The staple crops of the oasis are dates, rice, wheat, and barley, while for fodder large quantities of lucerne are grown. It seems at first sight a curious anomaly that in an arid region, where water is so scarce and precious a commodity, rice should be grown as the summer crop. Few, if any, plants require such an abundance of water as rice, which from the time of sowing to that of reaping has to be continually irrigated by fresh water, the fields being, indeed, during the whole period that the crop is on the ground, in a constant state of saturation. Rice does not thrive in stagnant water, and it is noticeable that the best crops in the oasis are raised on lands which have a decided slope, and over which fresh water can be kept constantly running. The proper irrigation of a rice-field is a matter of no small difficulty, and the ingenious manner in which the oasis cultivator lays out his irrigating channels and subdivides them by means of notched weirs, so as to insure every portion of the crop getting a continuous supply of fresh water, is well worthy of close examination. In the Nile Delta, according to Sir William Willcocks,[13] rice requires about twice as much water as the other commonly-grown crops, but in the oases I do not think I am mistaken in saying that it needs three times as much as any other grain. Rice appears to have been grown from time immemorial, and certainly at the present day the inhabitants would as soon think of giving up their date-trees as of replacing it by any other crop. Now, however, that facilities exist for the export of farm-produce to the Nile Valley markets, it will be interesting to observe whether rice will to any extent be replaced by more valuable crops. In Upper Egypt the summer crop is largely durra millet (sorghum), but this plant does not thrive in the oasis, though whether on account of an uncongenial soil or owing to unsuitable climatic conditions I am unable to say. It has frequently been tried—in fact, small areas are annually planted, but never produce crops—at any rate, in the northern part of Kharga—in any sense comparable with those of the Nile Valley. The very fact that durra cannot be satisfactorily grown suggests a probable reason why rice, the least valuable of the Egyptian cereals, and the one requiring most water, is so universally grown in Northern Kharga. Rice, as is well known, will grow on land containing a proportion of salts which would be injurious, or even fatal, to the majority of crops, and will at the same time exercise a beneficial and cleansing effect on such land. The growing of rice may therefore have come about through the actual necessity for a periodical cleansing of land, which would otherwise have become salted to a sufficient extent to adversely affect other crops grown on the same ground. At the present day, barley and wheat alternate with rice.