blossom--we can well understand how it came to be said of old, that
"Egypt was the gift of the river." Not that the lively Greek, who first
used the expression, divined exactly the scientific truth of the matter.
The fancy of Herodotus saw Africa, originally, _doubly_ severed from
Asia by two parallel _fjords_, one running inland northwards from the
Indian Ocean, as the Red Sea does to this day, and the other penetrating
inland southwards from the Mediterranean to an equal or greater
distance! The Nile, he said, pouring itself into this latter _fjord_,
had by degrees filled it up, and had then gone on and by further
deposits turned into land a large piece of the "sea of the Greeks," as
was evident from the projection of the shore of the Delta beyond the
general coast-line of Africa eastward and westward; and, he added, "I am
convinced, for my own part, that if the Nile should please to divert his
waters from their present bed into the Red Sea, he would fill it up and
turn it into dry land in the space of twenty thousand years, or maybe in
half that time--for he is a mighty river and a most energetic one."
Here, in this last expression, he is thoroughly right, though the method
of the Nile's energy has been other than he supposed. The Nile, working
from its immense reservoirs in the equatorial regions, has gradually
scooped itself out a deep bed in the sand and rock of the desert, which
must have originally extended across the whole of northern Africa from
the Atlantic to the Red Sea. Having scooped itself out this bed to a
depth, in places, of three hundred feet from the desert level, it has
then proceeded partially to fill it up with its own deposits. Occupying,
when it is at its height, the entire bed, and presenting at that time
the appearance of a vast lake, or succession of lakes, it deposes every
day a portion of sediment over the whole space which it covers: then,
contracting gradually, it leaves at the base of the hills, on both
sides, or at any rate on one, a strip of land fresh dressed with mud,
which gets wider daily as the waters still recede, until yards grow into