April 24, 19 13] 



NATURE 



ASPECTS OF THE EARTH. 



((1) Lehrbuch der Grundivasser- und Quellenkunde. 

 Fur Geologen, Hydrologen, Bohrunternehmer, 

 Brunnenbauer, Bergleute, Bauingenieure und 

 Hygieniker. By Prof. K. Keilhack. Pp. xi + 

 545. (Berlin: Gebriider Borntraeger, 1912.) 

 Price 20 marks. 

 {2) The Geology oj Soils and Substrata. With 

 Special Reference to Agriculture, Estates, and 

 Sanitation. By H. B. Woodward. Pp. xvi + 

 366. (London : E. Arnold, 1912.) Price 

 7-s_ 6d. net. 

 (3) Die erklarende Beschreibung der Landformen. 

 By Prof. W. M. Davis. Deutsch bearbeitet von 

 Dr. A. Riihl. Pp. xviii+565. (Leipzig and 

 Berlin: B. G. Teubner, 1912.) Price 11 marks. 

 <i) T)ROF. KEILHACK has produced a book 

 J7 on water-supply which presents a re- 

 markable contrast with the brief treatment of the 

 subject in many works on engineering. Yet he 

 regards these five hundred tall and handsome 

 pages as constituting a preliminary "Lehrbuch," 

 leading up to a future " Handbuch " of Teutonic 

 magnitude. The geologist here subordinates him- 

 self willingly to his technical purpose. The kinds 

 of rocks are dealt with in a few short sentences, 

 but their structure and the passage-ways for 

 water in them are at once impressed upon the 

 reader as of paramount importance. The char- 

 acters of soils as water-bearers receive rather 

 slight attention, and the necessity for dis- 

 criminating between the " fine earth " used ex- 

 perimentally and the soil as part of the earth's 

 crust, with all the stones in it, seems left to the 

 intelligence of the reader. 



In all questions involving maps Prof. Keilhack 

 is on ground that is specially his own, and he 

 makes good use of the beautiful products of the 

 Prussian Geological Survey. The discussion of 

 the form of the surface of the subterranean water- 

 table is unusually detailed. The problems of the 

 European karstlands are considered ; but the 

 author probably leaves for his still larger treatise 

 the interesting feature of water-supply in more 

 arid countries, such as rivers disappearing into 

 sandy wastes, the origins of oases, and the salts 

 deposited in the surface-zone of excessive evapora- 

 tion. Prof. Keilhack 's book is an excellent 

 example of the application of scientific research, 

 wide and without ulterior motive, to the stimu- 

 lating needs of human enterprise. 



(2) Mr. H. B. Woodward's latest addition to 

 Arnold's Geological Series is an attempt to 

 look at soils from a geological point of view, and 

 at the strata below them from the attitude of an 

 agriculturist. The proper treatment of the soil is 

 NO. 226Q. VOL. Ol"i 



rapidly becoming a matter for the organic chemist 

 and the biologist, but the foundation on which the 

 soil-activities are based is an aggregate of mineral 

 particles spaced in very various ways. The soil- 

 forming minerals are rather briefly treated on 

 pp. 55-6, and the calcium fluoride and chloride 

 of apatite have somehow got attached to dolo- 

 mite. The beneficial character of some of these 

 minerals and the deadly effect of others are not 

 indicated at this stage ; but we find a good deal 

 of diffused information when we reach the accounts 

 of soils formed on various types of rock. The 

 vexed question of what is "clay" is left alone, 

 but we may hesitate to accept the statement 

 (p. 78) that the Kimeridge, Gault, and London 

 Clays contain "up to 95 per cent, clay." The 

 remark on p. 73 that "alumina, in the form of 

 silicate of aluminia or clay," absorbs and retains 

 moisture and serves as a binding material does 

 little to help us towards understanding the rock 

 known as clay. Analyses of the clays mentioned 

 above, moreover, are given on p. 59, and show 

 at the most 50 per cent, of aluminium silicate. 



If we feel that the first part of the book does 

 not quite realise the author's aim, and does not 

 explain the soils and their structures to an agri- 

 culturist as a geologist might explain a landscape 

 to a painter, the latter section will convey much 

 special information to landowners in the British 

 Isles. The soils on the subdivisions of our 

 stratified series are described by one who knows 

 their aspect well, and these chapters form a 

 general account of the superficial deposits of 

 England, with many useful notes on those of Scot- 

 land and of Ireland. 



(3) Prof. W. M. Davis has always a question 

 to ask which must be answered in the field itself. 

 At times he may seem to ignore the mineral details 

 which lie at the root of rock-structure, and there- 

 fore at the root of the features produced during a 

 cycle of erosion. But he rightly, on p. vii. of the 

 present work, distinguishes between geological 

 and geographical description ; in the latter, all 

 attention must be concentrated on the surface- 

 forms as they are to-day. The lectures delivered 

 in German by Prof. Davis in 1908-9 at the 

 University of Berlin are here presented, with the 

 assistance of Dr. Riihl, as a general treatise on 

 land-forms. They are illustrated by the author's 

 line-drawings, minute and thoughtful, like the 

 work of Albrecht Di'irer, and sometimes present- 

 ing, as the earth does, too many problems in the 

 limits of a single scene. 



Anyone who examines these drawings will be 

 made to understand features that he remembers 

 viewing casually, perhaps even from a railway 

 train ; and now for the first time he perceives 



