The mode of estimating the revenue in Nubia is not from a certain extent of ground, like the Syrian and Egyptian Fedhan, but from every Sakie, or water-wheel employed by the natives, after the inundation, and during the summer, for the purposes of irrigation; the same mode prevails on the banks of the Nile as far as Sennaar. In poor villages one Sakie is the common property of six or eight peasants; but the wealthier inhabitants have several. The number of water-wheels between Assouan and Wady Halfa, or between the first and second cataract, is from six to seven hundred. The ground watered by one Sakie, which requires the alternate labour of eight or ten cows, comprises from three to five Egyptian Fedhans. In fruitful years, the winter wheat and barley irrigated by one wheel yields from eighty to one hundred Erdebs (twelve to fifteen hundred bushels); the proportions sown of these grains are generally one fourth wheat and three fourths barley.[66] The rate of taxation is different in different places; thus at Wady Halfa, each Sakie pays annually six fat sheep, and six Egyptian Mouds, or measures of Dhourra. In Mahass, the Malek, or king, takes from every wheel six sheep, two Erdebs, (twenty-six bushels) of Dhourra, and a linen shirt. The governors also take from every date tree two clusters of fruit, whatever may be the quantity produced, and levy a duty upon all vessels that load dates at Derr.[67] But the whole system of taxation is extremely arbitrary and irregular, and poor villages are soon ruined by it, from their inability to resist the exactions made upon them, while the richer ones pay much less in proportion, because the governors are afraid of driving the inhabitants to acts of open resistance. The Kashefs derive also a considerable income from their office of judges; the administration of justice being a mere article of merchandize.