THE SOURCE OF THE NILE. 673 
J 
the Nile, being a. torrent falling from very high ground in 
Ethiopia, were this valley concave, the violent rapidity, or 
motion, would be much likelier to carry away mud and foil, 
than to leave it behind in a ftate to accumulate. 
Tue land of Egypt flopes gently from the middle of the 
valley to the foot of the mountains on each fide, fo that 
the center is really the higheft part of the valley, and in 
the middle of this runs the Nile*. At right angles with 
the ftream large trenches are cut to the foot of the moun- 
tains, in which canals the water enters, and infenfibly flows 
down to the end of thefe trenches, where it diffufes itfelf 
over the level ground. 
As the river fwells, thefe canals fill with water, which 
goes feeking a level to the foot of the mountains ; fo that 
now the flood; which begins to reftagnate towards the bank 
of the river, acquires no motion, as the califhes are formed 
at right angles to the ftream. Sometimes, indeed, the ri- 
ver is fo high, when the rains in Ethiopia are exceifive, that 
the back-water joins the current of the Nile, when imme- 
diately it communicates its motion to the ftagnant water, 
and {weeps away every thing that is planted into the fea, 
It is a miftake then to affert,—the fuller the Nile, the bet- 
ter for Egypt. 
Ir has been faid by various authors, that it was necef- 
fary Egypt fhould be meafured every year, on account of 
Vou. Il. 4Q. the 
® See this figure in Dr Shaw, chap, ii, fe€t. 3. p- 385. 
