olute abruptness. In Egypt, then, more than anywhere else,
one sees with one's own eyes that mud and moisture are the very
conditions of mundane fertility.

Beyond Cairo, as one descends seaward, the mud begins to open out
fan-wise and form a delta. The narrow mountain ranges no longer hem it
in. It has room to expand and spread itself freely over the surrounding
country, won by degrees from the Mediterranean. At the mouths the mud
pours out into the sea and forms fresh deposits constantly on the
bottom, which are gradually silting up still newer lands to seaward.
Slow as is the progress of this land-forming action, there can be no
doubt that the Nile has the intention of filling up by degrees the
whole eastern Mediterranean, and that in process of time--say in no
more than a few million years or so, a mere bagatelle to the
geologist--with the aid of the Po and some other lesser streams, it
will transform the entire basin of the inland sea into a level and
cultivable plain, like Bengal or Mesopotamia, themselves (as we shall
see) the final result of just such silting action.

It is so very important, for those who wish to see things "as clear as
mud," to understand this prime principle of the formation of mud-lands,
that I shall make no apology for insisting on it further in some little
detail; for when one comes to look the matter plainly in the face, one
can see in a minute that almost all the big things in human history
have been entirely dependent upon the mud of the great rivers. Thebes
and Memphis, Rameses and Amenhotep, based their civilisation absolutely
upon the mud of Nile. The bricks of Babylon were moulded of Euphrates
mud; the greatness of Nineveh reposed on the silt of the Tigris. Upper
India is the Indus; Agra and Delhi are Ganges and Jumna mud; China is
the Hoang Ho and the Yang-tse-Kiang; Burmah is the paddy field of the
Irrawaddy delta. And so many great plains in either hemisphere consist
really of nothing else but mud-banks of almost incredible extent,
filling up prehistoric Baltics and Mediterraneans, that a glance at the
probable course of future evolution in this respect may help us to
understand and to realize more fully the gigantic scale of some past
accumulations.

As a preliminary canter I shall trot out first the valley of the Po,
the existing mud flat best known by personal experience to the feet and
eyes of the tweed-clad English tourist. Everybody who has looked down
upon the wide Lomb