CAIRO TO KISUMU places, except where the main stream flows through, it is only waist-deep. The evaporation increases at the time of the flood, when more land is covered, so that no matter how much water flows into the swamp, only about the same amount flows out.

The vast masses of floating weeds break up and burst into the channels, and when an obstruction is encountered they pile up on one another just as ice does. In the hot, dry season, when the stems of the papyrus are ten or fifteen feet high, the natives start fires which sweep the region from end to end, destroying all other vegetation. The ashes and burnt stems add to the floating mass, which after a time becomes five or six feet in thickness and almost like peat.

In clearing this Sudd and reopening the channels, the first step is to cut down the vegetation. The sponge-like mass is then cut with long saws into blocks, much as ice is harvested on our ponds. The blocks are pulled out into the current by steel cables attached to the engines on the steamers and float down the stream. An immense deal of this kind of work is going on all along the Upper Nile, for it is only in this way that navigation is kept open.

I have met some of the surveyors who are breaking a way through the Sudd. They describe it as a vast sheet of brilliant green made up of papyrus, feathery reeds, and sword grass. These rise from five to fifteen feet above the water and are broken here and there by patches of ambatch trees and by channels, pools, and lagoons. The greater part of the region has no human inhabitants, especially that along the Bahr el Ghazal.

Big game is to be seen only to the south of the swamp area. There the land is a little higher, and elephants,