REVIEWS 667 



reason to suppose that the climate of the Mediterranean has not been affected 

 in a similar manner since the time of Homer, let us say. All the lectures 

 are coloured with broad washes rather than by means of undue stippling of 

 detail. Young people would like to have seen more drawings of extinct 

 animals. The book is certainly an achievement on behalf of scientific 

 education. 



Coal in Great Britain. The Composition, Structure and Resources of the 

 Coal-fields, Visible and Concealed, of Great Britain. By Walcot 

 Gibson, D.Sc, F.G.S. [Pp. viii+311, with 8 plates and 50 illus- 

 trations.] (London : Edward Arnold, 1920. Price 21s. net.) 



One wonders who will really benefit by reading this book. In the Preface 

 the author says that it " is intended to supply mining engineers, mine-owners, 

 and mining students with a concise account of the more important facts 

 relating to the geology of coal generally, and to the composition, structure, 

 and resources of the coal-fields of Great Britain in particular." But a book 

 containing innumerable facts, many of doubtful validity, which does not give 

 a single reference to the sources of these facts cannot be truly useful to 

 students. It is, on the contrary, a type of book injurious to the mentality 

 of students, for it leaves them either with the idea that the author is the 

 authoritative source of all the statements, or with vague and baseless con- 

 cepts in no way connected with their real source. While it is neither 

 necessary nor would it be advisable to quote full references for most facts 

 mentioned, yet, in order to give students a soUd ground-work, it is essential 

 that the authority should be given for the most important facts. The 

 references must, moreover, be more than mere names, and sufficiently complete 

 bibliographic quotations for an intelligent student to lay his hands on the 

 originals in a good library. To refer every now and then to papers in the 

 Transactions of the Royal Society, in the Quarterly Journal of the Geological 

 Society, and the memoirs of our own and foreign Geological Surveys, and 

 the great academies, and so on, is indeed a most valuable part of the student's 

 training. It is true that the average mining student will never himself 

 conduct a research ; but, unless he is introduced to research methods, or is, 

 at least, made aware of the type of work on which all his knowledge is based, 

 he wall never have a thorough grasp of his subject, nor will he be able to take 

 advantage of any exceptional opportunity which may arise by which he 

 may himself assist in the accumulation of scientific knowledge. 



This book, moreover, is far from being an immaculate guide ; indeed, it 

 is full of obscurities and inaccuracies, particularly in the earlier chapters. 

 The later chapters dealing with the distribution of the actual coal-basins 

 in England, the series of the seams, etc., depending more on the personal 

 experience of Mr. Walcot Gibson (who is well known to be an experienced 

 geologist), are much more reliable than the earlier chapters dealing with the 

 generalities and scientific aspects of the subject, in which there is an immense 

 amount to criticise. At the very beginning of the book, for instance, the 

 author reveals the fact that he has not kept abreast of recent knowledge 

 even regarding the actual appearance and outward form of coal. One 

 could find half a dozen faults by the second page of the book. On the third 

 page the significance of the presence of alumina in the ash of coals is mini- 

 mised by the author's example — that a species of Lycopodium " contains 

 as much as 6-7 per cent, of ash " — made without stating that, of the ash 

 in some Lycopodiums, more than 40 per cent, consists of alumina salts, 

 while the greater part of aU other families in the vegetable kingdom contain 

 no alumina at all in their ash, and the rest, with the exception of the Lyco- 

 podiacese, only a small percentage, generally less than two. 



Then, again, the book suffers from lack of precision : e.g., in the chapter 

 deahng with " Coal as a Rock," while the volume is an account of the " Coal 



