1852.] On the Sites of Nikaia and Boukephalon. 229 



accumulates its forces : but the instant a runnel has surmounted the 

 pass, the whole is again in motion, urging all its might upon the point ; 

 cleaving, melting, rending, overthrowing, until once again the tremend- 

 ous chaos of water, forest, mud, and the bodies of men and beasts, is 

 hurled forward with portentous impetus, through the narrow gorge 

 upon the deep soil of the yet scarcely furrowed valley. So long as 

 the course of this torrent lies between mountains, the walls of living 

 rock prevent its spread and hold it to the depth perhaps of three or 

 four hundred feet. But as it issues forth upon the nearly level valley 

 with astonishing velocity it spreads out on either side, widening as it 

 goes, licking up the clay and finer particles of sand, to hurry them 

 with its waters to the ocean. Thus is abraded all the superficial soil 

 to the depth perhaps of two hundred feet, and thus is formed the 

 river basin, properly so called, to the breadth at Koharr of three or four 

 miles. But now the reservoir of waters is somewhat exhausted. 

 The supply is reduced to the daily tribute paid to the Hydaspes by 

 the mountain spring. The course of the river between the mountains 

 is that of a deep and rapid mountain stream but as it emerges into 

 the basin recently delved for it in the open valley where the differences 

 of level are not very abrupt ; the velocity of its waters causes their 

 deflection into many separate currents, as grape-shot spreads on losing 

 the constraint of the gun: or as a stream of water poured from a 

 height is split into rain ere it reach the earth, by the opposition of 

 the atmospheric medium. And thus are formed many islands ; some 

 at once, before the channel has been worn very deep, others subse- 

 quently, when the surface of the channel has been still further abraded. 

 The former are on a level with the river banks on either side : have 

 deep firm clay soil and a stratification corresponding with that of the 

 banks ; they bear crops, have often villages, and are easily mistaken 

 for the further bank of the river. The latter are much lower than 

 the river banks, and emerge only because the channels have sunk 

 around them. They have been wholly despoiled of their clay soil 

 and only shingle and sand remain to them : the latter sometimes 

 original, sometimes the deposit of inundations. These islands often 

 bear the tamarisk : but as they are more or less subject to inundation, 

 permanent houses are not erected there. As the river proceeds, it 

 receives the tribute of the plains ; it finds a basin growing more and 



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