ii SCIENCE PROGRESS. 



cold which set in soon after the close of the Pliocene, and to have completely died out only a 

 few thousands of years ago ; but, in the present edition, at least four or five interglacial 

 periods are thought necessary to explain the phenomena described. 



A very valuable feature in the present edition is the sketch of the ice age in America 

 which has been drawn up by Professor T. C. Chamberlin, who stands in much the same 

 relation to glacial geology in the United States as Dr. James Geikie does in this country. 

 The Great Ice Age has been largely rewritten, is well brought up to date, and is illustrated by 

 a number of excellent maps and sketches. 



Papers and Notes on the Glacial Geology of Great Britain and Ireland. By the late Henry 

 Carvill Lewis, M.A., F.G.S. Edited from his unpublished MSS., with an introduction 

 by Henry W. Crosskey, LL. D. , F.G.S. London: Longmans & Co., 1894. 



The late Professor H. C. Lewis was a man of rare scientific attainments, of remarkable 

 industry, and of high promise, who devoted himself enthusiastically to the study of glacial 

 phenomena on both sides of the Atlantic. Had his life been spared, there can be little doubt 

 that his great powers and opportunities for research would have resulted in much new light 

 being thrown on the very difficult problems which occupied his attention. In the book before 

 us his widow has gathered together, with loving care, all that remains of the work of an able 

 geologist and gifted writer. In his case, doubtless, further observations would have led to 

 modifications of some of the views, and to corrections of some of the statements, contained in 

 the present volume. 



The introduction to the book, by the late Dr. Crosskey, whose loss geologists have now 

 also to deplore, is a very able and judicious piece of work, and serves to make clear to the 

 reader what were the ideas and suggestions upon the subject of glacial phenomena for which 

 we are indebted to Carvill Lewis. 



It may serve to illustrate the difficulty of explaining and of correlating with one another 

 the very local and variable deposits known as " drifts," if we compare the general conclusions 

 of the work we are now considering with those of the Great Ice Age. The latter work regards 

 the boulder clay of England as having been accumulated under a vast ice-sheet ; the former 

 maintains that it was deposited in a set of extra morainic lakes. Dr. James Geikie, as we have 

 seen, argues in favour of a complicated series of glacial and interglacial periods, while Pro- 

 fessor Carvill Lewis insisted that there was no break whatever in the continuity of the glacial 

 period. 



The A rt of Projection. By an Expert. London: E. A. Beckett, 1893. 



The above work is a " Complete Magic Lantern Manual," and includes a " synopsis of 

 the perfect manipulation of a triple lantern and effects". 



It is evidently written by one who is practically acquainted with the subject, but the 

 writer's style is so extraordinary that a feeling of irritation is constantly present whilst reading 

 his descriptions. A single example will illustrate this: "The next operation after choosing 

 the object we wish to show upon the screen, and here it is advised that unless some definite 

 subject is taken for class demonstration, to manage all the slides in a series, so as to admit of 

 the same power objective being used, it will save much time to the operator in changing both 

 the object glass and substage condenser". The spelling also is very shaky, "loose" for 

 " lose," " non compus mentus," etc. The book contains valuable hints, and it is a pity that 

 it is spoiled by such defects. 



A Text-Book of Statics. By William Briggs, M.A., LL.B., F.R.A.S., and G. B. Bryan, M.A. 



London : W. B. Clive. 

 This is one of the volumes in the " University Tutorial Series," and, like the rest of the 

 books in the same series, affords a ready means of getting up the subject for an examination 

 in a short time. For this purpose the work will doubtless prove of use. 



Cloudland. By Rev. W. Clement Ley, M.A., F.R.Met.Soc. London: Edward Stanford, 



1894. 

 This is a " Study on the Structure and Characters of Clouds," with special reference to 

 their effects on the weather. It is well written, excellently illustrated with reproductions of 

 water-colour drawings and photographs, and in every way deserves to be carefully studied by 

 those who wish to be able to foretell the weather by observing the appearance of the sky. It 

 is obviously the work of one who has devoted much time and thought to the subject. 



