66 



and again deposit continually in places where 

 they diminish in velocity. 



If these reflexions throw some light on the 

 interesting phenomenon of cataracts, they are 

 not sufficient, I confess, to explain the exagge- 

 rated accounts, which the ancients* have left 

 us of the rapids of Syene. Did they not attri- 

 bute to this lower fall what they had vaguely 

 learned of the upper falls of the river, those of 

 Nubia and Dongola, which are more numerous, 

 and more formidable ^ ? Syene stood on the 



* Strabo must be excepted, whose description is no less 

 simple than accurate. According to this author, the rapidity 

 and direction of the currents have changed since the century 

 before our era ; the chellal could then be ascended on both 

 sides. There now exists a navigable channel only on one 

 side. The passage of the cataract is therefore become less 

 easy. Strab. Lib. xvii, p. 817 (translation of Mr. Letronne, 

 vol. v, p. 428). 



t See Jemard, in the Description de V Egypt e ancienne, 

 Syene, p. 17 and 28. Messrs. Burkhardt and Banks, Lord 

 Belmore, and Mr. Salt, have recently visited these upper 

 cataracts. Those of Sukkoy, situate above Ebsambal, at the 

 boundary between the zones of sandstone and granite, are 

 heard at a distance of two miles. South of the great Djena- 

 del, in the desert of Batn el Hadjar, several less considerable 

 rapids follow. The southernmost cataract of the Nile, or 

 rather of the two Niles united, is that of Koke, near Napata. 

 (See the learned article Egypt, by Doctor Thomas Young, in 

 the 4th vol. of the Encyclop. Britannica.) Had the ancients 

 a confused notion of the great cataracts of the eastern Nile, or 

 the Blue Nile, which have an elevation of more than 200 feet 



