traverse the plains on their way to the Tigris.  The hills themselves—­known now as the Jebel Maklub, the Ain-es-sufra, the Karachok, etc.—­are for the most part bare and sterile.  In form they are hogbacked, and viewed from a distance have a smooth and even outline but on a nearer approach they are found to be rocky and rugged.  Their limestone sides are furrowed by innumerable ravines, and have a dry and parched appearance, being even in spring generally naked and without vegetation.  The sterility is most marked on the western flank, which faces the hot rays of the afternoon sun; the eastern slope is occasionally robed with a scanty covering of dwarf oak or stunted brushwood.  In the fat soil of the plains the rivers commonly run deep and concealed from view, unless in the spring and the early summer, when through the rains and the melting of the snows in the mountains they are greatly swollen, and run bank full, or even overflow the level country.

The most important of these rivers are the following:—­the Kurnib or Eastern Khabour, which joins the Tigris in lat. 37 deg. 12’; the Greater Zab (Zab Ala), which washes the ruins of Nimrud, and enters the main stream almost exactly in lat. 30 deg.; the Lesser Zab (Zab Asfal), which effects its junction about lat. 35 deg. 15’; the Adhem, which is received a little below Samarah, about lat. 34 deg.; and the Diyaleh, which now joins below Baghdad, but from which branches have sometimes entered the Tigris a very little below the mouth of the Adhem.  Of these streams the most northern, the Khabour, runs chiefly in an untraversed country—­the district between Julamerik and the Tigris.  It rises a little west of Julamerik in one of the highest mountain districts of Kurdistan, and runs with a general south-westerly course to its junction with another large branch, which reaches it from the district immediately west of Amadiyeh; it then flows due west, or a little north of west, to Zakko, and, bending to the north after passing that place, flows once more in a south-westerly direction until it reaches the Tigris.  The direct distance from its source to its embouchure is about 80 miles; but that distance is more than doubled by its windings.  It is a stream of considerable size, broad and rapid; at many seasons not fordable at all, and always forded with difficulty.

The Greater Zab is the most important of all the tributaries of the Tigris.  It rises near Konia, in the district of Karasu, about lat. 32 deg. 20’, long. 44 deg. 30’, a little west of the watershed which divides the basins of Lakes Van and Urymiyeh.  Its general course for the first 150 miles is S.S.W., after which for 25 or 30 miles it runs almost due south through the country of the Tiyari.  Near Amadiyeh it makes a sudden turn, and flows S.E. or S.S.E. to its junction with the Rowandiz branch whence, finally, it resumes its old direction, and runs south-west past the Nimrud ruins into the Tigris.  Its entire course,