126 ECONOMIC CONDITIONS (No. 98 .

making twine and rope, and as a substitute for cotton , and silk . A concession has recently been granted to a company in Portuguese East Africa for the exploitation of this tree; and it may well be that in course of time an industry may be developed in the Sudan .

In the Dar Hamar and Dar Homr districts, where wells are few and far between, the inhabitants depend for their water supply in the dry season upon their tebeldi tree water -tanks. These huge stemmed trees are very liable to become hollow , and can easily be scooped out and filled with water. Some are even self-filling during the rains and the water stored in them remains sweet throughout the hot weather . The tebeldi trees are a highly prized form of private property, which is either rented or bought, and their possession often occasions bitter disputes. The populationson the Dar Hamar caravan route make a living by selling to travellers water stored in this way .

In the sudd region ( see p. 75 ) , practically no trees exist, except the ambach (Herminiera elaphroxylon ), which reaches a height of from 10 to 15 ft . It usually grows in several feet of water and forms dense thickets of spiny branches and tangled stems, the latter being sometimes 3 ft . in diameter. The wood when old is very light and corky . The sticks and poles , though light, are fairly durable, and are used by the inhabitants for building and for making rafts, canoes, & c.

The dry ironstone lands of the south-west , sloping upwards from the swamp regions to a height of 2,000 to 3,000 ft . at the Nile -Congo watershed, are covered with heavy bush , the trees in which become finer and more numerous towards the divide . The best of this country extends along the watershed, throughout the whole length of the Bahr el-Ghazal province ,and con tains an almost inexhaustible supply of African mahogany (Khaya senegalensis) and other timber trees, of which the commonest are the lulu or sheabutter tree ( Butyrospermum) --the fruit fruit which produces the