1840.] Sketch of the Physical Geography of Seistan. 711 



be met with, except a few rounded pebbles in the beds of rivers. The 



soil is either the light and soluble earth of the desert, or the still lighter 



alluvial deposit, and there is hardly one tree, and not one of any size, 



in the whole country. From the north and north-east, it receives the 



waters of numerous rivers, which partaking of the nature of mountain 



torrents, at one time of the year rush down with great violence, almost 



black with mud, and at others are either quite dry, or flow in a clear, 



languid and shallow stream. 



It requires but little knowledge of Physical Geography, to judge of 



the effect of a large body of water discharged in this 

 Effect of the rivers. .,, . ■,.... , . . ,, 



manner, with varying velocity, into a basm, incapable, 



from its nature, of offering the slightest resistance to its progress. The 



water hurries away to the lowest spots, and there, when its turbulence 



has subsided, drops its loads of earth, till in process of time these low 



spots have become elevated, and the water is driven to some other place. 



It necessarily results, that the level of the country must constantly be 



altering, and that as the whole bed of the lake is thus gradually filling 



up, the waters spread themselves over a large surface every year. This 



extension is much assisted by the deposits which take place in the beds 



of the rivers at their mouths, which deposits are of course ever on the 



increase as the current becomes less rapid, when layer after layer of 



settling earth diminishes the slope. In consequence of this filling up of 



their beds, nearly all these rivers overflow their banks on entering Seistan. 



Of the correctness of these views, the whole country exhibits many proofs, 



even to the passing traveller ; and a scientific resident 

 Ancient appearance . , , i 1 1 i , , , , , , « , . 



of the country. might probably be able to develop much of the in- 

 teresting history of the progressive changes. For a 

 long period of years, however, Seistan would seem to have presented much 

 the same general appearance as is attempted to be delineated in the annexed 

 sketch. 



The violent action of the swollen streams was in a great measure 

 moderated by large bodies of water being drawn off in canals, which 

 were conducted, in some places, as far as forty miles, through dry and 

 sandy tracts. Massive embankments had been also constructed by rich 

 and enlightened governments, which prevented the water from flowing 

 without controul, and confined it within certain bounds for the purposes 

 of cultivation. 



It is only of late years that a very remarkable change has taken place 

 in the aspect of the country, to explain which it will be necessary to say 

 a few words on the geography of its lakes and rivers, at the period repre- 

 sented in the sketch, when Captain Christie visited Seistan. 



