e 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 before our era the fore-shore came from about
ten to twelve German miles (47 to 56 English) higher up than
the present fore-shore. G. Rawlinson estimates on his part
that between the thirtieth and twentieth centuries B.C., a
period in which he places the establishment of the first
Chaldaean Empire, the fore-shore was more than 120 miles
above the mouth of Shatt-el-Arab, to the north of the
present village of Kornah.

*** Fr. Lenormant has