The route by the Nile, the canal of Neco, and the Red Sea, was decidedly inferior, more especially on account of the dangerous navigation of that sea, but also because it was circuitous, and involved a voyage in the open ocean of at least twice the length of the other.
Again, Assyria lay almost necessarily on the line of land communication between the north-east and the south-west.

The lofty Armenian mountain-chains--Niphates and the other parallel ranges--towards the north, and the great Arabian Desert towards the south, offered difficulties to companies of land-traders which they were unwilling to face, and naturally led them to select routes intermediate between these two obstacles, which could not fail to pass through some part or other of the Mesopotamian region.
The established lines of land trade between Assyria and her neighbors were probably very numerous, but the most important must have been some five or six.

One almost certainly led from the Urumiyeh basin over the _Keli-shin_ pass (lat.

37 deg., long.

(45 deg.