Page:Popular Science Monthly Volume 62.djvu/557

Rh by strict regulations. Thus, two years ago, when the Nile was below the average in summer discharge, it was decreed in Upper Egypt that the 'lifting machines,' which include the handoff, or bucket-and-pole system, and the sakieh, or oxen-driven chain of buckets, should be worked not more than from five to eleven consecutive days, and stop the following nine to thirteen days, between the middle of April and the middle of July; and the order in which the different districts were to receive a supply was carefully specified, so that, as far as possible, every crop should get watered once in about three weeks. When it is remembered that a single watering of an acre of land means, where shadoofs are concerned, raising by manual power about 400 tons of water to varying heights up to 25 feet, and that four or five waterings

are required to raise a summer crop, it will be seen what a vast amount of human labor is saved throughout the world by the providential circumstance that in ordinary cases water tumbles down from the clouds, and has not, as in Egypt, to be dragged up from channels and wells. Shadoof work, under average conditions, involves one man's labor for at least one hundred days for each acre of summer crop; so that even at 6d. per day for labor, the extra cost of cultivation due to the absence of rain would amount to 50s. per acre.

The great Nile Reservoir and Dam at Aswan, the Barrage at Asyut, and various supplementary works in the way of distributing canals and regulators, are designed with the object of mitigating the evils