November 17, 1923] 



NA TURE 



717 





new illustrations are so easily distinguished from the 

 old by the rougher way of reproduction. The spectro- 

 r^copic sections have not received a similar revision, and 

 do not therefore give a correct impression of the modern 

 position of the subject. Thus the apparatus " best 

 suited to ordinary chemical purposes " is still apparently 

 that of Bunsen, and his recommendations for mapping 

 >pectra are retained. Again, modem work on spectral 

 series will obviously occupy an important position in 

 the next edition, but is very barely touched upon in 

 the present issue. The descriptive chemistry is, how- 

 ever, as good as ever, and the new edition can be 

 heartily commended as one of the best available books 

 on this aspect of the science. 



(2) Mr. Evans's four volumes on " Metals and 

 Metallic Compounds " cover a few pages less than the 

 two parts of vol. ii. of Roscoe. He has the advantage 

 of starting de novo and has made free use of this liberty 

 by developing fully the chemical points that are of 

 special interest to a metallurgist. The book is, how- 

 ever, definitely a chemical rather than a metallurgical 

 treatise, since the compounds of the metals are de- 

 scribed as fully as the elements themselves. To one 

 who is interested in the broader aspects of the science, 

 it is nevertheless refreshing to find a chapter of the 

 introduction given up to geo-chemistry. This intro- 

 duction is followed by chapters on metallography and 

 electro-chemistrv. wliich romplcte the first of the four 

 volumes. 



The systematic description of the individual metals 

 md their compounds in the remaining three volumes 



very wisely based upon the long periods rather than 



the short periods of Mendeleef's classification. In this 



way the natural sequence of alkalis, alkaline earths, 



md earths (rare or otherwise) is preserved, while 



upper is grouped with the heavy metals to which it 



is closely allied. The " eighth group " metals occupy 



\ le third and smallest volume of the series, while the 



-icond and fourth volumes deal with the elements 



which occur in the earlier and later octaves of the long 



periods, together with their obvious homologues in the 



two short periods. Throughout these volumes the 



impression is maintained that the author is a geo- 



hemist and a metallurgist as well as a chemist, and 



lat he has an up-to-date knowledge of modem 



chnical operations as well as of pure chemical science. 

 I is references to technical and semi-techniciU literature 

 re likely to prove of special value, since, although 

 Hterature of this kind may be of relatively transitory 

 (iportance, it is much less accessible to the ordinary 

 iiemical student than the literature of pure chemistry, 

 to which existing text-books form a sufficient guide. 



In view of its special characteristics, Mr. Evans's 

 treatise does not enter into direct competition with 



NO. 2820, VOL. I 12] 



any other work on chemistry, at least in the English 

 language. It will probably appeal in a special way to 

 chemical students with a leaning towards the practical 

 side of the subject, to metallurgists and to engineers ; 

 but it will also serve as a work of reference by means 

 of which chemists in general may trace out items of 

 interest which are not noticed in books of a more 

 conventional type. It can therefore be highly com- 

 mended as an original work of more than average 

 merit, on the prompt completion of which the author 

 may be congratulated. 



Alpine Tectonics and other Problems. 



(i) Die Grundlagen der alpinen Tektonik. Von Fr. 

 Heritsch. Pp. v + 259. (Berlin: Gebriider Born- 

 traeger, 1923.) 95. (>d. 



(2) Geologic von Wiirttemberg nebst Hohenzollern. Von 

 Prof. Dr. E. Hennig. Erste Lieferung. (Handbuch 



• der Geologie und Bodenschatze Deutschlands.) Pp. 

 iii + 216. (Berhn : Gebriider Borntraeger, 1922.) 

 2>s. 2d. 



(3) GrundzUge einer vergleichenden Seenkiinde. By Prof. 

 Dr. W. Halbfass. Pp. viii -f 354. (Berlin : Gebriider 

 Borntraeger, 1923.) 155. 3<f. 



(4) Geotnorphology of New Zealand. By Prof. C. A. 

 Cotton. Part i . Systematic : an Introduction to 

 the Study of Land-forms. (New Zealand Board of 

 Science and Art, Manual No. 3.) Pp. x + 462. 

 (Wellington, N.Z. : Dominion Museum, 1922.) 

 225. 6d. ; paper, 185. 



(i) ^T^HE current theories of Alpine structure are 

 JL based on two main explanations. According 

 to one, Alpine mountains consist of bands of the crust 

 which have been crumpled by contraction consequent 

 on the diminishing size of the earth. According to the 

 second explanation — the Versluckung or the swallowing 

 theory of Schwinner — a band of the crust sinks into a 

 lower zone, and there undergoes intense compression, 

 accompanied by the metamorphism of its rocks. 



Dr. F. Heritsch, of Graz, discusses these two 

 hypotheses in a masterly survey of the principles of 

 Alpine geology. He deals mainly with the Eastern 

 Alps. The treatment is very technical and would be 

 easier to follow if illustrated by a general sketch map. 

 The first part of the book consists of a series of essays 

 on the principles of rock folding ; he therein discusses 

 the nature of geosj-nclines, of local and widespread 

 movements of the crust, and the formation of fore- 

 deeps. In his account of the widespread or epeiro- 

 genetic movements he lays stress on the oscillation 

 which often accompanies variations in coast levels. 

 He then discusses the phenomena of folding, ovcrfolding 



U I 



