June i i, 190S] 



NA TURE 



12' 



some future time, if not now. The statement that 

 Edison is now devoting hhiiself exclusively to pure 

 science thus becomes welcome news. 



The book is illustrated in the approved style with 

 " Edison at the age of four," " Edison at nineteen," 

 " Edison at forty," and so forth, also " Mr. and Mrs. 

 Edison in the laboratory"; altogether more than a 

 score of illustrations. 



\\'e think that one person is kept rather more in 

 the background than is really necessary in this book, 

 that person being Mr. Francis Arthur Jones. He 

 shows such an intimate knowledge of and friend- 

 ship with Mr. and Mrs. Edison that some further 

 reference to his personal relations with them would 

 not only be justifiable, but would give an added in- 

 terest to the biography. 



We must, however, direct attention to the statement 

 on the last? page : — 



" Of the force hidden in coal about 15 per cent, 

 only is available, the other 85 per cent, being wasted 

 That is why it requires so many hundreds of tons o. 

 coal to propel a liner across the .-Xtlantic. \\'hen the 

 problem of generating electricitv direct is solved, then 

 two or three tons of coal only will be needed for the 

 same purpose." 



" Many hundreds of tons " is, of course, a some- 

 what elastic term, and we do not know whether Mr. 

 Edison or Mr. Francis Arthur Jones is responsible 

 for the above statement, but taking, say, five hundred 

 tons by way of argument, it is surely a little unneces- 

 sary for either of those gentlemen to imperil his re- 

 putation for the sake of seventy-two tons of coal. 



G. H. Bryan. 



A FRENCH TREATISE OX GEOLOGY. 



Traite de Geologic. I. Lcs Plieiioinencs geologiqites. 

 By E. Haug. Pp. 536; 195 figs., 71 plates. (Paris : 

 Armand Colin, 1907.) Price 12.50 francs. 



AMONG the most important of the perpetual needs 

 of geology is the frequent renewal of the inter- 

 national supply of advanced te.\t-books, from which 

 the general conclusions of foreign authorities and 

 the outlines of the geology of foreign lands may be 

 learnt apart from the now overwhelming mass of 

 original literature. In such books the interests of the 

 local students, to whom illustrations of normal phe- 

 nomena are most important, to some extent conflict 

 with the requirements of foreign geologists, who will 

 profit by the description of exceptional occurrences; 

 but fortunately most authors of advanced works may 

 be trusted to enliven their books by a sufficient num- 

 ber of special cases to make them useful to foreign 

 geologists. The issue of an extensive treatise on 

 geology by Prof. Emile Haug, of the University of 

 Paris, is, therefore, to be warmly welcomed by British 

 geplogists, as we may expect it to give an instructive 

 account of geological phenomena in France, a guide 

 to the original literature, and a clear exposition of 

 the current state of geological thought in that 

 country. 



Prof. Hang's first volume deals with geological pro- 

 cesses and materials. In his statement of the rela- 



NO. 2015, VOL. 78] 



tions of geology to allied sciences he lays stress on 

 the essential importance in geology of the succession 

 of phenomena ; and this idea finds frequent expres- 

 sion in the book, from the first chapter on the geo- 

 logical cycle to the last on theories of orogenesis 

 The volume opens with an account of the general 

 morphology of the earth, and he says that " the 

 geological history of our planet is nothing else than 

 the history of its successive cycles"; and he regards 

 the three main subdivisions of geological history, for 

 which he uses the names Primary, .Secondary and 

 Tertiary, as each a great cycle beginning with very 

 active sedimentation, followed by intense crustal 

 movements, and closing with a period of great conse- 

 quent denudation. He suggests that the " prc- 

 primary " was a similar cycle, and that the " post- 

 tertiary " will be another." 



In his description of rocks he follows the guidance 

 ^ the same principle by describing them under the 

 headings of lithogenesis, orogenesis, and glypto- 

 genesis, i.e. their formation, modification, and de- 

 struction. He then proceeds to biological geology, 

 discussing the life of the continents and the distribu- 

 tion of botanical and zoological provinces. The 

 author attaches no value to the theory of the per- 

 manence of oceans and basins; and although he 

 notices the objections of Koken and Freeh to the 

 assumed Pacific continent, he warmly maintains its 

 foimer existence. According to Prof. Haug, there 

 were five great continents in Secondary times — the 

 North-Atlantic continent, the South Atlantic or 

 Brazilio-African continent, the Sino-Siberian con- 

 tinent, the Austral-Indian-Madagascan continent, and 

 the Pacific continent. He maintains the Mesozoic ex- 

 istence of these continents, and the fundamental dift'er- 

 ence from the present distribution of land and water, 

 as a necessary consequence, both of the tectonic struc- 

 ture of the earth and of the distribution of animals 

 and plants. He maintains that : — 



" The enigmas of zoological geography are abso- 

 lutelv insoluble if one regards only the existing state 

 of things. But as soon as one admits that the dis- 

 tribution of lands and seas was not, in geological 

 epochs anter;or to our own, the same as it is to-day, 

 all these facts become clear in a new light." 



After three chapters dealing with the sedimentary 

 rocks, and one on mineral-fuels, the author discusses 

 tectonic geology, crustal movements, and the pheno- 

 mena of volcanoes and earthquakes. The chapter 

 on fuels shows the author's thorough chemical know- 

 ledge of his subject. The excellent chapters on 

 mountain structure are illustrated by numerous clear 

 diagrams to explain the views and terms of Suess, 

 and" bv artistic photographs of those French Aloine 

 regions where the author has made important re- 

 searches. 



In the treatment of so wide a range of subjects 

 there are naturally a few slips; thus the author four 

 times refers to Ceratodus as living in Tasmania in- 

 stead of Queensland, and he follows another important 

 recent text-book in the statement that the New Zea- 

 land geysers were destroyed by the eruption of 1884. 

 That eruption, however, though it destroyed the sinter 



