December i6, 1922] 



NA TURE 



801 



based on crumpling masses that have a considerable 

 lateral as well as vertical movement. Meanwhile, 

 Wegener, flinging down his gage, certainly calls on us 

 to justify such faiths as we at present hold. His 

 principal geographic rearrangements are shown in a 

 series of small maps, in one of which the northern 

 lands are rearranged so as to explain the latest glacial 

 epoch. The Permo-Carboniferous glaciation presents 

 difficulties, as was pointed out in a notice of the 

 excellent papers by Du Toit (Nature, vol. 109, p. 

 757) ; but Wegener, when he has clustered his land- 

 masses around the pole, shifts the pole from point to 

 point among them, to suit their special idiosyncrasies. 

 Nothing daunts so bold a champion. The hand of 

 the master presses on the sial blocks or on the polar 

 axis, and all goes well with the hypothesis. 



Has the author considered, however, that no re- 

 groupings of the furniture of the earth will account for 

 the simultaneous reduction of ice-masses in all glaciated 

 regions at the present day ? Can, moreover, the 

 evidence for general rises of temperature in the past 

 be so lightly set aside ? Can — but these questions are 

 endless ; those who still hope for simple explanations 

 may well turn their eyes for light and inspiration, 

 with Akhenaten, to the sun. 



Grenville A. J. Cole. 



A New Treatise on Chemistry. 



A Comprehensive Treatise cm Inorganic and Theoretical 

 Chemistry. By Dr. J. W. Mellor. Vol. i. Pp. 

 xvi + 1065. Vol. 2. Pp. viii + 894. (London : 

 Longmans, Green and Co., 1922.) 3/. 35. net each 

 vol. 



THE writing of a " Comprehensive Treatise on 

 Inorganic Chemistry " presents a problem 

 which becomes more and more difficult with each 

 successive year. The small text-books of a century 

 ago soon required to be expanded into a series of 

 volumes such as were issued by Watts in 1868, and in 

 the English translation of Gmelin, of which 19 volumes 

 were issued between 1848 and 1872. In recent years 

 the growth of the subject has been so rapid that nearly 

 all the more recent successes have been scored by 

 teams of workers, such as those who have collaborated 

 in the production of Thorpe's " Dictionary of Applied 

 Chemistry " in England, and of Moissan's " Traite de 

 chimie minerale " in France, as well as in the more 

 recent German productions. Even so, as Dr. Mellor 

 reminds us in his preface, the seventh edition of Gmelin, 

 begun in 1905, is not yet completed, while three other 

 unfinished compilations date back to 1905, 1900, and 

 1874 respectively. For every reason it is greatly to 

 be hoped that Dr. Mellor will be able to carry through 

 NO. 2772, VOL. I ioj 



to completion the series of volumes of which the first 

 two have now been issued. 



In reviewing these two volumes (and perhaps paying 

 more attention to the first than to the second), it is 

 necessary in the first place to offer respectful homage 

 to the author for the vast range of accurate information 

 which he has gathered together. Almost every item 

 of fact appears to have been abstracted from the 

 original sources, and by a system which has left very 

 little room for casual errors. It is, moreover, remark- 

 able to find that an author, whose interests have 

 generally been thought to centre themselves in the 

 mathematical and physical aspects of chemistry, 

 should lie in a position also to deal in such an able 

 manner with other topics, such as the early history of 

 the science, which occupies a substantial portion of 

 the first volume. In these chapters his references are 

 often more numerous and earlier than those which are 

 given in the more formal histories ; thus, included in 

 volume 1 are a number of unexpected references to the 

 history of combustion before Jean Rev. of oxygen 

 before Priestley, and of crystallography before Haiiy, 

 while volume 2 contains, on page 419, an amazing quota- 

 tion from Roger Bacon, from which it might perhaps 

 be supposed that metallic sodium had already been 

 prepared in the thirteenth century ! If the historical 

 portion of the volume is dull reading, the major portion 

 of the blame must be ascribed to the infertile character 

 of the science during two of the three periods into 

 which its history is divided by the author, namely, the 

 first or mythological period, and the second or philo- 

 sophical period, before it finally reached in the seven- 

 teenth century the third or scientific era. Certainly 

 the 50 pages which are devoted to these preliminary 

 stages fully justify the policy which has been adopted 

 generally by teachers, even of historical chemistry, of 

 curtailing within the narrowest limits the study of 

 everything prior to about 1600 a.d. A lingering doubt 

 as to whether this early period is quite so dull as it 

 appears has, however, been raised in the mind of the 

 reviewer by the sudden arousal of his interest when, 

 on page 107, a series of quotations are given from a 

 translation of Lucretius instead of a mere second- 

 hand summary of his views on atoms. 



The materials for the Treatise have already been 

 used in part in the author's " Modern Inorganic 

 Chemistry"; conversely, the treatise bears evidence 

 that it has been based, in part at least, upon an 

 expansion of the text-book. This hypothesis at any 

 v es to account for some features in the arrange- 

 ment of the treatise which are awkward and perhaps 

 undesirable. Thus, in a text-book, which the student 

 is expected to read consecutively from cover to cover, 

 and in which the assumption is made that the reader 



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