3rd. In treating this question of Euphrates Valley communication, it seems to be forgotten that not only the circumstances of the Valley itself are changed, but those of all the world of Asia adjoining it.
To understand the present position of Mesopotamia and its adjacent lands, we must consider the history of their ruin. In the days of ancient Rome, not only the shores of the Mediterranean, African as well as European, but also all Western Asia, were a densely peopled empire. Even the lands beyond Roman jurisdiction were full of great cities, from Armenia, through the central plateau of Asia, to the edge of China. Land was everywhere taken up and everywhere of value, while a great surplus population was constantly being pushed out into poorer and still poorer districts by the struggle of life, until hardly a habitable corner of the old world remained unoccupied.
It is not surprising, then, that, with such a necessity for elbow room, the Euphrates and Tigris Valleys were early seized upon, and that at a later date, even poorer regions of the desert were conquered from sterility, and forced into the work of producing food. As long as Babylonia, and the kingdoms which succeeded it, maintained their fertility, these valleys lay on the highway between them and Asia Minor. Even so lately as the twelfth century, Benjamin of Tudela, a Spanish Jew, found numerous large towns still flourishing in Upper Mesopotamia. Palmyra, at that day, was still a commercial city, containing with other inhabitants a population of two thousand Jews. On the Upper Euphrates he mentions five towns, and on the Tigris two or three. It must not, however, for a moment be supposed that these cities owed their wealth in any but a very small measure to agriculture. Palmyra and El Haddr, the two most important, never could have had more than a few cultivated acres attached to them, while the towns on the rivers, though making full use of the alluvial valleys, were essentially commercial. The high road between Aleppo and Bagdad then passed down the Euphrates as far as Kerkesia (Deyr?), whence striking across Mesopotamia to El Haddr, it joined the Tigris at Tekrit. Along this line cities were found at intervals, much as the posting-houses used to be found upon our own highways, and with the same reason for their existence. They gradually died, as these died, with the diversion of traffic from their route. Palmyra and El Haddr, which (to continue the posting-house metaphor) had no paddocks attached to them, were the first to disappear; and then one by one the river towns, which for a time had still struggled on with the aid of their fields, died too. In the thirteenth, and again in the sixteenth centuries, the terrible scourges of Mongul and Ottoman conquests passed over Asia, and swept the regions surrounding Mesopotamia clear of inhabitants. All Western Asia was at this time ruined; and the first result was the abandonment of outlying settlements, which only the stress of over-population elsewhere had ever brought into existence. The Tigris and Euphrates were gradually abandoned, and only the richest districts of Armenia, Kurdistan, and Syria retained. The Ottoman system of misgovernment has done the rest; and now at the present day there is no surplus population eastwards nearer than China, which could supply the deficiency. Until Persia and Armenia are fully occupied, it is idle to expect the comparatively waste lands of Mesopotamia and the river banks to invite immigration. Russia may some day assimilate Asia Minor, and Asia Minor may some day again become populous, but until that is done Mesopotamia must wait.