. The next sixty pages are devoted to 

 the investigation of the shapes of curves which have 

 simple algebraic equations of the type v=/(x), with 

 special reference to turning values and asymptotic 

 forms. In some respects, simplicity would be secured 

 by a more direct appeal to the methods of the calculus 

 than the authors care to adopt. Such a treatment as 

 is indicated in Mr, Mercer's recent text-book, entitled 



