July 27, 1911] 



NATURE 



107 



the variation of the position of absorption bands 

 which is likely to be produced by association of sol- 

 vent with solute. Due recognition is given to the 

 importance of the work now being carried out by 

 Purvis on the selective absorption of substances in 

 the state of vapour, in which case the influence of 

 solvent is quite eliminated. 



Considerable interest attaches to the attempted 

 physical explanation of selective absorption, and use 

 is made of the mass of experimental material accumu- 

 lated by Hartley, Baly, and others. Baly's idea of 

 " isorropesis " does not commend itself to the author, 

 who is in favour of an electronic theory. 



As may be expected in a book written in the 

 Leipzig laboratory, much attention is given to the 

 quinonoid rearrangement frequently assumed when a 

 change in colour accompanies salt formation. One 

 might gather from this portion of the work that 

 "chinoide Umlagerung " was specially associated with 

 Leipzig; e.g. on p. 169 one finds regarding phenol- 

 phthalein : — 



" Der Beweis, dass den Salzen chinoide Konstitution 

 zukommt, beruht auf der Existenz zweier ver- 

 schiedener Ather. Neben dem farblosen laktoiden 

 Dimethylather existiert ein roter chinoider Ather, der 

 zuerst von Green und King dargestellt und eingehend 

 auch von K. H. Meyer und Hantzsch, untersucht 

 wurde." 



One would scarcely realise the great importance of 

 Prof. Green's work on the phthaleins bv reading this 

 passage ; and it may be pointed out (see pp. 176-7) 

 that the hydroxy- and amino-azo-compounds have 

 engaged the attention of several workers. 



The colours of complex salts introduces some in- 

 organic chemistry, whilst in the last few pages — 

 devoted to method — spectroscopes, spectrographs, &c, 

 are described, and an outline of the manner of work- 

 ing with these instruments is given. J. T. H. 



THE NON-METALLIC MINERALS OF 



ECONOMIC VALUE. 



Die wichtigsten Lagerstatten der Nicht-Erze. By Dr. 



O. Stutzer. Erster Teil, Graphit, Diamant, 



Schwefel, Phosphnt. Pp. xv + 474. (Berlin: 



Gebruder Borntraeger, 191 1.) Price 16 marks. 



T1IIS work is designed to supplement the treatise 

 of Prof. Beck on " Mineral Veins and their 

 Contents," by giving an account of the deposits of 

 those useful mineral substances which are not classed 

 as "ores." The first volume, now* published, is 

 evidently the fruit of a vast amount of labour and 

 bibliographical research, and deals only with four 

 classes of materials, to each of which the amount of 

 mace devoted is as follows — graphite, 88 pages; 

 diamonds, 94 pages; sulphur, Si pages; and phos- 

 phates, 198 pages. In the case of each of these 

 materials, the author, after preliminary notices of its 

 mineralogical characters and modes of occurrence, pro- 

 ceeds to compile from the most varied sources descrip- 

 tions of each of the districts in which it occurs. These 

 descriptions are illustrated by page blocks (of which 

 there are no fewer than 10S in the volume) giving 

 NO. 2178, VOL. 87] 



sketch maps, sections, drawings, and photographs. 

 Very miscellaneous information is supplied in these 

 accounts of localities, including statistics of annual 

 yield with prices and total values, and even, in some 

 cases, examples of forms of agreement between sellers 

 and buyers. In the case of the South African diamond 

 fields, however, these statistics are, unfortunately, not 

 brought down to later date than the year 1908. 



As a rule, the references to authorities are ample 

 and satisfactory, but we notice some marked excep- 

 tions. The author's acquaintance with British scien- 

 tific literature would appear to be much more limited 

 than his knowledge of German, American, and even 

 Japanese sources of information. Thus a section of 

 the Upware phosphatic beds is stated to be "after 

 W. Keeping-Penrose," and the puzzled English reader 

 is left to find out that the information about British 

 deposits is obtained, at second hand, from a Bulletin 

 of the United States Geological Survey, written by 

 Mr. R. A. F. Penrose, jun., in 1888! We are re- 

 minded of the ingenuous remark of a compatriot of 

 the author, who, when it was pointed out to him 

 that a research he had published had been long before 

 anticipated in this country, said, "Ah, that was buried 

 in the catacombs of the Royal Society's Trans- 

 actions! " In like manner, we find that Mr. Teall's 

 interesting account of the phosphatised trachyte of 

 Clipperton Atoll, published in the Quarterly Journal 

 of the Geological Society in 189S, is ignored, while 

 many less interesting deposits in the Pacific are fully 

 described. 



After the discussions of the distribution and statis- 

 tics of the materials in the various districts, the author 

 proceeds to consider such general questions as 

 their origin, artificial formation, and metamorphoses. 

 The treatment of these more purely scientific problems, 

 however, is quite subordinate to that of economic 

 and statistical questions, and little of novelty or special 

 interest is to be found in these sections of the book. 



An exception to this may, perhaps, be found in the 

 useful abstract, on pp. 254 to 262, of the views that 

 have been put forward concerning the origin of beds 

 of sulphur, including the possible production of some 

 of these deposits through the agency of bacteria, like 

 Beggiatoa and Chromatium. On the whole, however, 

 the work is to be commended for its technological 

 rather than its scientific value. 



ELECTRICITY AND MAGNETISM. 



(1) Beispiele und Uebungen aits Elektrizitdt und Mag- 

 netismus. By Prof. R. Weber. Fiinfte Auflage. 

 Pp. viii + 330. (Leipzig and Berlin : B. G. Teubner, 

 1910.) Price 4.S0 marks. 



(2) Experimentelle Elektrizitatslehre, vcrbunden mil 

 einer Einfiihrung in die Maxwellsche und die Elek- 

 tronentheorie der Elektrizitat und des Lichts. By 

 Prof. H. Starke. Zweite Auflage. Pp. xvi + 662. 

 (Leipzig and Berlin : B. G. Teubner, 1910.) Price 

 12 marks. 



(1) "T^HIS is a collection of nearly nine hundred 



J- examples in electricity and magnetism. They 



are all numerical in character, and each is completely 



