22.

The contracted shape of Mesopotamia extends far in length, and somewhat resembles a ship. The Euphrates forms the larger part of its boundary. The distance from Thapsacus to Babylon, according to Eratosthenes, is 4800 stadia, and from the (Zeugma)526 bridge in Commagene, where Mesopotamia begins, to Thapsacus, is not less than 2000 stadia.