December 28, 1899 



NATURE 



199 



I 



wet, proposed from time to time by different authorities, 

 are here discussed, and indicate how much more 

 scientific most metallurgical processes are becoming. 



The last part of the book deals with the highly im- 

 portant subject of desilverisation, and is written in no 

 way inferior to the preceding pages. Altogether the 

 author has succeeded in producing a trustworthy and 

 fairly comprehensive treatise on the metallurgy of lead, 

 and we trust his enterprise may be rewarded by a 

 deservedly large sale. 



OUR BOOK SHELF. 



Zur Stereochemie des fi'mfwertigen Stickstoffes mit 

 besonderer Beriicksichii^ung des asymmeirichen 

 Stickstoffes in der aromatischen Reihe. By Edgar 

 Wedekind. Pp. 126. (Leipzig : Veit, 1899.) 

 Although nearly fifty years have passed since Hofmann 

 succeeded in preparing methylethylamylphenylammonium 

 chloride— a compound in which the nitrogen atom is 

 directly united with five different groups or atoms — very 

 little progress has been made with the study of the 

 stereochemistry of pentavalent nitrogen. It is true, no 

 doubt, that the first and the most important step in 

 advance was made nearly nine years ago by Le Bel, 

 who succeeded in preparing an optically active liquid 

 from a solution of methylethylpropylisobutylammonium 

 chloride, but until quite recently, when Pope accomplished 

 the resolution into its optically active isomerides of 

 Wedekind's benzylphenylallylmethylammonium iodide, 

 Le Bel's work afforded the only evidence which we had 

 of optical activity due to pentavalent nitrogen. The 

 number of known compounds which contain such an 

 asymmetric nitrogen atom, and which might possibly be 

 resolved into optically active components, was also 

 comparatively limited. 



In these circumstances it might seem a little premature 

 to write a book on the stereochemistry of pentavalent 

 nitrogen, since the facts to be dealt with are few in 

 number, and the theories which have been advanced to 

 explain them — although nearly as numerous as the facts 

 themselves — still require a groundwork of experimental 

 confirmation. 



This difficulty of the lack of material no doubt forced 

 itself upon the author, whose book is not merely an 

 historical review of our present knowledge of the stereo- 

 chemistry of pentavalent nitrogen ; this portion of his 

 subject is, in fact, disposed of within the limits of the 

 first seventeen pages, and by far the largest part (ninety- 

 five pages) of the book consists of an account of the work 

 which the author himself has published during the 

 current year in the Berichte ; the remaining thirteen 

 pages are devoted ;to a discussion of the theoretical 

 conclusions to be drawn from the results of his ex- 

 periments. 



As the discussion or criticism of the author's inves- 

 tigations—interesting and important though they are — 

 is a task which does not lie within the scope of this 

 review, little remains to be said except that the whole 

 book is written in much the same way as if it were a 

 paper intended for publication in Liebig's Attnalen; 

 consequently it contains a great many experimental 

 details, including even the results of many analyses, and 

 this rather detracts from its value as a literary effort. 

 Those, however, who take a particular interest in the 

 stereochemistry of pentavalent nitrogen will certainly 

 welcome the book, and principally on account of its 

 historical survey and theoretical conclusions, for here 

 they will find the scattered literature of the subject con- 

 veniently collected and discussed in the light of the 

 authors own important observations. F. S. K. 



NO. 1574, VOL. 61] 



Handbook of Metallurgy. By Dr. Carl Schnabel. Trans- 

 lated by Henry Louis. iTwo vols. Vol. i. Pp. xvi-hSyi ; 

 Vol. ii. Pp. xiv-l- 732 ; 927 Figures in the text. (London : 

 Macmillan and Co., Ltd. 1898.) 

 Bergrath Dr. Carl Schnabf.l is professor of 

 metallurgy and chemical technology at the RoyaJ 

 Academy of Mines at Clausthal, and his work has 

 long enjoyed a well-deserved reputation. Prof. Henry 

 Louis, who translates it, points out that it is a curious 

 fact that there does not exist in the English language a 

 single complete treatise on metallurgy. Dr. Percy's 

 treatises remain only splendid fragments. Dr. C. 

 Schnabel's object has been to give a complete account 

 of the metallurgical treatment of all the metals ordinarily 

 employed, together with all the recent improvements in 

 the art. The two volumes before us are, however,, 

 incomplete, as neither they nor the original work deal 

 with the vast section of metallurgy which includes iron 

 i and steel. 



I Prof. Louis modestly says that his chief object ha& 

 I been to present a faithful interpretation of the original, 

 I In this he has admirably succeeded. With the full 

 consent of Dr. Schnabel, the translator has intro- 

 1 duced brief rules of any new processes, or improve- 

 ments on old ones, that have been brought opt since 

 the German original was produced. It is a pity, there- 

 fore, that the additions made by Prof. Louis are 

 not distinguishable from the rest of the text. In a com- 

 pressed work of this kind space is, of course, valuable ; 

 but it appears to have been in more than one case 

 unequally allotted. The Augustin process, for instance, 

 is now but little used, and is, in fact, nearly obsolete, but 

 it has ten pages devoted to it, while the cyanide process 

 for the extraction of gold from " tailings," which is now 

 the most important wet process in the whole range of 

 metallurgy, has only thirteen pages. The wet process 

 for extracting copper, which does admit of brief state- 

 ment, has no less than forty-nine pages. Many of the 

 illustrations, from their freshness and originality, will be 

 a great boon to students. Iq a second edition it would, 

 be well to devote more care to the illustrations ; at 

 present, though they give a good general idea of the 

 processes or machines they illustrate, they are seldom 

 drawn to scale. The writer of this notice has found 

 general diagrammatic schemes of processes to be of great 

 value to students, and some might well have been in- 

 troduced into the present work. The sections devoted 

 to the metallurgy of ^inc and of aluminium may be 

 mentioned as, considering the size of the volum«, being 

 singularly complete and conscientious. Viewed as a 

 whole, the book is very accurate and trustworthy, and in 

 welcoming this addition to metallurgical literature Prof 

 Louis is to be congratulated on the translation. 



W. C. Roberts-Austen. 



La Philosophie Naturelle. By Dr. W. Nicati. Pp.xi-f 



308. (Paris: Giard and Bri^re, 1900.) 

 Dr. Nicati has, it seems, published books on medicine, 

 on physiology proper, and on psychology. A sense of 

 incompleteness has led him at last to make a raid upon' 

 philosophy. 



An uncompromisingly positive mind, which does its 

 own thinking en amateur^ is rarely uninteresting. And 

 Dr. Nicati has ideas upon Rabelais and Zola, upon art 

 and politics in general, on immortality and evolution, on 

 the ultimate formulae for matter and life. His art- 

 criticisms and his political discourses with a socialist 

 leaning are often readable and sometimes suggestive. 

 A reduction of the idea of responsibility to causation 

 does not lack ingenuity. Unfortunately, any further 

 worth in the book it is impossible to discover, save as it 

 reveals the. writer^s very abnormal psychosis. " Archi- 

 tectonic" faculty united with incoherence, naivety mostly 



