igh interest historically,
since it is the scene of the dawn of European intelligence; the western
is bounded by the Italian peninsula, Sicily, and the African promontory
of Cape Bon on one side, and at the other has as its portal the Straits
of Gibraltar. The temperature is ten or twelve degrees higher than the
Atlantic, and, since much of the water is removed by evaporation, it is
necessarily more saline than that ocean. Its colour is green where
shallow, blue where deep.

[Sidenote: Secular geological movement of Europe and Asia, and its
social consequences.]

For countless centuries Asia has experienced a slow upward movement, not
only affecting her own topography, but likewise that of her European
dependency. There was a time when the great sandy desert of Gobi was
the bed of a sea which communicated through the Caspian with the Baltic,
as may be proved not only by existing geographical facts, but also from
geological considerations. It is only necessary, for this purpose, to
inspect the imperfect maps that have been published of the Silurian and
even tertiary periods. The vertical displacement of Europe, during and
since the latter period, has indisputably been more than 2000 feet in
many places. The effects of such movements on the flora and fauna of a
region must, in the course of time, be very important, for an elevation
of 350 feet is equal to one degree of cold in the mean annual
temperature, or to sixty miles on the surface northward. Nor has this
slow disturbance ended. Again and again, in historic times, have its
results operated fearfully on Europe, by forcibly precipitating the
Asiatic nomades along the great path-zone; again and again, through such
changes of level, have they been rendered waterless, and thus driven
into a forced emigration. Some of their rivers, as the Oxus and
Jaxartes, have, within the records of history, been dry for several
years. To these topographical changes, rather than to political
influences, we must impute many of the most celebrated tribal invasions.
It has been the custom to refer these events to an excessive
overpopulation periodically occurring in Central Asia, or to the
ambition of warlike chieftains. Doubtless those regions are well adapted
to human life, and hence liable to overpopulation, considering the
pursuits man there follows, and doubtless there have been occasions on
which those nations have been put in motion by their princes; but the
modern historian canno