"كتيّب الجزيرة العربية المُعد تحت إشراف القسم التاريخي لوزارة الخارجية – رقم ٩٠". [‎٨‎٣] (١٤٨/٩٨)

ArabiJ METHODS OF CULTIVATION
83
the wadi Rumma, and that of Riad is similarl}
traceable to the damp subsoil of the wadi Hanifa.
From low wadis water is diverted directly for irri
gation purposes by the cutting of channels in the
banks. The oases of Nejran and Jauf (in Yemen) are
thus fertilised by inland wadis, and the Semail and
many other coastal valleys by wadis leading to the sea.
Wadi Tiban, in the Aden Protectorate, loses at one
part of its course the whole of its water, but receives
it again farther on. The main Hadhramaut wadi
similarly loses all its water (including its supply from
considerable underground reservoirs) a hundred miles
before it reaches the sea.
(2) Wells worked by animal traction. In many
cases water is raised from deep wells for irrigation
purposes by this means. The famous well-pit of El-
Haddaj supplies water to the whole Teima oasis. This
well measures 50 feet across, and the water, which is
reached at a depth of 50 ft., is raised in leathern
buckets by means of 60 draw-wheels mounted on frames
and worked by camels. It then enters troughs, from
which it is distributed by means of little runnels. At
Kheibar oasis, where the supply is more limited, the
cultivators have the right to irrigate with the public
wateir once a week, a fixed time being appointed for
each. Smaller installations are often worked by
donkeys. The wells at Riad are from 40 to 80 ft.
deep, and those at Harik and Jebel Shammar 100 ft.
Oil pumps could be substituted for animal traction if
petroleum could be obtained easily and cheaply.
(3) Rain Cisterns. The famous tanks of Aden,
now insufficient even for the city's drinking supply,
were possibly intended originally for irrigation pur
poses. In Hadhramaut and Yemen, especially in the
coffee-growing districts, cisterns are built wherever it
is possible to collect rain or surface water. As the
rainfall in Yemen is greater than in any other part of
Arabia, a considerable quantity is procured, but a more
comprehensive and economical system would give the
district a better prospect of development. The use of
[285—8] G 2