It is navigable by rafts from the junction of its two main branches near the volcanic cone of Koukab, and adds a considerable body of water to the Euphrates.

Below its confluence with this stream, or during the last 800 miles of its course, the Euphrates does not receive a single tributary.

On the contrary, it soon begins to give off its waters right and left, throwing out branches, which either terminate in marshes, or else empty themselves into the Tigris.

After awhile, indeed, it receives compensation, by means of the Shat-el-Hie and other branch streams, which bring back to it from the Tigris, between Mugheir and Kurnah, the greater portion of the borrowed fluid.

The Tigris, on the contrary, is largely enriched throughout the whole of its course by the waters of tributary streams.