eastwards as far as the last spurs thrown out by the mountains of Iran, and westwards to the foot of the sandy heights which terminate the plateau of Arabia. "The whole lower part of the valley has thus been made, since the commencement of the present geological period, by deposits from the Tigris, the Euphrates, and such minor streams as the Adhem, the Gyndes, the Choaspes, streams which, after having long enjoyed an independent existence and having contributed to drive back the waters into which they fell, have ended by becoming mere feeders of the Tigris."[1] We see, therefore, that when Chaldæea received its first inhabitants it was sensibly smaller than it is to-day, as the district of which Bassorah is now the capital and the whole delta of the Shat-el-Arab were not yet in existence.
§ 2.-Nature in the Basin of the Euphrates and Tigris.
The inundation of the Nile gives renewed life every year to those plains of Egypt which it has slowly formed, and so it is with the Tigris and Euphrates. Lower Mesopotamia is entirely their creation, and if the time were to come when their vivifying streams were no longer to irrigate its surface, it would very soon be changed into a monotonous and melancholy desert. It hardly ever rains in Chaldæea.[2] There are a few showers at the changes of the season, and, in winter, a few days of heavy rain. During the summer, for long months together, the sky remains inexorably blue while the temperature is hot and parching. In winter, clouds are almost as rare; but winds often play violently over the great tracts of unbroken country. When these blow from the south they soon lose their warmth and humidity at the contact of a soil which, but a short while ago, was at the bottom of the sea, and is, therefore, in many places still strongly impregnated with salt which acts as a refrigerant.[3] Again, when the north wind comes down from the snowy summits of Armenia or Kurdistan, it is already cold enough, so that, during the months of December and January, it often happens that the
