forces its way through the barrier, and so contrives to reach the sea.
This is the case, especially, on the south, where the coast chain is
pierced by a number of streams, some of which have their sources at a
considerable distance inland. On the north the Heri-rud, or River of
Herat, makes its escape in a similar way from the plateau, but only to
be absorbed, after passing through two mountain chains, in the sands of
the Kharesm. Thus by far the greater portion of this region is desert
throughout the year, while, as the summer advances, large tracts, which
in the spring were green, are burnt up--the rivers shrink back towards
their sources--the whole plateau becomes dry and parched--and the
traveller wonders that any portion of it should be inhabited.

It must not be supposed that the entire plateau of which we have been
speaking is to the eye a single level and unbroken plain. In the western
portion of the region the plains are constantly intersected by "brown,
irregular, rocky ridges," rising to no great height, but serving to
condense the vapors held in the air, and furnishing thereby springs
and wells of inestimable value to the inhabitants. In the southern and
eastern districts "immense" ranges of mountains are said to occur; and
the south-eastern as well as the north-eastern corners of the plateau
are little else than confused masses of giant elevations. Vast flats,
however, are found. In the Great Salt Desert, which extends from Kashan
and Koum to the Deriah or "Sea" in which the Helmend terminates, and
in the sandy desert of Seistan, which lies east and south-east of that
lake, reaching from near Furrah to the Mekran mountains, plains of above
a hundred miles in extent appear to occur, sometimes formed of loose
sand, which the wind raises into waves like those of the sea, sometimes
hard and gravelly, or of baked and indurated clay.

The tract in question, which at the present day is divided between