<;K<M;RAIMIY 



UROLOGY 



147 



y and it* European and native explores be 



leu. In Atiica niucli light has been thro \\n 



ic character and condition of the African 



ifiit In many of its greatest explorers as 



, Park, Clapuertxm, tlio Landers, Burton, 



Speke. Itartli, Vogel, Livingstone, Cameron, Stan 



|t-\ . Thomson, Schweinfurtn, Nacbtigal, Junker, 



mill Kmin Pasha; General Gordon and his sub- 



ordinate ollieers ; the French in Senegambia and on 



tin- t pi-el- Niger; \Vissinium and Pogge, and other 



otliccrs of the Congo I'Yee State; German explorers 



in c;i>t :iinl central Africa, and the missionaries 



riotis denominations. In Australia, although 



much -till remains to lie done, t lie obscurity which 



him-,' over the interior has Keen to a great extent 



diminished by tin- explorations of Start, Eyre, 



I.eiclihardt, and the brothers Gregory; and still 



mure by the bighly important labours of Burke 



Wills, \\-ho in 1860 crossed the Australian 



continent from Melbourne to Carpentaria. The 



>lishment in 1872 of a telegraph line from 



Adelaide to Port Darwin right across the continent, 



and the maintenance of stations along the line, 



formed an admirable base for further exploration. 



Giles, NYarhurton, and Forrest forced their way in 



nearly parallel lines to the west coast. The labours 



of these and other explorers indicate that much of 



the continent of Australia, though often covered 



with dense growth of spinifex, acacia, and eucalyp- 



tu>. i< not available for colonisation by Europeans. 



The government surveys of the various European 

 countries, of the British possessions, and of other 

 mil i.-ed states have not only added to a detailed 

 knowledge of the face of the earth, but given us 

 more precise ideas of its shape. Again, various 

 deep-sea exploring expeditions of recent years, the 

 chief among which was that sent out by the English 

 government in the Challenger (q.v. ), have added 

 greatly to our knowledge of the geography of the 



Mas. 



The progress of recent discovery has been aided 



the encouragement given to exploration by the 

 governments or different countries, and by the 

 (Moris of the numerous geographical societies, of 

 which there are now over one hundred ; while the 

 constantly increasing mass of information collected 

 by scientific explorers is rapidly diffusing correct 

 information in regard to distant regions. 



On the subject of geographical discovery, the following 

 works may be consulted with advantage : Bunbury's 

 History of Ancient Geography (1880) ; Vivien de Sainte- 

 Martin's Histoire de Utoyraphie ; Kiepert's Manual of 

 Ancient Orography ( 1881 ) ; J'rfcis de Geographic Unii-er- 

 ttte, by Malte Brun ; Humboldt's Hist. crit. de I' Hist, de 

 irupkie, and the Cosmoi ; Hitter's Asien ; Kloeden's 

 tfdkunde ; lieclus, NbuveUe Geographic Universelle ; 

 .Stanford's Compendium of Geography and Travel, based 

 llwald ; H. F. Tozer, A History of Ancient Geography 

 : 0. R. Beazley, Th? Ituim f M<l.< rn (i'<i*tr<iphy 

 '.I" i. And si-u Petermann's Mitt< ilinmi n, the Proc. 

 i. <i,i*i. Sue., and the d'riiiirHfiliixcltui Jahrbueh. 



Geology ( Gr. ge, the earth ; ' logos, ' a dis- 

 course') is the science of the earth that science, 

 namely, which has for its object the study of the 

 various constituents of the earth's crust, with a 

 vie\\- to discover how those materials have been 

 -,'ati-d and caused to assume the appearances 

 which they now present. Geology, in short, is an 

 inquiry into the history and development of the 

 earth's crust, and of the several floras and faunas 

 which have successively clothed and peopled its 

 surface. As a science geology is comparatively 

 young, although it can hardly be doubted that 

 from a very early period the phenomena with 

 which it deals must nave claimed some attention. 

 It is easy, indeed, to trace in old mythologies and 

 legends the influence of the geological features 

 nf the land upon the human imagination. Volcanic 



eruptions, earthquakes, avalanche*, and 

 the havoc- of torrential water*, and the destructive 

 action of waves and breakers have unquestionably 

 left their imj>russ upon the -n|-i -t it imi- and beliefs 

 of all primitive peonies. One may believe that 

 many of the remarkable scientific premonition- 

 which are met with in oriental cosmogonies and 

 the early writings of the Greeks may have been 

 suggested by geological phenomena. The occur- 

 rence of sea-shells in the rocks of mountain* and 

 regions far removed from the sea may well have 

 given rise to the oriental belief in the alternate 

 destruction and renovation of the world. Pytha- 

 goras and Strabo both recognised that changes had 

 taken place on the surface of the earth, but neither 

 appears to have got beyond the observation of a 

 few obvious phenomena their explanations of 

 which are hardly entitled to be considered more 

 than vague guesses. It is not until we reach the 

 close of the 15th century that we find geological 

 phenomena attracting the attention of competent 

 observers. With the investigations of the cele- 

 brated painter, Leonardo da Vinci, together with 

 those of Fracastoro, a new departure was taken. 

 The numerous fossil shells discovered in engineer- 

 ing operations were appealed to by them as evidence 

 of former geographical changes their method of 

 reasoning being consistent and logical. Unfortu- 

 nately it did not convince either their contem- 

 poraries or immediate successors some of whom 

 held the extraordinary view that shells and other 

 fossil organic remains were not really what they 

 appeared to be, but the result of a plastic force 

 which had somehow fashioned them in the Ixwels 

 of the earth. Fossils were further supposed to be 

 the results of the fermentation of fatty matter, or 

 of terrestrial exhalations, or of the influence of the 

 heavenly bodies, or, finally, to be simply earthy 

 concretions or sports of nature. Others, however, 

 while maintaining that fossils were in truth the 

 relics of formerly living creatures, held the opinion 

 that all these had been buried at the time of the 

 Noacbian deluge. This controversy lasted for more 

 than a hundred years, but long after the true 

 character of fossils had become generally admitted 

 their entombment in the strata continued to be 

 attributed to the action of the deluge. This belief 

 prevailed through the 17th and 18th centuries, and 

 sadly interfered with the growth of geology ; the 

 prolonged infancy of which must be largely attrib- 

 uted to its influence. Steno, a Dane, who lived 

 in Italy in the middle of the 17th century, would 

 appear to have been the first to observe a succession 

 in the strata. Hitherto stratified rocks had not 

 been differentiated ; they were all lumped together 

 as representing the tumultuous deposits of the 

 Noachian deluge. Steno, however, distinguished 

 between marine and fresh-water formations, and 

 showed that there were rocks older than the fossili- 

 ferous strata in which no organic remains occurred. 

 Nevertheless, this clear-sighted observer could not 

 free himself from the fashionable hypotheses of his 

 day. While a belief in the universality of the 

 Noachian deluge was prevalent, many strange 

 ' theories of the earth,' such as that by Bishop 

 Burnet, saw the light. These showed not only 

 how the world had been evolved out of chaos, how 

 it fared before, during, and after the deluge, but in 

 what precise manner it was eventually to be wound 

 up ami consumed. The ' theories' referred to differed 

 in detail, but their imaginative authors agreed in 

 the notion of an interior abyss, whence at the time 

 of the Noachian catastrophe the waters rushed, 

 breaking up and bursting through the crust of the 

 earth to cover its surface, and whither, after the 

 deluge, they returned again. 



Leibnitz (1680) proposed the bold theory that 

 the earth was originally in a molten state, and that 



