TIGRIS, a river of Asiatic Turkey, in the pashalies of Diarbekir, Mosul, and Bagdad. It rises by two principal sources in the range of Anti-Taurus in Armenia, not far from those of the Euphrates, and flows first for a short distance N.E., then S.E. to Diarbekir. From this town it flows eastwards, parallel to Anti-Taurus, for 105 miles, till its confluence with the Bitlis from the left. Here its direction becomes S.E. as far as Mosul and the ruins of
Nineveh, shortly below which it receives the Upper or Great Zab. At this point the Tigris takes a more direct southerly course as far as Bagdad, receiving from the northeast the Lower or Lesser Zab. At Bagdad its distance from the Euphrates is only 30 miles; and the two rivers flow for some distance nearly parallel. A little way below Bagdad the Tigris receives the Diyala, and about the same point a canal joins it with the Euphrates. About 80 miles farther down it takes a curve to the east, and finally, after a total course of 1150 miles, joins the Euphrates at Korna, forming together with it the Shat-ul-Arab. (See EUPHRATES.) Between Mosul and Bagdad, a distance of about 220 miles, the average breadth of the river is 200 yards; but it varies considerably in different seasons, attaining its greatest height about the end of May. The neighbouring country is but thinly peopled and only partially cultivated, but it contains some extensive tracts of rich pasture land. The Tigris is navigable for rafts as far as Mosul, and at certain seasons as far as Diarbekir. Goods are conveyed down the stream, sometimes with great rapidity, on large rafts supported on inflated skins.