Dictionary.net

A modification of the Persian wheel used in Egypt for raising water for irrigation purposes. It consists essentially of a vertical wheel to which earthen pots are attached on projecting spokes, a second vertical wheel on the same axis with cogs, and a large horizontal cogged wheel, which gears with the other cogged wheel. The large wheel being turned by oxen or other draught animals puts in motion the other two wheels, the one carrying the pitchers dipping into a well or a deep pit adjoining and supplied with water from a river. The pitchers are thus emptied into a tank at a higher level, whence the water is led off in a network of channels over the neighboring fields. Instead of the wheel, when the level of the water is very low they are attached to an endless rope. The construction of these machines is usually very rude.