August 5, 1898.] 



SCIENCE. 



167 



The Arrangement of Atoms in Space. By J. H. 

 van't Hoff. Second, Revised and Enlarged 

 Edition. With a Preface by Johannes 

 WiSLECENUS, and an Appendix, Stereochem- 

 istry among Inorganic Substances, by Al- 

 fred Werner. Translated and Edited by 

 Arnold Eiloart. London, New York and 

 Bombay, Longmans, Green & Co. Pp. xi + 

 211. 



In the earlier development of theories with 

 regard to the structure of chemical compounds, 

 chemists were very careful to state that the 

 formulae used were not intended to represent, 

 at all, the actual geometrical positions of the 

 atoms within the molecules. It was with a 

 great deal of scepticism, therefoi-e, that the 

 chemical world received the first attempts at a 

 logical discussion of the arrangement of atoms 

 in space. These attempts were made by van't 

 Hoff and by Le Bel, independently, in 1874. 

 For many years the theory made little head- 

 way and, at most, received some notice in con- 

 nection with the discussion of optically active 

 substances. Gradually, however, the theory 

 proved so useful that the present situation is 

 well summarized in the following words of Pro- 

 fessor Wislecenus from his preface to this book: 

 "The old opposition to the principle has al- 

 most died out ; where it still lives it is directed 

 against the ultimate basis — against the Atomic 

 Hypothesis itself — and does not deny that the 

 doctrine of atomic arrangement in three dimen- 

 sions is a logical and necessary stage, perhaps 

 the final stage, in the chemical theory of atoms. 

 * * * It has already effected to the full all 

 that can be effected by any theory ; for it has 

 brought into organic connection with the funda- 

 mental theories of chemistry facts which were 

 before incomprehensible and apparently iso- 

 lated, and also enabled us to explain them from 

 these theories in the simplest way. By pro- 

 pounding to us new problems, the new theory 

 has stimulated empirical investigations on all 

 sides ; it has caused a vast accumulation of 

 facts, has led to the discovery of new methods 

 of observation, has become amenable to the 

 tests of experiment, and has at the same time 

 started in our science a movement full of signifi- 

 cance — in a certain sense, indeed, a new 

 epoch." 



The present work is a new and thoroughly 

 revised edition of van't Hoff's well-known 

 book. It is especially satisfactory in its discus- 

 sion of stereoisomerism in its relation to opti- 

 cal activity. The consideration of ethylene 

 derivatives and of ring compounds is also 

 sufiiciently full, while the concise treatment 

 of the stereochemistry of nitrogen compounds 

 accords well with the present rather vmsatisfac- 

 tory conditions of the topic. The brief state- 

 ment by Alfred Wei-ner of his views upon the 

 stereoisomerism of certain inorganic compounds 

 is an important and valuable addition. 



The present book is noteworthy for the man- 

 ner in which the fundamental conception is re- 

 duced to the simplest possible expression. All 

 hypotheses which are not absolutely essential are 

 omitted. In this respect the book is in marked 

 contrast with that of Auwers on the same subject. 



In a few cases, and especially for camphor 

 and atropine and their derivatives, structural 

 formulae are given which are, to say the least, 

 very improbable, if not entirely impossible, 

 according to our present knowledge. While 

 questions of optical activity are undoubtedly of 

 great importance in the discussion of possible 

 formulae for these compounds, it seems unfor- 

 tunate that such doubtful formulas should have 

 been used in the consideration of the fundamen- 

 tal principles of asymmetry as connected with 

 optical activity. 



The work of translation has been well done, 

 and the translator, who is an authority on the 

 subject, has added several important notes of 

 his own. W. A. Notes. 



Laboratory Experiments on the Class Reactions 

 and Identification of Organic Substances. By 

 Arthur A. Noyes and Samuel P. Mul- 

 LiKEN. Second, Thoroughly Revised Edi- 

 tion. Easton, Pa., Chemical Publishing Co. 

 Pp. 28. Price, 50 cents. 



This little book may be considered as the 

 elements of qualitative analysis for organic 

 compounds. Because of the enormous number 

 of these compounds the svibject is not suscept- 

 ible of any such set mechanical treatment as is 

 usually given to inorganic qualitative analysis. 

 For this reason it is all the more useful for the 

 purpose of developing thoughtfulness and 



