N.-l TURE 



[JULV II, 1901 



volume. It is almost superfluous to add that the style in 

 which the essays are written is clear and fluent, and we 

 are sure that even the scientific opponents of the great 

 Sanskrit scholar will be glad to possess in a collected 

 and handy form some of the last writings of a man who 

 has scored his mark broadly and deeply upon the edifice 

 of Indian philology. 



HETEROCYCLIC ORGANIC COMPOUNDS. 

 Die Hcterocyklischen Vcrbiiidungcn der Orgauischen 

 CItemie. By Edgar Wedekind. Pp. iv + 458. 

 (Leipzig: Veit and Co., 1901.) Price 12 marks. 



THE author of the book before us states in his pre- 

 face that his object is to e.\tend those chapters of 

 the elementary treatises on organic chemistry which deal 

 with heterocyclic derivatives, to supply a text-book of 

 the subject for the use of advanced students and the 

 technical chemist, and thus to render unnecessary the 

 possession of exhaustive and expensive text-books. 



But, with the best will in the world, we regretfully come 

 to the conclusion that the work is of very slight practical 

 value ; heterocyclic derivatives are frequently derived 

 from straight chain compounds possessing complex 

 molecules, and the chemist will find himself compelled 

 to refer to one of those works Dr. Wedekind would avoid 

 the use of in order to elucidate the synthesis of the 

 heterocyclic ring. 



One example of this difficulty, which may, indeed, be 

 met with on almost every page of the book, will suffice ; 

 speaking of the methods of formation of osotriazoles, we 

 find given as the second method : " intermolecular 

 separation of the elements of water from the hydrazo- 

 oximes of i : 2-diketones 



R.C=N.NHQH. R.C=Nn 



I -» I >NCoH,." 



R.C=N.OH R.C=N/ 



Now unless the student or technical chemist had made 

 a special study of the hydrazo-oximes he would possess 

 the vaguest idea of their method of formation, and 

 would have to refer to a text-book. A well-known and 

 inexpensive work of this nature ("Organische Chemie," 

 Richter, ninth edition), under the heading ahydrazo- 

 oximes, describes, not only the formation of these bodies, 

 but also, on the same page, their intramolecular con- 

 densation to the heterocyclic ring. 



Dr. Wedekind has adopted an empirical classification 

 which brings substances of most dissimilar constitution 

 under the same heading ; for e.xample, in the group — 

 Hetero-rings containing five members : 



I. Oxygen as member of the ring. 



(i) Single rings with one oxygen, 

 we find the following bodies, which possess slight genetic 

 connection : furfuran, tetramethylene oxide, y-lactones, 

 and anhydrides of the acids of the succinic series (it is 

 true the author announces his intention of passing over 

 reduced and easily resolvable rings, such as anhydrides 

 and lactones, but to be consistent, should not a reduced 

 ring, such as piperidine, be also ruled out of court ?) 



Nor does Dr. Wedekind's system even possess the 



merit of originality ; this system first appeared in the 



seventh (German) edition of Richter's " Organic 



Chemistry," and has been adhered to in subsequent 



NO. 1654, VOL. 64] 



editions ; it was adopted by Bruhl from Anschutz and 

 Schroeter (editor and sectional editor of the above work) 

 in his continuation of the German translation of Roscoe 

 and Schorlemmer's "Organic Chemistry" (vols. vi. 

 and vii.i. 



The genetic or rational system of nomenclature was 

 adopted by Krafit in 1893, and is to be found, further 

 freed from empiricism, in the last instalment of Meyer 

 and Jacobson's " CJrganic Chemistry '' (the group of the 

 polynucleic benzene derivatives, 1901). 



A due sense of the proportionate importance of certain 

 classes of bodies is frequently absent ; thus the very 

 important purine group is dismissed in a few pages as an 

 appendix to the benzopyramidine group, purines being 

 considered as glyoxalinepyramidines. 



For the rest, the book, which contains an enormous 

 amount of information, seems carefully compiled, up-to- 

 date and accurate ; we prefer to find the references at the 

 foot of the page instead of being collected at the end of 

 the first and of the second part ; out of 1475 references 

 there are fifteen to English publications, which, consider- 

 ing the amount of work which has been done in this 

 country on heterocyclic rings, seems scarcely a fair 

 proportion. 



In view of the facts that the ninth edition of \'. von 

 Richter's " Organic Chemistry " (.Anschiitz-Schroeter) 

 has appeared, and that Messrs. Veit and Co. promise 

 the rapid completion of Meyer and Jacobson's admirable 

 handbook, we can only repeat that such books as the 

 one which forms the subject of this notice are completely 

 superfluous. W. T. L. 



OUR BOOK SHELF. 



The Induction Motor. A Short Treatise on its Theory 

 and Design, with numerous E.xperimenial Data and 

 Diagrams. By B. A. Behrend. Pp.105. (New York : 

 The Eleetrical World and Engineer, igoi. 

 Mr. Behrend, in the preface to his book, rather offers 

 an apology for adding one more to the already over- 

 whelming number of books dealing with electricity and 

 its applications. In some cases an apology of this kind 

 is, unfortunately, justified ; but in this instance, in view 

 of the very great importance of the subject from the 

 electrical engineer's point of view and the increasing 

 introduction of polyphase electrical installations, a work 

 on the above subject, written by a writer who, from his 

 continental experience, should know what he is talking 

 about, is to be welcomed. The author's point of view is 

 made clear by a quotation from Prof J. J. Thomson, 

 printed on the title-page: "The absence of analytical 

 difficulties allows attention to be more easily concentrated 

 on the physical aspects of the question . . . than if he 

 merely regarded electrical phenomena through a cloud 

 of analytical symbols " ; and on a first glance at the book, 

 which consists of only 105 pages, one had hoped for a 

 concise and easily comprehensible statement of the sub- 

 ject. This cannot, however, be said to be the case. The 

 book could be very conveniently entitled " A notebook 

 for the designer of induction motors," and to an electrical 

 engineer well versed in polyphase work it would be, with- 

 out doubt, very useful. The reader who does not possess 

 these qualifications will not find it of much value. The 

 author admits this, in that he adds an appendix contain- 

 ing an extract from Gisbert Kapp's " Electric Transmis- 

 sion of Energy," dealing with the elementary theory of 

 the induction motor, and says that after reading this the 

 reader will be better able to understand his own diagrams 

 and deductions. We think, however, that the author 



