5 2 4 SCIENCE PROGRESS 



The work opens with a tabular tree indicating the author's concept of matter 

 associated with energy from the standpoint of equilibrium, the main divisions 

 being into systems in equilibrium and systems not in equilibrium. The text is con- 

 veniently divided into three parts. Part I. deals with considerations based on the 

 kinetic theory, Part II. comprises considerations based on thermodynamics, whilst 

 the last part treats of considerations founded on thermodynamics and statistical 

 mechanics. Most of the newer work, such as Planck's quantum theory, Einstein's 

 extension of this, photo-reactions, low temperature, specific heats, etc., is to be 

 found in the final part, and not the least value of these volumes to English readers 

 lies in the fact that they contain the first simultaneous presentation in their own 

 language of these new theories and their mutual bearing on one another. 



The whole work is redolent of the spirit of inquiry, and at every point opposing 

 views are clearly stated and the evidence for each critically sifted. In this respect 

 the volume differs considerably from former text-books on physical chemistry, and 

 the feeling is aroused that the whole subject of physico-chemical science is being 

 passed in review by a mind determined to probe the truth. 



Text-books which are merely treasuries of facts and theories have at all times 

 a specific value, but when fact and theory are carefully weighed up together and 

 their bearing on one another evaluated we pass to the designation Classic. Most 

 readers will find it easy to place the present work in the latter category, 



C. S. G. 



GEOLOGY 



The Deposits of the Useful Minerals and Kocks. Their Origin, Form and 

 Content. Vol. II. By F. Beyschlag, J. H. L. Vogt, and P. Krusch. 

 Translated by S. J. TRUSCOTT, A.R.S.M. [Pp. xxi + 515-1262, with 176 

 illustrations.] (London : Macmillan & Co., Ltd., 191 6. Price 20s. net.) 



The second volume of this work more than fulfils the promise of the first. The 

 translator has done his work excellently, and British and American students of 

 ore-deposits will be grateful to him for his arduous labours on their behalf. He 

 has evidently taken into account the various criticisms offered in reviews of the 

 first volume, as is indeed acknowledged in the preface. The style, for example, is 

 much improved, at least for the present reviewer, by the freer translation of the 

 original German, with the result that there are very few of the stiff and stodgy 

 sentences so common in the first volume. We have very little criticism to offer 

 as to the manner of the second volume. " Nordengland" (p. 775), "federerz" 

 and " zundererz " (p. 779), and a few other German terms might have been given 

 their English equivalents. " Shale " would be a better term than " slate " in the 

 description of the Cleveland ironstone (p. 1023). " Trachyte-dolerite " (p. 564) is 

 a term strange to petrography ; and " Quartenary " (p. 1002) is an obvious 

 misprint. 



In his preface the translator proposes several new renderings of original 

 German terms. " Gangtonschiefer " is now translated as " lode-slate,'' instead of 

 "flucan," as in the first volume ; whilst the last-named term is taken to be the 

 equivalent of " Lettenkluft," and is thus used as the name of an occurrence rather 

 than a material. Similarly " Sahlband" is now translated as " lode-wall" instead 

 of " gouge." 



The geographical and subject indexes provided at the end of the second 

 volume cover the whole of the work, but the index published in Volume I. is not 

 incorporated in its entirety. Hence some references to subjects and places in the 



