OASES, fertile spots in a desert, due to the presence of wells or of under ground water supplies. The best known and most historically famous are those of the Libyan Desert and the Sahara; they occur also in the deserts of Arabia and Persia, and in the Gobi. The French have created many oases in the Algerian deserts by sinking ARTESIAN WELLS (q. v.). The chief vegetation of the African oases is palms—especially date and doom palms; with barley, rice, and millet, when the fertile area is large enough to admit of settled occupation. In the Libyan Desert are the oases of Siwa (where was the temple of Jupiter Ammon) ; in the N., Farafa, Bahriya, and Khargeh (the oasis llta,gna, 120 miles W. of Thebes). In the western Sahara, Tuat, 1,000 miles S. W. of Tripoli, is the best known; in the eastern Sahara are Fezzan, Gadames, Bilma and Air or Asben. See DESERT.
OAT, or OATS (Avena), a genus of edible grasses cultivated extensively in all temperate climates, and though princi pally grown as food for horses largely used as human food. There are about 60 species, the principal of which are A. sativa (the common oat), A. nuda (naked oat, pilcorn, or peelcorn), A. orientalis (Tartarian or Hungarian oat), A. brevis (short oat), A. strigosa (bristle-pointed oat), A. chinensis (Chinese oat), etc. The weight per bushel varies from 32 lbs.
(U. S.) to 40 lbs. (Europe) ; the meal is about half the weight of the oats. The wild oat (A. f atua) is supposed to be the original of all the species, but its native country is unknown. In the calendar year 1918 the oat crop of the United States aggregated 1,538,359,000 bushels. See OATMEAL.