460 



KNOWLEDGE. 



November, 1910. 



which the Palaeozoic. Mesozoic and Cainozoic rest, probably 

 represents a longer period of time than these three groups put 

 toijether. If it were intended to restrict the reference to the 

 fossiliferous rocks, then Pre-Cambrian or Archaean might 

 have been omitted from the stratigraphical table altogether. 

 Figure 56 is intended to give an idea of the appearance of a 

 granite, but actuallv it represents a granite-porphyry, a rock 

 of somewhat different aspect. The remainder of the book is 

 occupied with the technique of coal-mining. The methods of 

 proving, reaching and working the coal, the use of explosives, 

 the means of ventilating and lighting the shaft and workings, 

 the raising and preparation of coal for the market, are 

 expounded in simple language and with the aid of numerous 

 diagrams. Four chapters on elementary chemistry and physics 

 are intercalated in this part, which concludes with a chapter 

 on such miscellaneous subjects as electricity, surveying, 

 accidents, rescue appliances, ankylostomiasis, and baths. The 

 whole of this technical description, in which the author is on 

 his own ground, is excellently done. The style is clear and 

 direct, well suited to the type of boy for which the book is 

 intended. Further points for commendation are the freedom 

 from misprints, and an adequate index. No better book could 

 be taken up in the supplementary and continuation classes in 

 which pit-lads receive some training in the principles under- 

 lying their work, and we agree with the remark in the preface 

 that such instruction tends to reduce the deplorable number 

 of fatal and serious non-fatal accidents in the mines. 



The Bearing of Recent Theories on flie Xattire of the 



Earth's Interior upon the Question of Deep Mining. — Bv 



Professor E. H. L. Schwarz, A.R.C.Sc, F.G.S. Soiitli 



African Journal of Science. .April, 1910. pp. 234-241. 



(South .\frican Association for the Advancement of Science.) 



This paper is really a condensation of the author's daring 

 speculations on the nature of the interior of the earth which 

 were more extensively developed in his Causal Geology. He 

 is a whole-hearted supporter of Professor T. C. ChamberUn's 

 Planetismal Hypothesis. The earth's crust is believed to be 

 self-heating by means of various chemical reactions, radium, 

 and frictional heat, and is supposed to rest on a solid nucleus 

 which is probably near the temperature of outer space. On 

 this theory the temperature gradient in the crust will increase 

 downwards until a certain limit is reached, and beyond that 

 there will be a decrease. The author finds confirmation 

 for this idea in the low temperature gradients of South .Africa, 

 an ancient denuded region (the stalk end of Jean's pear- 

 shaped globe), which has not been covered by the sea 

 for an immense period, and therefore represents as deep a 

 part of the crust as can be got anywhere on the earth. 

 In view of the abov-e theory, the old objection to deep- 

 level mining on the score of temperature is disposed 

 of — in South Africa, at any rate. Whilst we do not endorse 

 many of the ideas contained in this paper, it is interesting to 

 find the problems of the earth's interior and origin so fully 

 and freshly discussed in South .\frica. 



PHYSICAL CHFNHSTKV. 



The Relation between Chemical Constitution and some 



Physical Properties. — By Samuel Smiles, D.Sc. 



pp. xiv. 4- 5S3. Crown 8vo. 7?-in. X 4i-in. 



(Longmans. 14 -.) 



This book forms one of a series edited by Sir William 

 Ramsay, of which ten \-olumes have already appeared, while 

 four more are announced as in preparation. The immense 

 development of the Physical side of Chemistr)- in recent years 

 is remarkable, and Dr. Smiles' book is itself a miiie of 

 information about the work done in certain directions, which 

 it would be difficult to obtain from the orignnal sources for any 

 chemist who did not know exactly where to look. As the 

 author points out in his preface, the relations between con- 

 stitution and optical rotation, electric conductivity and heat of 



combustion are dealt with in other volumes of the series. 

 Crystalline form has been omitted as requiring a \olume to 

 itself. But the student who wishes a statement of the present 

 state of knowledge on the relation of chemical constitution 

 to capillarity, viscosity, specific heat, volume, fusibility, boiling 

 point, refractive and dispersive power, absorption, fluorescence, 

 magnetic rotation, and electric absorption, will find in this 

 book abundant information, with many references to the 

 original sources. The author is careful to state that he has 

 written from the standpoint of the organic chemist. 



.4 Te.xt-hool; of Physical Chemistry Theory and 



Practice. — By Arthur W. Ewell, Ph.D. pp. ix. 4- 370. 



Si-in. X 5i-in. 



Ij. and A. Churchill. 9 6 net.) 



This book is written for .American students who have been 

 through the College course of elementary physics, chemistry, 

 and m,atheniatics. It will serve as a laboratory manual, and a 

 book of reference. The ground covered is very wide, and the 

 te.xt is intended to be supplemented by lectures ; but the 

 business-like brevity and conciseness of the statements and 

 explanations show the hand of an experienced teacher, and we 

 can imagine the book proving extremely useful to an English 

 student who wishes to revise old work, at the same time that 

 he is continuing his laboratory practice. The range of the 

 book may be gathered from the statements that it contains 

 sixty-three tables, that the subject matter ranges from the use 

 of the balance to radioactivity, and that sixty experiments and 

 twenty-nine collections of problems are included. 



Physical Chemistry : its bearing on Biology and Medicine. 



—By James C. Philip, M.A., Ph.D.. D.Sc. pp. vii. 4-312. 



7.J-in. X 45-in. 



(Edward .\rnold. 7 6 net.) 



This book is intended for students of biology and medicine 

 who wish to obtain a grasp of the fundamental principles 

 underlying the application of the methods and ideas of physical 

 chemistry to physiological and biological problems. It has 

 grown out of a course of lectures delivered to such students 

 in the University of London, and appears admirably adapted 

 for its purpose. Naturally stress is laid on such parts of the 

 subject as osmosis, permeability of membranes, colloidal 

 solutions, etc., which have a special bearing on the problems 

 in question, and the treatment is, as far as possible, non- 

 mathematical. The style is clear and easy. 



PHYSICS. 



Wonders of Physical Science. — By E. E. Fourxier. B.Sc. 

 7-in.X4n^-in. Pp. viii. 4- 201. 77 Illustrations. 



(Macniillan & Co. Price 1,6.) 



This is one of a projected Series of Readable Books in 

 Natural Knowledge. To quote from the publishers' note " An 

 intimate knowledge of the simplest fact in Nature can be 

 obtained only by personal observation or experiment . . . 

 but broad views of scientific thought and progress are secured 

 best from books in which the methods and results of investiga- 

 tion are stated in language which is simple without being 

 childish." In this little volume, which is intended to promote 

 interest in physical science, there are seventeen chapters, each 

 of which contains a bright and brief history of some 

 important discovery. The chapters on Archimedes, Dr. 

 Gilbert, the .\n Pump and the Electric Telegraph strike us as 

 particularly fresh, and indeed the whole book is admirably 

 suited to its purpose. In the chapter on Arabian Days we 

 find no reference to the Arabic numerals which have made 

 physical calculations possible ; and perhaps more might have 

 been made of Faraday's life and example in the chapter which 

 is headed by his name. The final chapter on Airships and 

 Flying Machines is somewhat unnecessary in a book of this 

 kind. 



