YEMEN ( Yaman), an extensive region forming the south western portion of Arabia. The limits of power exercised by the 'various rulers are not clearly defined, but Yemen includes the province of Asir and reaches in the north towards the Hejaz and the Nejd. On the east its limits merge with the desert, while on the south they abut on Hadhramaut. Yemen may be looked upon as possessing three centres: the British protectorate of Aden (q.v.) in the south; the domains of the Imam Yahya, whose capital is Sana (q.v.) and those of the Idrisi Seyyid Ali Mohammed, whose capital is Sabia I I' N., 37' E.), and whose influence stretches down the coast to Hodeida (q.v.).
The Imam Yahya is Imam of Yemen proper, and his lands include those abandoned by the Turkish power in 1918 and con sequently the limits of his power are in line with those of the Anglo-Turkish boundary of 5902-4. He governs an area of some 75,00o sq.m., with a population between 2,000,000 and 3,000,000.
Ptolemy and the ancient geographers in general include the whole peninsula under the name of Arabia Felix (eboatmcov), in which sense they translate the Arabic Yemen, literally "right hand," for all Arabia south of the Gulf of Aqaba was to the right from their standpoint of Alexandria; the Mohammedan geog raphers, however, viewing it from Mecca, confine the term to the regions south of Hejaz, including Asir, Hadhramaut, Oman and part of southern Nejd. Yemen occupies the uptilted edge of a block of ancient land forming Arabia.
The uptilted edge of the old block is known as the Jibal or highlands of Yemen, with an average height of 9,000 ft., though many summits exceed io,000 f t., e.g., Jebel Manar (10,565 ft.).
The principal town of the Jibal is Ta'iz (pop. about 4,000). It was formerly a large city, and from its position in the centre of a comparatively fertile district at the junction of several trade routes it must always be important. Some 3o m. further north are the small towns of Ibb (6,700 ft.) and Jibla, about 5 m.
apart, typical hill towns with their high stone-built houses and paved streets. Manakha produces the best coffee in Yemen. An other group of hill towns lies still further north in the mountain mass between the Wadi Maur and Wadi La'a, where the strong holds of Dhafir, Afar, Haja and Kaurkaban have long been known for their independence. The last-named was once a city of 20,000 inhabitants, and the capital of a small principality which preserved its independence during the earlier Turkish occupation between 1536 and 163o. The lowland strip of Yemen is known as the Tehama and is hot and generally sterile. The lowland strip is from 20 to 30 m. wide. There are oases, however, near the foot of the mountains, fertilized and irrigated by hill streams and supporting many large villages and towns. The most important of these are Abu Arish, Bet el Fakih and Zubed in the western Tehama, the latter a town of 20,000 inhabitants. Hodeida (q.v.) and Aden (q.v.) are the only ports of commercial importance, while Mokha is the old centre of the coffee trade. Beyond the crest of the uptilted edge of the old block stretches the third natural region of Yemen—the great desert. As it lies entirely to the east of the high crest, it has a smaller rainfall than the Jibal. Its general character is that of a steppe increasing in aridity towards the east where it merges in the desert, but broken in places by rocky ranges, some of which rise 2,000 ft. above the general level, and which in the Hamdan district north of Sana show evidence of volcanic action. It is intersected by several wadi systems, of which the principal are those in the north uniting to form the Wadi Nejran, in the centre the Wadi Kharid and Shibwan running to the Jauf, and in the south the Wadi Bana and its affluents draining to the Gulf of Aden. The plateau has a gradual fall from the watershed near Yarim, 8,500 ft. above sea level, to less than 4,000 ft. at the edge of the desert.