This large and celebrated river, which flows along the boundaries of the Turkish and Persian empires, has its rise in the mountains of Armenia, about fifty miles to the north-west of the valley of Diarbekir, and fifteen to the east of the source of the Euphrates. It derives its ancient Persian name of Tir or Teer, the arrow, from the swiftness of its stream, its average rate being about seven knots an hour. Not being within the range of the periodical rains, its waters begin to rise in April, with the melting of the winter snows in the mountains; its second rise takes place in the beginning of November, with the setting in of the winter rains. The spring inundation is however the greatest, and it is then only that a complete inundation covers the land, and that by the conflux of the waters of the Tigris and the Euphrates. Bagdad stands like an island in the midst of a wide ocean. To the annual overflowing of these two streams the country is indebted for its fertility.

The Tigris is not navigable above sixty miles beyond Bagdad for vessels of more than twenty tons burden; though the intercourse is still maintained much higher up, by a kind of float called a kelek, which was used in ancient times, and which carries both passengers and merchandise, chiefly corn and copper, from Mosul to Bagdad. It is singularly well adapted for its purpose, consisting of a raft in the form of a parallelogram. The trunks of two large trees crossing each other are the foundations of its platform, which is composed of branches of osier twigs ingeniously fastened to the stems below. To this light bottom are attached sheep-skins filled with air, and on these the floor is laid. These vessels are floated down to Bagdad with the current, where, after their cargoes are disposed of, they are taken to pieces and sold, it being impossible to return with them against the stream.

Between Bagdad and Korna the Tigris is about 200 yards wide. At the latter place it joins the Euphrates; and the united stream, under the new name of Shat-el-Arab, falls into the Persian Gulf. This river was particularly famed in antiquity; and many of the greatest cities, as Nineveh, Seleucia, and Ctesiphon, were built upon its banks. The Tigris and the Euphrates, though they rise within fifteen miles of each other, soon separate, and running parallel, but at a greater distance, enclose the extensive province of Algezira. At Bagdad they again approach within thirty miles, and afterwards separate, forming the rich district of Irak Arabi.