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NA TURE 



[January 28, 1909 



entering the university he can follow a course which 

 involves the thermodynamics of chemical reactions. 

 This is done, we are told : — 



" Because it furnishes the demonstration of the law 

 of Guldberg and Waage and of the principle of Le 

 Chatelier, which, concurrently with the atomic hvpo- 

 thesis and the hypothesis of Arrhenius, serve as the 

 basis of my teaching. It gives a precise notion of 

 affinity, the primordial cause of all chemical transform- 

 ations, and it affords an opportunity for discussing the 

 significance of the principle of maximum work. 

 Furthermore, I have wished to combat the unfortunate 

 tendency often observed among engineering students, 

 whose studies are largely mathematical, to consider 

 chemistry as an empirical and descriptive science 

 which appeals mainly to the memory." 



In the latter object we should think Prof. Swarts 

 has been successful, and we are only doubtful whether 

 the student may not carry away the impression that 

 chemistry is a branch of mathematics. Although 

 somewhat advanced, according to our notions of an 

 introductory course, the book is clearly written and 

 printed in excellent type. It is also well illustrated, 

 and the purely chemical information seems up to date. 



(2) In writing a text-book of moderate dimensions 

 which shall at the same time embrace the most recent 

 developments of the subject there is a risk of super- 

 ficiality, a risk which the author has not, altogether 

 succeeded in avoiding. Short sections are devoted to 

 the mass law, the phase rule, transition temperatures, 

 electrolytic dissociation, the theory of valency or 

 valence, as Americans call it, induced reactions, col- 

 loids, the new gases of the atmosphere, radio-active 

 elements, the rare earths of the cerium group, &c. 

 The more elementary chemical information has to 

 suffer occasionally in consequence. We would instance 

 the treatment of flame, which is carried no further 

 than that of the most elementary text-book. On the 

 other hand, it must be admitted that the author has 

 produced, if not a suggestive, at least an interesting 

 book, and has managed to collect in a small compass a 

 large amount of information. The appearance of a 

 third edition is a sufficient testimony of public appre- 

 ciation, .-^s proofs of composition we should like to 

 see the electrolysis of water and hydrogen chloride 

 disappear once and for ever from the text-book. The 

 first is untrue, and is usually contradicted in a later part 

 of the book; but if the first is true the second can 

 afford no satisfactory evidence of the composition of 

 hydrogen chloride because water is invariably present. 



We should also like to see consigned to the same 

 limbo of questionable statements Lavoisier's author- 

 ship of the principle of the conservation of mass. We 

 might with equal truth assign to him the statement 

 of the principle of the conservation of energy, since 

 he was the first to attach to the imponderable matter 

 of heat or caloric a real and permanent existence. 

 What are the facts? Simply that matter has for ages 

 been regarded by the majority of philosophers as in- 

 destructible, and Lavoisier did no more than accept 

 the principle and base his experiments upon it. Jean 

 Rey, in his somewhat figurative style, states that 

 " the weight with which each portion of matter is 

 endowed at the cradle will be carried with it to the 

 NO. 2048, VOL. 79] 



grave," whilst Bovle expresses himself still mure 

 clearly : — 



" For it far exceeds the power of merely natural 

 agents (and consequently of the fire) to produce anew 

 so much as one atom of matter which they can but 

 modifie and alter not create, which is so obvious a 

 truth that almost all sects of philosophers have deny'd 

 the power of producing matter to second causes." 



Let us compare this statement with that of Lavoisier 

 (" Elements of Chemistry," vol. i., p. 226, Kerr's 

 translation) : — 



" We may lay it down as an incontestable axiom, 

 that in all the operations of art and nature, nothing 

 is created; an equal quantity of matter exists both 

 before and after the experiment ; the quality and 

 quantity of the elements remain precisely the same, 

 and nothing takes place beyond changes and modifica- 

 tions in the combination of these elements. Upon 

 this principle the whole art of performing chemical 

 experiments depends. We must always suppose an 

 exact equality between the elements of the body ex- 

 amined and those of the products of its analysis." 



But this is nothing more than the axiom laid down 

 by Boyle ! That Lavoisier actually weighed his 

 materials and products scarcely gives him the claim 

 put forward by Prof. Holleman that he first intro- 

 duced the principle of the conservation of mass into 

 chemistry. Nor is Prof. Holleman more correct in 

 saying that Lavoisier " assumed that gravity is an 

 inseparable attribute of all matter." What about the 

 imponderable matter of heat ! 



(3) Those who are acquainted with the many excel- 

 lences of Prof. .Vlexander Smith's " Introduction to 

 General Chemistry " will question the wisdom of pub- 

 lishing an abridgment of it for the use of schools and 

 colleges. For the new volume is an abridgment in 

 the sense that the arrangement, the illustrations, and 

 page after page of the text are taken without modifica- 

 tion from the original. This is unfortunate, because, 

 if the matter is to be simplified for younger stu- 

 dents, it must be expanded as well as curtailed, 

 which is not the case. For example, of all subjects 

 which demand clear and explicit treatment at con- 

 siderable length, that on the measurement of gases 

 should stand among the first. Yet we find the twelve 

 pages forming an excellent chapter on the subject in 

 the original cut down to less than five pages in the 

 abridgment. The same is true of the section on 

 catalysis ; but the danger of this process is perhaps 

 best illustrated on p. 89, where the expression " critical 

 temperature " occurs without, so far as we can ascer- 

 tain, any further explanation, whereas the original 

 volume contains a very lucid account of critical 

 phenomena in general. It seems scarcely worth while 

 to issue at so small a difference in cost a volume so 

 distinctly inferior to the original, which we regard, 

 apart from the introductory chapters, as one of the 

 best books on the subject. 



(4) Little need be said about Dr. Bailey's " Matricu- 

 lation Chemistry." It has long been recognised as a 

 standard work of the " Tutorial " series. A book of 

 such substantial proportions should, we think, carry 

 the student not only well through the matriculation 

 stage, but very considerably beyond it. The book is 

 well arranged and full, almost too full, of information. 



