Though in direct distance, as the crow flies, Babylon is not more than 450 miles from Damascus, or more than 520 from Jerusalem, yet the necessary detour by Aleppo is so great that it lengthens the distance, in the one case by 250, in the other by 380 miles.

From so remote a centre it was impossible for the life-blood to circulate very vigorously to the extremities.
The Empire was on the whole fertile and well-watered.

The two great streams of Western Asia--the Tigris and the Euphrates--which afforded an abundant supply of the invaluable fluid to the most important of the provinces, those of the south-east, have already been described at length; as have also the chief streams of the Mesopotamian district, the Belik and the Khabour.

But as yet in this work no account has been given of a number of important rivers in the extreme east and the extreme west, on which the fertility, and so the prosperity, of the Empire very greatly depended.

It is proposed in the present place to supply this deficiency.
The principle rivers of the extreme east were the Choaspes, or modern Kerkhah, the Pasitigris or Eulseus, now the Kuran, the Hedyphon or Hedypnus, now the Jerahi, and the Oroatis, at present the Tab or Hindyan.