860 NOETH-KVST AFEICA. Hefi and nili lands. The latter, as indicated by the name itself, comprise all those tracts that would be flooded by the annual inundation but for the retaining dykes, as well as those reached through infiltration by the deep waters derived either from the main stream or from natural or artificial channels excavated at a slight depth below the surface of the ground. The lowest dykes derive their waters at a depth of about 13 feet below the cultivated lands, and are flushed only during the period of the inundations, remaining dry for the rest of the year. During the last century the wliole of Egypt was watered exclusively by means of basins disposed at different elevations along both banks of the river, and receiving their supplies through the nili canals, and over three-fourths of the cultivated tracts in Upper Egypt are subject to the same method of irrigation. The sefi, that is, " summer " canals, all of recent origin, are excavated below the mean low-water level from 26 to 30 feet below the surface, so that they are reached by the stream even at the very height of the dry season. In Upper Egypt they are disposed parallel with the river and at a very slight incline, so as to bring them at once to the level of the lands to be irrigated. But in Lower Egypt, from which the system of irrigating basins has entirely disappeared, the sefi canals remain everywhere at a lower level than the fields, to which the water must be raised by means of steam-engines, sakiehs, or shadufs. One of these sefi canals is the famous Mahmudieh channel, which derives its water from the Nile in order to irrigate the tracts skirting the desert as far as the city of Alexandria, and which serves at the same time as a great navigable highway. But having become partly choked by the mud, it is no longer deep enough to admit a regular current, hence has to be partly filled by means of steam-engines established at Atfeh, on the Rosetta branch of the Nile. The Damietta branch also feeds numerous summer canals, thanks to its relatively high elevation above the plains of the delta. The sefi system was first introduced under Mohammed AH, when the cultivation of Jumel cotton was begun. By this method are still almost exclusively raised the larger and more important crops, such as sesame, sugar, and cotton, which are thus watered for three months continuously before the period of the ordinary inundation. So it happens that the small holdings have no share in the benefits reserved for the large estates irrigated during the period of low water. The high State functionaries and rich money-lenders alone derive any advantage from growing these larger industrial crops. Yet they are not the only contributors to the maintenance of the works, the cost of which is enormous, owing to the mud constantly accumu- lating in the ditches and gradually filling them up in many places. A single year would suffice to convert a sefi canal into a simple nili channel but for the numerous gangs of fellahin employed for weeks and months together on the work of excavation. The sefi canals taken collectively represent a quantity of deposits about half as much again as that of the Suez Canal, and every year the amount of mud and earth required to be again displaced to keep open the dykes is not less than one-third of the original deposits.
