482 



NATURE 



[March 23, 1905 



11 iis divisions and subdivisions. In chapter iv. the 

 luthor deals in the same manner with South African 

 i;eology, with the literature of which he appears to be 

 well acquainted. Respecting this literature, he re- 

 marks (p. 39) :— 



" So ist denn die Geschichte der geologischen 

 Forschung in Siidafrika eine wahre Komodic der 

 Irrungon. So viel Forscher, so viel Ansichten ! Ja, 

 in und derselbe Forscher . . . haben ihre AufTassung 

 '. ii'dcrholt gewechselt. ..." 



He debates anew the many doubtful points in the 

 correlation of the rocks, and expresses his views 

 ihereon. This chapter with its bibliographical 

 appendix might be used as a general introduction to 

 ihe study of South .African geology. It is illustrated 

 t)y a geological map of .\frica south of io° S. lat. 

 (Blatt ii. in the " Kartenband "), which, though rough 

 in execution and crude in colouring, serves to give at 

 a glance the main lines on which the rocks of this part 

 of the continent are arranged. The climate of South 

 -Africa and of the Kalahari afford material for 

 chapter v., which includes a summary of the author's 

 personal observations on the weather, and concludes 

 with some very acceptable notes on the rapidly pro- 

 gressive desiccation of the country, based on a com- 

 parison of the experiences of the earlier and later 

 ixplorers. 



Then follows a solid block of chapters — vi. to xxiv., 

 pp. 105-530 — devoted, except for an interlude in 

 chapters xvi. and xvii., to the detailed account of the 

 author's investigations in the several districts visited — 

 the Kwebe and neighbouring hill ranges ; the region 

 bordering on Ngami and the Botletle River; the Haina 

 N'eldt ; the Chanse Veldt and the adjacent German 

 frontier ; the western part of the Okavango basin with 

 its rapidly perishing river-system, of which the de- 

 scription is of extreme interest ; the Kaukau Veldt ; 

 the Rung Veldt ; and the Mahura Veldt. With many 

 an " L'berblick " and " Riickblick," " Ubersicht " and 

 " Folgerung," the author pursues his way through 

 masses of detailed observations, all carefully classified, 

 ■-ubdivided, and marked with sign-posts in the form 

 of head-lines; and many a pertinent' interrogative 

 >entence, spaced out in the text, is conscientiously 

 answered or as conscientiously evaded by further 

 questions. It is in these chapters that the operation of 

 the .Auxiliaries is most forcefully felt. To the general 

 reader the greater part of these details must be arid, as 

 befits the description of a desert, yet not without 

 refreshing oases here and there. Nor can it be denied 

 that in a region undergoing such rapid changes in 

 respect to rainfall and drainage-systems, the full par- 

 ticulars as to the exact condition of all the water-pans 

 at the time that they were examined are certain to 

 prove of value in the future for purposes of compari- 

 son ; while to the geological traveller who may here- 

 after visit the Middle Kalahari the whole of these 

 chapters are likely to prove of service. Indeed, when 

 we remember how much more might have been written 

 from the impressions of a trained observer at work in 

 a new country during two whole years, we feel, on 

 the whole, inclined to be grateful to Dr. Passarge for 

 hi^ moderation. 



NO. "847, VOL. 71] 



The two chapters already menttoned as forming an 

 interlude to the topographical details are comparatively 

 amusing. The first (xvi.) describes the geological 

 effect of the burrowing animals of the desert, both 

 mammals and insects, upon the superficial formations, 

 with numerical calculations as to its efficacy in pro- 

 ducing large results. The second gives a summarised 

 description of the structure of the deposits found on 

 the sites of the desiccated lakelets or " Kalkpfannen " 

 of a certain district, with a particular inquiry into the 

 origin of the water-holes (" Pfannenkrater ") that in 

 many cases still persist within them, .\ftor stating 

 the problem in his favourite manner, under various 

 headings in interrogative form, the author proceeds 

 to show that all the peculiar features of the water- 

 holes may be assigned to the agency of the wild 

 animals that have used them as drinking places and 

 bath-tubs. He enumerates these animals ; shows from 

 the records of the first white travellers how multi- 

 tudinous they once were ; gathers data from the Berlin 

 Zoological Gardens as to the drinking capacity of most 

 of the larger herbivores ; supplements this with observ- 

 ations on the drinking of his draught animals when 

 trekking in the desert ; calculates the amount of dis- 

 solved and suspended matter in the water of the 

 " pans," and how much would be carried away in 

 the interiors of the beasts that drank it; and also how 

 much they removed on their exteriors after their 

 occasional mud-baths. Then, the cubic space of the 

 water-hole being known, and the number of its former 

 visitants estimated, a simple calculation brings out 

 the number of years in which, by this agency, the 

 hole could have been produced. 



Is there not the germ of a glorious question for 

 some future examination paper in the following 

 sentences? — 



" Nehmen wir die Oberfiache eines Nashorns auf 

 6 qm an und die Kruste nach jedem Schlammbad auf 

 I mm, so triigt jedes Tier 6 1 Schlamm fort. Wenn 

 also 10 dicser Tiere wiihrend der Trockenzeit (i8o 

 Tage) tiiglich baden, tragcn sie im Jahr lo-S cbm 

 Schlamm fort, im Laufe von weniger als 2000 Jahren 

 also den Inhalt einer Pfanne von 20,000 cbm. Das 

 wiirden 10 Nashorner alkin fertig bringcn ! " (p. 321). 



Let us acknowledge, however, that from this 

 singfular line of research a very important deduction 

 is drawn, and is in keeping with all the other 

 evidence : — 



" Denn diese Zahl besagt, dass vor dieser Zeit — 

 sagen wir rund 6000-7000 Jahren — das Chansefeld ein 

 wesentlich anderes Kliina gehabt haDen muss " 

 (p- 3-22)- 



After giving, in chapter xxx., a summary of our 

 scanty knowledge of the vast area of the Kalahari 

 beyond the regions which he visited, the author pro- 

 ceeds to epitomise his own observations and to deal 

 with the broader aspects of his subject. The oro- 

 graphic and hydrographic conditions of the Kalahari 

 as a whole are briefly stated in chapter xxxi., with a 

 summary of the evidence for the rapidly progressive 

 desiccation of the land in a definite direction. Then 

 follow chapters on the basement-rocks (das Grund- 

 gestein) of the region ; on the development and 



