mortar, they are kept in perfect repair.  Reservoirs filled with water from the two rainy seasons, supply the irrigation channels.[1271] In the narrow valleys of the Nejd plateau in central Arabia and on the mountain slopes of Oman are found the same irrigated gardens and terraced plantations.  This laborious tillage underlay the prosperity of the ancient Sabaean monarchy of Yemen, as it explains the population of 35,000 souls who occupy the modern capital of Sanaa, located at an altitude of 7600 feet (2317 meters).[1272]

[Sidenote:  In the Himalayas.]

Turning eastward, we find terrace agriculture widely distributed in Himalayan lands.  The steep mountain sides of the Vale of Kashmir are cultivated thus to a considerable height.  The terraces are irrigated by contour channels constructed along the hillsides, which bring the water for miles from distant snow-fed streams.  Their shelf-like fields are green with fruit orchards and almond groves, with vineyards and grain fields.[1273] The terraced slopes about the Himalayan hill-station of Simla (elevation 7100 to 8000 feet) feed the summer population of English, who there take refuge from the deadly heat of the plains.  The mountain sections of the native states of Nepal and Bhutan present the view of slopes cut into gigantic stairs, each step a field of waving rice kept saturated by irrigating streams from abundant mountain springs.  Farther north, where Himalayas and Hindu Kush meet, terrace agriculture is combined with irrigation in the high Gilgit valleys, and farther still along that mere gash running down from the Pamir dome, called the Hunza Valley.  Here live the once lawless robber tribes of the Hunzas and Nagaris, whose conquest cost the British a dangerous and expensive campaign in 1892, but whose extensive terraces of irrigated fields and evidences of skillful tillage gave the whole country an appearance of civilization strangely at variance with the barbarous character of its inhabitants.[1274]

[Sidenote:  In Tibet and China.]

North of the outer Himalayan range, near the sources of the Indus and Sutlej rivers in Ladak or Western Tibet, this same form of cultivation has been resorted to by the retarded and isolated Mongolian inhabitants.  Here at an altitude of 11,000 feet or more (3354 meters), along mountain ranges of primitive rock yielding only a scant and sterile soil, terraces are laboriously constructed; their surfaces are manured with burnt remains of animal excrements, which must first serve as fuel in this timberless land before they are applied to the ground.  In this stronghold of Buddhism almost every lamasery has its terraced fields yielding good crops of grain and fruit.[1275] In the densely populated Sze Chuan province of western China, cultivation has climbed from the fertile basins of the Min and upper Yangtze rivers far up the surrounding mountains, where it is carried on terraces to the foot of vertical cliffs.[1276] Farther north where the mountain province of Shensi occupies the rise of land from the Chinese lowlands to the central highlands of Asia, terraces planted with wheat or other grains cover the mountain slopes.[1277]