Tigris. Two of the six have been already described in these volumes, and
therefore will not need to detain us here; but a few words must be
said with respect to each of the remaining four, if our sketch of the
geography of the Empire is to make any approach to completeness.

The Nile was only in the latter part of its course a Persian stream.
Flowing, as we now know that it does, from within a short distance of
the equator, it had accomplished more than three fourths of its course
before it entered a Persian province. It ran, however, through Persian
territory a distance of about six hundred miles, and conferred on
the tract through which it passed immeasurable benefits. The Greeks
sometimes maintained that "Egypt was the gift of the river;" and, though
this was very far from being a correct statement in the sense intended,
there is a meaning of the words in which we may accept them as
expressing a fact. Egypt is only what she is through her river. The Nile
gives her all that makes her valuable. This broad, ample, and unfailing
stream not only by its annual inundation enriches the soil and prepares
it for tillage in a manner that renders only the lightest further labor
necessary, but serves as a reservoir from which inexhaustible supplies
of the precious fluid can be obtained throughout the whole of the year.
The water, which rises towards the end of June, begins to subside early
in October, and for half the year--from December till June--Egypt is
only cultivable through irrigation. She produces, however, during this
period, excellent crops--even at the present day, when there are few
canals--from the facility with which water is obtained, by means of
a very simple engine, out of the channel of the Nile. This unfailing
supply enabled the cultivator to obtain a second, a third, and even
sometimes a fourth crop from the same land within the space of a year.

The course of the Nile from Elephantine, where it entered Egypt, to