CATARACTS AND INUNDATIONS. 17 



cubits, when the canal of Cairo \vas cut : after this it continued 

 rising six weeks longer ; but then it only rose from three to five 

 inches a day ; for, spreading over the land, and entering the canals, 

 though more water may descend than before, yet its rise is less 

 considerable ; as after the opening of that canal, the others are un- 

 closed at fixed times, and those that water the lower grounds the 

 last. These canals are carried along the highest parts of the coun. 

 trv, that the water mav hence be conveyed to the vallies. 



** ' * 



The Nile has one character of great peculiarity. Other rivers 

 being supplied by rivulets, the ground is lowest near the banks : but 

 as no water flows into the Nile in its passage through Egypt, and 

 as it is necessary that this river should overflow the land, the country 

 is generally lower at a distance from the Nile than near it; and in 

 most parts of the land seems to have a gradual descent from the 

 Nile to the foot of the hills, which may be said to begin at those 

 sandy parts already mentioned, as being a mile or two distant from 

 them, which, rising toward the mountains ina gentle ascent, are 

 never overflowed. 



The cataracts of the Nile will be described in a subsequent 

 section. 



The SENEGAL is the next most remarkable river in Africa ; called 

 by Ptolemy The Daradus. D'Anriile, who follows that ancient 

 geographer, supposes it to take its rise among the mountains af Ca- 

 phas, lying about 1 4 north latitude, and nearly on the meridian 

 of Greenwich. It takes a western 'course, tending somewhat 

 to the northward, through sixteen degrees of longitude, and, in- 

 cluding its bendings, must extend more than eleven hundred miles. 

 It has this very distinguishing peculiarity, that when arrived within 

 fifteen miles of the sea, it winds suddenly round to the south, and 

 proceeds in that direction through more than seventy miles, when it 

 discharges its waters into the sea, forming at its mouth the little 

 island of St. Louis, in latitude i6" 10' north. This river is said 

 jo be navigable for near three hundred leagues up the country ; 

 but the dangers to which Europeans are exposed by the ferocity of 

 the natives who inhabit its banks, deter from ail endeavours to ex- 

 plore it, sucli attempts having proved fatal to most of those who 

 have ever embarked in it. 



Some geographers have supposed the Senegal to be a continuation 

 VOL. in. c 



