June 28, 19 17] 



NATURE 



> 1 1 



GENERAL CHEMISTRY. 

 General Chemistry for Colleges. By Prof. 

 A. Smith. Pp. x + 662. Second edition. 

 (London: G. Bell and Sons, Ltd., 1916.) 

 Price 65. 6d. net. 



THE second edition of Prof. Smith's 

 "General Chemistry for Colleges" has 

 been entirely rewritten. It now covers nearly 700 

 pages, and might easily be mistaken for a new 

 edition of the author's well-known "General 

 Inorganic Chemistry." Regarded from this 

 point of view, the book is excellent : a very care- 

 ful scrutiny would be needed to discover any- 

 thing of real value or importance that has been 

 sacrificed in the smaller as compared with the 

 larger book, and the student has good reason to 

 be pleased with a condensation which, after 

 eliminating more than a hundred pages of text, 

 has left him with a book that still covers 

 everything that was essential in the original 

 syllabus. 



As the title implies, the book is primarily one 

 for first-year college students, and not for 

 schools. A clever schoolboy could, of course, 

 master its contents; but so many "advanced" 

 subjects are referred to, in an abbreviated form, 

 that he would lose much of the benefit of the 

 change of atmosphere which should take place on 

 passing from school to college. The introduc- 

 tion is, however, so much superior in its method 

 of treatment to that of the larger volume that 

 the reader is left with a desire to see it expanded 

 and used as part of a simple introductory text- 

 book. 



The author is a whole-hearted ionist and makes 

 the fullest possible use of the theory of electro- 

 lytic dissociation. In a footnote on p. 217 he 

 promises that "the objection that separate atoms 

 of sodium could not remain free in water will be 

 disposed of later"; but it is doubtful whether 

 the ghosts of the separate sodium atoms can be 

 finally laid to rest by the somewhat unconvincing 

 Incantation on pp. 234-35, which does not differ 

 essentially from that used ten years ago in the 

 larger book. This was based, then as now, upon 

 the original recommendation of Ostwald that the 

 ghost should be laid by an incessant chanting of 

 the blessed word "allotropy. " The objection is, 

 however, a real one, and is not met by the mere 

 assertion that "metallic sodium and ionic sodium 

 are, simply, different substances," or the implica- 

 tion that sodium and chlorine ions become or re- 

 main separate in aqueous solutions in virtue of the 

 fact that the atoms are provided with equal and 

 opposite electrical charges. The more active 

 part now assigned to the solvent will, no doubt, 

 [ make it easier in future editions to meet the 

 I objections put forward by the student, or occa- 

 sionally by the conscience of the teacher. 

 j The whole volume bears the impress of the 

 wide range of knowledge and the gift of clear 

 exposition which belong to the author, and it will 

 be widely used and read both by teachers and by 

 students of chemistrv. 



T. M. L. 



UUK bUUKSHELF. 

 Diderot's Early Philosophical Works. Translated 

 and edited by Margaret Jourdain. Pp. v + 246. 

 (Chicago and London : The Open Court 

 Publishing Co., 1916.) Price 45. 6d. net. 

 All who are interested in the movement of 

 thought which found its expression in the great 

 French Encyclopedic will welcome this transla- 

 tion of some of Diderot's minor philosophical 

 writings. It* can scarcely be said that they show 

 much profundity or definiteness of purpose. 

 They were rather "works of occasion " — short 

 pieces thrown off at short notice — mainly with the 

 purpose of filling the author's purse when money, 

 as happened so often, was running short with 

 him. Nevertheless, they give us a pleasing 

 insight into Diderot's eager and inquiring spirit, 

 and his impatience with the religious bigotry 

 which was the deadly foe of all free and honest 

 inquiry. The main philosophical point treated in 

 the volume is the relation between mental 

 development and sensuous endowment, a point on 

 which some diversity of opinion is still main- 

 tained. His conclusion is that "the state of our 

 organs and our senses has a great influence upon 

 our metaphysics and our morality " ; and he 

 shows in some detail in what directions 

 this influence is exerted. Tp most modern 

 psychologists Diderot's principle will seem so 

 manifestly true as scarcely to admit of discussion. 

 Nevertheless, the principle has been called into 

 question recently by the New Realists, who 

 argue that the human mind is in immediate con- 

 tact with objective truth. For the confutation of 

 such views Diderot's acute observations upon a 

 blind man and a deaf-mute of his acquaintance 

 are not without value at the present time. 

 Elementary Physics for Engineers : An Ele- 

 mentary Text Book for First Year Students 

 taking an Engineering Cotirse in a Technical 

 Institution. By J. Paley Yorke. Pp. viii+165. 

 (Cambridge : At the University Press, 1916.) 

 Price 45. net. ' 



The ground covered by this text-book comprises 

 the fundamental properties of solids, liquids, and 

 gases ; force, work, and energy ; and the ele- 

 mentary principles of heat, including a chapter 

 on the mechanical equivalent of heat and the 

 fundamentals of the heat engine. The author 

 in his preface states that he has "attempted to 

 present some essential facts of elementary physics 

 as briefly and straightforwardly as possible, with- 

 out any pedantry or insistence on details of no 

 practical importance." While the book contains 

 nothing novel, .the matter is readable and the 

 statements are clear and concise. Formulae and 

 mathematical equations have been avoided to a 

 large extent. There is little in the text to make 

 it peculiarly applicable to engineering students, 

 and compared with some introductory books of 

 physics which have appeared in recent years, the 

 treatment is somewhat sparse. A few chapters 

 are provided with numerical exercises, but no 

 answers are appended. The book is expensive 

 considering the amount of matter it contains. 



