North of the Fayum the Nile flows on to Cairo, where the narrow water way allowed to its course by the two lines of cliffs widens, and the cliffs recede to the right and left. There is thus space for the waters to spread and ramify over the alluvial plain. Nearly all this portion of Egypt has been covered by the sediment of the Nile, and from the earliest times there have been numerous distinct branches or channels of the river running out by separate openings into the sea. As several of these branches have been tapped to a great extent for irrigation, all except two have ceased to be true outlets of the Nile. In the Greek period there were seven mouths and several [...Greek...], or "false mouths." The two remaining mouths are those of Rosetta and Damietta, and these were always the most important of the number. They branched off formerly close to the present spot where Cairo stands, a little below Memphis; but during two thousand years the fork has gradually shifted to about thirteen miles lower down. The triangular space enclosed by these two branches and the sea-coast was called by the Greeks the delta, on account of the likeness in shape to the Greek letter of that name A. At the head, or apex, of the triangle stands the famous barrage, or dam, begun in 1847 by Mehemet Ali, for the twofold purpose of reclaiming many thousand acres of waste land, and of regulating the discharge and the navigation through the Delta. The idea was originated by a Frenchman in his service named Linant Bey. This engineer desired to alter the course of the river and build a weir at a point farther to the north, where the contour of land seemed to favour the design more than that of the present locality. Mehemet Ali thought his plans too costly, and accepted in preference those of Mougel Bey. Unexpected difficulties were encountered from the very beginning. Mehemet was exceedingly anxious to hurry the work, and Mougel Bey had only made a beginning, when an exceptionally high Nile carried away all the lime in the concrete base. Mehemet Ali did not live to see the completion of this work. The object, could it have been realised, was to hold up the waters of the Nile during the eight months of the ebb, and thus keep them on a level with the soil, and at the same time to supply Lower Egypt with an amount of water equal to that which came down during flood-time. It was hoped to cover the very large expenditure by the additional land which it was expected would come under irrigation, and by doing away with the primitive _shadoofs_ and setting free for productive enterprise the numerous army of the agricultural labourers who spent the greater part of their time in slowly raising up buckets of water from the Nile and pouring them into the irrigating channels. [Illustration: 240b.jpg Harbour at Suez]