waste, feeding their flocks and herds alternately on the banks of the
Oxus and the Tejend, or finding a bare subsistence for them about the
ponds and pools left by the winter rains, represent, it is probable,
with sufficient faithfulness, the ancient inhabitants, who, whatever
their race, must always have been nomads, and can never have exceeded
a few hundred thousands. On this side Parthia must always have been
tolerably safe from attacks, unless the Cis-Oxianian tribes were
reinforced, as they sometimes were, by hordes from beyond the river.

On the north-east was Margiana, sometimes regarded as a country by
itself, sometimes reckoned a mere district of Bactria. This was the
tract of fertile land upon the Murg-ab, or ancient Margus river, which
is known among moderns as the district of Merv. The Murg-ab is a stream
flowing from the range of the Paropamisus, in a direction which is a
little east of north; it debouches from the mountains in about lat.
36° 25', and thence makes its way through the desert. Before it reaches
Merv, it is eighty yards wide and five feet deep, thus carrying a vast
body of water. By a judicious use of dykes and canals, this fertilizing
fluid was in ancient times carried to a distance of more than
twenty-five miles from the natural course of the river; and by these
means an oasis was created with a circumference of above 170, and
consequently a diameter of above fifty miles. This tract, inclosed on
every side by deserts, was among the most fertile of all known regions;
it was especially famous for its vines, which grew to such a size that
a single man could not encircle their stems with his two arms, and
bore clusters that were a yard long. Margiana possessed, however, as a
separate country, little military strength, and it was only as a
portion of some larger and more populous territory that it could become
formidable to the Parthians.