August io, 191 1] 



NATURE 



i73 



satisfy everyone. He gives us a marine Lower 

 Devonian series across south-west Ireland (Fig. 19), 

 the Glengarriff Grits being supposed to represent the 

 deposits of a land-locked bay. He carries the Upper 

 Senonian sea (Fig. 53 and p. 333) boldly into Scot- 

 land, Wales, and central Ireland, though flints are 

 scarce in the surface-deposits of some of the areas 

 thus invaded, and though they are not likely to have 

 been carried away by subsequent marine action (com- 

 pare p. 426). The rapidity of the oscillatory move- 

 ments in Cretaceous times is properly insisted on, if 

 we are to regard the chalk as a deep-water rather 

 than merely as a pure-water deposit. 



The consideration given by the author to the con- 

 ditions under which successive series were formed is 

 well seen in his comparison of the Bunter pebble-beds 

 with the alluvium of the Helmand River (p. 234), or 

 in his very interesting discussion of the Pliocene and 

 Pleistocene deposits (pp. 404-61). The references to 

 recent literature show how keenly he has watched the 

 progress of research. We thus have Mr. Hickling's 

 views on the Permian affinities of the outliers of sand- 

 stone near Dumfries, which are often supposed to be 

 of Triassic age (p. 208); Prof. Watts 's suggestion 

 (p. 379) of the Eocene age of igneous rocks in the 

 English Midlands ; and Mr. Bernard Smith (p. 237) 

 on the " skerries " of the Keuper marls. Anyone who 

 has become attracted by the varied surface of our 

 islands, or even by the scenery of a single county, 

 will find his views enlarged when he follows Mr. 

 Jukes-Browne into the past. He will at once feel the 

 complexity of the subject, and the vast range of the 

 events that have determined the present forms of hill 

 and dale. After reading a few pages, a healthy re- 

 action sets in against the superficial physical descrip- 

 tions in which we all are liable to indulge. No one 

 can read "The Building of the British Isles" without 

 becoming again a student. The author's expressions 

 of personal opinion will stimulate inquiry rather than 

 remove all doubt. This is the manner of the true 

 scientific teacher, and we feel that Mr. Jukes-Browne 

 has made new claims on our regard. 



To enjoy a book so full of detail, one must see and 

 remember the country it describes. In ten years, in 

 holidays of a few days at a time, the geologist may 

 learn a great deal of the aspect of our islands. To 

 anyone who has happily crossed the open country, from 

 the rocky coves of Cornwall to the heather-covered 

 slopes above the Moray Firth, or from the sunlit dunes 

 of Donegal to the grey mud-flats near the Nore, these 

 pages will make a singular appeal. Perhaps we mav 

 read into the book a good deal obtained from other 

 sources, since it presupposes a general knowledge of 

 the great tectonic movements that have affected the 

 European area. In spite of what we have said, it is 

 intended primarily for the geologist. 



Every British or Irish geologist, moreover, will find 

 points that he will like to criticise. Why, for in- 

 stance, should stratified gravels be difficult to under- 

 stand (p. 440) on the hypothesis that they result from 

 the washing of boulder-clay? Does not the melting 

 ice supply the very agent for their stratification? A 

 "very deep basin" would not be required, (p- 128) for 

 the accumulation of the Cornstone series in Wales, 

 NO. 2l8o, VOL. 87] 



but only a continuously subsiding floor. The omission 

 of the Snowdon area from the description of the 

 Ordovician rocks of North Wales seems surprising 

 (pp. 68 and 69), and no stranger would suspect the 

 immense part played by volcanic action in originating 

 the scenery between the Conwy and Llanberis. Other 

 geologists, however, must now enjoy the book, and 

 discover their particular grievances to the author, who 

 has done so much to help them. G. A. J. C. 



TECHNICAL THERMODYNAMICS. 

 Applied Thermodynamics for Engineers. By Prof, 

 W. D. Ennis. Pp. viii4-438. (London : Constable 

 and Co., Ltd., 1910.) Price 24s. net. 



THIS is by far the most comprehensive book pub- 

 lished in the English language on the subject 

 of technical thermodynamics. It contains an account, 

 brief but lucid, of the transformations of heat and 

 mechanical energy which occur in almost every con- 

 ceivable industrial process. As evidence of this wide- 

 spread treatment, it is only necessary to mention that 

 among the processes discussed are the development of 

 power in the internal combustion engine, in the steam 

 engine, in the hot-air engine, air and gas compressors, 

 distillation plant, mechanical refrigeration, fusion and 

 liquefaction of gases. To the discussion of these 

 various topics Prof. Ennis brings experience gained 

 in the mechanical engineering side of the Polytechnic 

 Institute of Brooklyn, and it is clear that in his 

 study of these problems he has made a digest of 

 recent work on the subject of gases and vapours. His 

 style of writing is graphic, forceful — but eccentric in 

 so far as he seems actually to seek opportunities for 

 splitting the infinitive; in fact, he does so no fewer 

 than four times in the first five pages of the book, 

 and after that we gave up counting. 



A useful feature is the appendage to each chapter of 

 a brief synopsis of its contents, together with a 

 bibliography of the authorities quoted. Problems are 

 added for the use of students, but the author does not 

 commit himself to their solution, a cautious step in a 

 first edition. 



Prof. Ennis's immediate aim is expressed in the 

 following words : — 



"Thermodynamics is physics, not mathematics or 

 logic. This book takes a middle ground between 

 those text-books which replace all theory by em- 

 piricism and that of the other class of treatises which 

 are too apt to ignore the engineering significance of 

 their vocabulary of differential equations. We here 

 aim to present' ideal operations, to show how they 

 are modified in practice, to amplify underlying prin- 

 ciples, and to stop when the further application of 

 those principles becomes a matter of machine design." 



The author may fairly be said to have carried out these 

 intentions successfully, in spite of the necessarily con- 

 siderable labour which must have gone to the compila- 

 tion of so compressed a treatise. 



It is not possible to discuss at length the methods 

 followed by the author even in a section of the 

 subjects he deals with, but some call for passing 

 notice. Thus, he introduces early the idea of in- 

 creasing specific heats of gases, and uses a formula 



