IX.] HIS GEOGRAPHICAL TREATISE. 183
projection either of India or of Africa. The country, in respect of
which his information is most strikingly in advance of that possessed
by previous writers, is Arabia. This is accounted for by the exist-
ence on either side of that land of the two great monarchies of
Egypt and Syria, the latter of which had its seat at Babylon or
Seleucia; for, by means of the commerce which these promoted,
a number of trade-routes were developed in various parts of the
interior of the intervening territory. So unique was the oppor-
tunity thus afforded for obtaining intelligence about a land which
has at all times been difficult to penetrate, that even Strabo,
though writing in the Augustan age, was largely dependent on
Eratosthenes for his account of Arabia.