[Illustration: 089.jpg AN EGYPTIAN SAKIA (WELL) SHOWING METHOD OF PROCURING WATER FOR IRRIGATION.] In any year the portion not watered by the river was invaded by the sand: from the lush vegetation of a hot country, there was but one step to absolute aridity. At the present day an ingeniously established system of irrigation allows the agriculturist to direct and distribute the overflow according to his needs. From Gebel Ain to the sea, the Nile and its principal branches are bordered by long dykes, which closely follow the windings of the river and furnish sufficiently stable embankments. Numerous canals lead off to right and left, directed more or less obliquely towards the confines of the valley; they are divided at intervals by fresh dykes, starting at the one side from the river, and ending on the other either at the Bahr Yusuf or at the rising of the desert. Some of these dykes protect one district only, and consist merely of a bank of earth; others command a large extent of territory, and a breach in them would entail the ruin of an entire province. These latter are sometimes like real ramparts, made of crude brick carefully cemented; a few, as at Qosheish, have a core of hewn stones, which later generations have covered with masses of brickwork, and strengthened with constantly renewed buttresses of earth. They wind across the plain with many unexpected and apparently aimless turns; on closer examination, however, it may be seen that this irregularity is not to be attributed to ignorance or caprice. Experience had taught the Egyptians the art of picking out, upon the almost imperceptible relief of the soil, the easiest lines to use against the inundation: of these they have followed carefully the sinuosities, and if the course of the dykes appears singular, it is to be ascribed to the natural configuration of the ground. Subsidiary embankments thrown up between the principal ones, and parallel to the Nile, separate the higher ground bordering the river from the low lands on the confines of the valley; they divide the larger basins into smaller divisions of varying area, in which the irrigation is regulated by means of special trenches. As long as the Nile is falling, the dwellers on its banks leave their canals in free communication with it; but they dam them up towards the end of the winter, just before the return of the inundation, and do not reopen them till early in August, when the new flood is at its height. The waters then flowing in by the trenches are arrested by the nearest transverse dyke and spread over the fields. When they have stood there long enough to saturate the ground, the dyke is pierced, and they pour into the next basin until they are stopped by a second dyke, which in its turn forces them again to spread out on either side. This operation is renewed from dyke to dyke, till the valley soon becomes a series of artificial ponds, ranged one above another, and flowing one into another from Grebel