I have been much interested in the irrigation works of the past. The whole of the Nile valley above Cairo is cut up into a series of basins. For six hundred or seven hundred miles north of this point the valley slopes very gradually and, in order to save the water, dikes have been made across it and embankments run parallel with the river, turning the whole country into a series of basin-like terraces, each containing from five thousand to fifteen thousand acres. These basins, which are often subdivided, are so connected that the water flows from one to the other until it finally passes out of the lower basin back into the Nile. When the floods come, the lowest basins are filled first and then those higher up, until at last all have become great ponds and Egypt is one vast inland sea cut up by the embankments and islands upon which the villages stand. There are many such systems of basins in Upper Egypt, some large and some small. There are also basins higher up and closer to the river which are filled with _sakiebs_ or _shadoofs_. When I tell you that the fall of this valley from here to Cairo is only seven inches to the mile you will see how carefully these basins must be graduated in order to take advantage of the flow of the river. They have to be so constructed that the water can be drained off as rapidly as it is let on. As I have already said, the Abyssinian mud contains a great quantity of salts, and it is just as bad to have too much of it as too little. If the land is over-watered the salts dissolve from the soil, the over-soaked land becomes wormy, and the crops are often sown too late. The red water, or that containing the silt, is allowed to stand just about forty days. During this time it drops a great deal of sediment and furnishes enough moisture for the crops. But the Aswan Dam has so regulated the river flow that the Egyptian farmer is far less at the mercy of low Niles or high Niles than in the past. The dam is one of the wonders of modern Egypt. It is in full sight of me as I sit here on the left bank of the Nile, with the desert at my back. It looks like a great stone viaduct crossing the rocky bed of the river, joining the stony hills which wall the Nile on both sides, and holding back a portion of its mighty waters. It is a huge granite barrier a mile and a quarter long. There is now a roadway guarded by walls on its top, and there is a miniature railway, the cars of which are pushed by men from one end to the other. The dam serves as a bridge as well, and donkeys, camels, and men are allowed to pass over it from bank to bank. I crossed on the car at a cost of twenty-five cents, my motive power being two Arab boys who trotted behind.