June 15, 1917] 



SCIENCE 



615 



SCIENTIFIC BOOKS 



Theoretical Chemistry. By Walter Neenst. 

 Trans, from revised seventh German edi- 

 tion by H. T. TiZARD. New York: The 

 Macmillan Company, 1916. 22X15 c™-! 

 pp. xix + 853. Price, $5.00. 

 This is a translation of the seventh German 

 edition and as such is welcome. It would 

 have been more welcome, however, if the pub- 

 lisher and the translator had been courageous 

 enough and enterprising enough to have issued 

 the volume some years ago. As it is, every- 

 thing in the book is at least five years old 

 and, in addition, the translator says : " The 

 character of the work is slowly changing, 

 since it is no longer possible in a book of this 

 size to describe fully all the modern develop- 

 ments of theoretical chemistry. The new 

 matter in this edition is therefore concerned 

 mainly with Nernst's own researches. For 

 example, there is a very interesting and clear 

 account of the modem theory of solids, but, 

 on the other hand, practically no mention of 

 the recent advances in radio-activity and the 

 atomic theory. These inevitable restrictions 

 will hardly detract from the value of the 

 book." 



This is certainly a very tactful way of say- 

 ing that Nernst is not willing to take the 

 trouble to revise any parts of the book except 

 those dealing with his own researches. In 

 spite of the impossibility of describing fully 

 the modern developments the translator has 

 induced Professor Tutton to bring up to date 

 all sections in the book dealing with crystal- 

 lography. 



In looking over a book like this, one is 

 struck with passages which would have escaped 

 notice three years ago. On p. 156 Nernst de- 

 duces that the osmotic pressure of a substance 

 in mixed solvents follows the gas laws. He 

 states that the resulting formula was verified 

 satisfactorily by EolofF and then points out 

 that the addition of potassium chloride to 

 aqueous acetic acid may raise the partial 

 pressure of the acetic acid. Most of us be- 

 lieve in some things which we know are not 

 so; but it takes a special type of mind to 



claim that we have proved a thing in the 

 same breath that we mention facts which dis- 

 prove it. The case is not so striking on p. Y07 

 where ISTernst formulates the generalization 

 that if two phases are in equilibrium with a 

 third phase at a certain temperature with re- 

 spect to a certain definite reaction, they are 

 then in equilibrium with each other at the 

 same temperature and with respect to the 

 same temperature. This differs from the pre- 

 ceding case because no data are given to show 

 the inaccuracy of the theorem. N'ernst knows 

 as well as anybody that an aqueous solution 

 saturated with respect to sodium chloride is 

 not in equilibrium with an alcoholic solution 

 saturated with respect to sodium chloride at 

 the same temperature; but the glamour of 

 the phrase is upon him and he does not 

 analyze it to see that what he has said is not 

 the same as that two things which are equal 

 to the same thing are equal to each other, 

 though it may sound like that. This curious 

 mixture of keenness and self-delusion is no 

 longer an isolated phenomenon. We now 

 know that it is a national weakness. 



On p. 570 Nernst is quite willing to state 

 that methyl orange is a basic indicator and 

 that the acid function of methyl orange is 

 unimportant as regards change of color; but 

 he will not mention the fact that Ostwald 

 holds an entirely different view. The people 

 who read Ostwald's books also never learn that 

 anybody questions the opposite view. It 

 would be incompatible with the dignity of 

 either to admit that he was wrong. Con- 

 sequently the student who reads one set of 

 text-books learns one group of facts as un- 

 questioned, while he who reads another set of 

 text-books learns another group of facts with- 

 out any suspicion that these things are not 

 accepted universally. Incidentally, it might 

 be mentioned that Kahlenberg's name does not 

 appear anywhere in the book and that there 

 is no reference anywhere to any of the ob- 

 jections raised by Kahlenberg. 



While one may object seriously to the order 

 in which the subject is presented and to the 

 spirit in which the book is written, there is 

 no gainsaying the fact that Nernst is an ex- 



