Where there are no mounds, husbandry is carried on to some extent. In the eastern corner, in the angle of the outer wall, the overflow of water collects in a lake during the period of irrigation. But even in this low quarter of the city there were once dwellings, which the course of centuries has covered with the enveloping shroud of the shifting and levelling sands. IV THE EUPHRATES AND ITS COURSE Although the Euphrates lies for the greater part of the year shrunken in its arid bed (Fig. 7), yet at the commencement of our expedition its full flood covered the entire bed from 100 to 200 metres wide (Fig. 8). In comparison with its boisterous relative the Tigris, it appears very sluggish, but it entirely fulfils its mission as an alluvial river. At each bend it removes the superfluous matter from one bank to deposit it as a valuable asset on the other bank lower down, and by this assiduous and steady work it gradually alters its course. As far back as the time of Nebuchadnezzar its general direction was from north to south, but not precisely as to-day. Its course took it close by Babil, which commanded its entrance into the city, and it certainly washed the west front of the Kasr exactly where the village of Kweiresh stands to-day. From here we can trace its ancient course in the long, shallow depression that runs close under Amran. Here we have found the stone bridge mentioned by Greek authors as spanning the river. The Kasr lay then, as now, on the left bank of the Euphrates, but there was a period under the Persian and Greek kings when it lay on the right bank, and its north, east, and south sides were more or less washed by those waters. It is easy to understand that the continuous shifting of the river must have altered both its bed and its level. To-day, when very little water comes into the river, ground water is reached 1 or 2 metres lower than 10 years ago, when it was at about the same level as in the time of Nebuchadnezzar, but it must have been considerably lower under the first kings of Babylon, when the houses in Merkes were built, as these now stand below water-level. [Illustration: FIG. 7.—The Euphrates in 1911. ] [Illustration: FIG. 8.—The Euphrates, seen looking north from the Expedition House in 1907. ]