134 



GEOGRAPHY 



[Sect. ¥• 



f 



S. 



the iiiountain 



recesses to their final disemhogulng in the 

 sea, their course, their currentSj and their shores afford 

 an endless variety of remarks and ohservations. The 

 depth and colour of the water, the rate at which it flows 

 the eddies and currents hy which its course is marked, 

 are all deserving of notice, as are also the rocks and 

 shoals which obstruct its uniform progress, either inter- 

 fering with its navigation, or, by projecting beyond its 

 ordinary banks, throwing back the rushing torrent on the 

 opposite shores, as has been so eloquently described by 

 the Latin poet : 



Vidimus flavum Tiberim, retor 

 Littore Etrusco yiolenter undisj 

 Ire dejectum monumenta regis, 



Tempiaque Vestse 



thus causing the gradual fall of the cliffs by undermining 

 their precarious foundation. Nor in describing the size 

 or extent of rivers should we neglect to state how far up 

 they are navigable, to what vessels, and by what means, 

 whether the mouth is constantly free, or whether closed 

 by a bar, and how mvich water there generally is over it. 

 Some rivers, however, are not only closed by a bar, but, 

 as in the case of Western Australia, are, during periods 

 when the water is low, completely masked by the sand- 



hills or dunes which are blown up, forming a continuous 



bank with the hills which skirt the shores, and onlv when 

 freshets of more than ordinary force come down are these 

 sandy barriers overthrown^ and the rivers enabled io 

 find an uninterrupted outlet. In other cases the effect 

 of beaches thrown up bt the constant set of currents in 

 one direction is not so absolutely insurmountable, the 

 streams are only partially deflected from their prop 



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