72 [No. 98 ECONOMIC CONDITIONS .

> and the Bahr el-Arab, all of which, like the Jur, have their sources in the Nile-Congo watershed. · The Jur is navigable by river steamers as far as Wau ( 160 miles) during the season of high water, between July and October, but even then with difficulty in the narrows, where the passage is choked with masses of floating vegetation . For the remainder of the year the channel iscompletely blocked . Small steamers and boats can proceed beyond Wau for a considerable distance during the season of high water, and can also under favourable conditions ascend the tributaries of the Jur, the Sueh and the Wau, for 30–40 miles .

The Sobat or Bahr el-Asfar (yellow river ), of whicii the section from the source to the confluence of the Pibor is known locally as the Baro, rises in the Abyssinian highlands. It is at its lowest about the end of April. Navigation in flood time ( June to December ) begins at Gambela, 100 miles from the source of the river, and 355 miles from its confluence with the Nile . Forty miles below Gambela on the left bank is Itang , and 80 miles down -stream is the con fluence of the Khor Adura , a torrential stream , navi gable for a short time during the flood season . Fifteen miles farther down is the mouth of the Pibor ( left bank ), and upon the same bank, nearly 30 miles lower, is Nasser Post . The next important place is Abwong ( left bank ) , another 107 miles on ; 71 miles farther is the American Mission Post at Doleib Hill , only 6 miles from the confluence of the river with the White Nile . The Sobat serves as the main waterway for Abyssinian trade via Gambela .

The Pibor, the chief tributary of the Sobat , rises in the swampy plains of the Mongalla province and flows northward . At Pibor Post (Fort Bruce) , 182 miles from its mouth , it is joined by the Veveno, and at Akobo Post by its chief affluent, the Akobo , which - rises in the Abyssinian hills, and has a length of about 200 miles . Thirty -three miles below Akobo Post , and the same distance from its junction with the Sobat, the Pibor is joined by another large affluent, the Gillo 7