Obstacles. 3

Navigability (Upstream). From Omdurman upstream to Lado, practically 1,000 miles, the only obstacles to navigation at any time

of the year are :—

1. Scarcity of fuel (for steamers). 2. The sudd.

3. Sandbanks.

1. In 1875 Gordon wrote :—" Navigation from Lado to Fuel. Khartum is almost impossible ; firewood is scarce and becomes more so every year; there are numerous sand- banks."

All travellers concur in the difficulties of procuring sufficient fuel for the steamers, especially in the sudd

districts, where trees are scarce, and the difficulties in

getting at them are very great.

The only method would appear to be to institute numerous wood stations along the banks from which to

replenish the steamers or the fuel«nuggers which they tow, and to moor floating wood stations at intervals in the sudd reaches.

2. The sudd is formed as follows :— Sudd, The Bahr ez Zeraf , the lower course of the Bahr el Jebel, and the Bahr el Ghaza], are all liable to become choked with masses of vegetation or grass barriers formed by floating islands of weeds, &c. The riverbed then assumes the appearance of a vast marsh, which, if neglected, becomes impracticable for navigation. As Colonel Gordon states, below Regaf the Nile spreads out into lakes ; on the edge of these an aquatic plant with roots 5 feet long flourishes.

The natives burn the tops when dry, the ashes form a mould, fresh grasses grow till it becomes like terra firma. The Nile rises and floats out these masses ; they come down to a curve in the river, and then stop, and so the river becomes at length blocked. These barriers have been cut away many times ; Sir S. Baker cut his way through 80 miles of sudd, but unless the river is kept open by constant navigation, it is always liable to reform. In September, 1880, Gessi Pasha suffered great hardships on the Bahr el Ghazal during his voyage back to Khartum. He found a grass barrier in front, and a strong wind

(386) B 2