filled up this gulf with their alluvial deposit, aided by the Adhem, the Diyaleh, the Kerkha, the Karun, and other rivers, which at the end of long independent courses became tributaries of the Tigris.  The present beds of the two rivers, connected by numerous canals, at length meet near the village of Kornah and form one single river, the Shatt-el-Arab, which carries their waters to the sea.  The mud with which they are charged is deposited when it reaches their mouth, and accumulates rapidly; it is said that the coast advances about a mile every seventy years.** In its upper reaches the Euphrates collects a number of small affluents, the most important of which, the Kara-Su, has often been confounded with it.  Near the middle of its course, the Sadjur on the right bank carries into it the waters of the Taurus and the Amanus, on the left bank the Balikh and the Khabur contribute those of the Karadja-Dagh; from the mouth of the Khabur to the sea the Euphrates receives no further affluent.  The Tigris is fed on the left by the Bitlis-Khai, the two Zabs, the Adhem, and the Diyaleh.  The Euphrates is navigable from Sumeisat, the Tigris from Mossul, both of them almost as soon as they leave the mountains.  They are subject to annual floods, which occur when the winter snow melts on the higher ranges of Armenia.  The Tigris, which rises from the southern slope of the Niphates and has the more direct course, is the first to overflow its banks, which it does at the beginning of March, and reaches its greatest height about the 10th or 12th of May.  The Euphrates rises in the middle of March, and does not attain its highest level till the close of May.  From June onwards it falls with increasing rapidity; by September all the water which has not been absorbed by the soil has returned to the river-bed.  The inundation does not possess the same importance for the regions covered by it, that the rise of the Nile does for Egypt.  In fact, it does more harm than good, and the river-side population have always worked hard to protect themselves from it and to keep it away from their lands rather than facilitate its access to them; they regard it as a sort of necessary evil to which they resign themselves, while trying to minimize its effects.***

* This fact has been established by Ross and Lynch in two articles in the Journal of the Royal Geographical Society, vol. ix. pp. 446, 472.  The Chaldaeans and Assyrians called the gulf into which the two rivers debouched, Nar Marratum, or “salt river,” a name which they extended to the Chaldaean Sea, i.e. to the whole Persian Gulf.

** Loftus estimated, about the middle of the last century, the progress of alluvial deposit at about one English mile in every seventy years; H. Rawlinson considers that the progress must have been more considerable in ancient times, and estimates it at an English mile in thirty years.  Kiepert thinks, taking the above estimate as a basis, that in the sixth century