Page:Travels to Discover the Source of the Nile - In the Years 1768, 1769, 1770, 1771, 1772, and 1773 volume 3.djvu/697

 THE SOURCE OF THE NILE                      673

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 soil, than to leave it behind in a state to accumulate.

The land of Egypt slopes gently from the midle of the valley to the foot of the mountains on each side, so that the center is really the highest part of the valley, and in the middle of this runs the Nile *. At right angles with the stream large trenches are cut to the foot of the mountains, in which canals the water enters, and insensibly flows down to the end of these trences, where it diffuses itself over the level ground.

As the river swells, these canals fill with water, which goes seeking a level to the foot of the montains; so that now the flood, which begins to gestagnate towards the bank of the river, acquires no motion, as the calithes are formed at right angles to the stream. Sometimes, indeed, the river is so high, when the rains in Ethiopia are excessive, that the back-water joins the current of the Nile, when immediately it communicates its motion to the stagnant water, and sweeps away every thing that is planted into the sea. It is a mistake then to assert,-the fuller the Nile, the better for Egypt.

It has been said by various authors, that it was necessary Egypt should be measured every year, on account of

Vol. III. 4Q                     the


 * see this figure in Dr. Sl., Chap.II.   3.p.385