runs among the hills, it receives from both sides numerous and important
tributaries; but from the meridian of Balkh those fail entirely, and
for above 800 miles the Oxus pursues its solitary way, unaugmented by a
single affluent, across the waste of Tartary, rolling through the desert
a wealth of waters, which must diminish, but which does not seem very
sensibly to diminish, by evaporation. At Kilef, sixty miles north-west
of Balkh, the width of the river is 350 yards; at Khodja Salih, thirty
miles lower down, it is 823 yards with a depth of twenty feet; at Kerki,
seventy miles below Khodja Salih, it is "twice the width of the Danube
at Buda-Pesth," or about 940 yards; at Betik, on the route between
Bokhara and Merv, its width has diminished to 650 yards, but its depth
has increased to twenty-nine feet. Finally, at Gorlen Hezaresp near
Khiva, the breadth of the Oxus is so great that both banks are hardly
distinguishable at the same time; but the stream is here comparatively
shallow, ceasing to be navigable at about this point. The present course
of the Oxus from its rise in Lake Sir-i-Kol to its termination in the
Sea of Aral is estimated at 1400 miles. Anciently its course must have
been still longer. The Oxus, in the time of the Achaemenian kings, fell
into the Caspian by a channel which can even now be traced. Its length
was thus increased by at least 450 miles, and, exceeding that of the
Jaxartes, fell but little short of the length of the Indus.

The Oxus, like the Nile and the Indus, has a periodical swell, which
lasts from May to October. It does not, however, overflow its
hanks. Under a scientific system of irrigation it is probable that a
considerable belt of land on either side of its course might be brought
under cultivation. But at present the extreme limit to which culture
is carried, except in the immediate vicinity of Khiva, seems to be four
miles; while often, in the absence of human care, the desert creeps up
to the very brink of the river.