affluent the Sankuru, and sub-affluent the Lo-Mami, offers the most direct route from the Lower to the Upper Congo. Pierre de Brazza has opened the navigation of the Alima, which has already become a busy commercial highway; Jacque de Brazza, Dolisie, Ponel, Van Géle, and Grenfell have penetrated from Opposite sides into the Nkheni, Li-Kwalla, Bunga, and U-Banghi valleys; the same indefatigable Grenfell has ascended the Tchuapa, the Ikelemba, the Lu-Longo, the Mungala, and the Itimbiri.

The least known section of the Congo basin is at present the north-eastern

Fig. 203. — Congo Basin as known in 1887.

region, which of all others offers the greatest geographical interest, and which will probably one day prove to be the most important, for here is situated the water-parting between the Nile and Congo basins. But even here Junker's exploration of the Welle to within 120 miles in a straight line of the Congo valley, no longer leaves any doubt that this-river belongs to the Conga sates and that through it will sooner or later be opened the route to the White Nile.

Thanks to Junker's surveys, a rough calculation may already be made of the actual extent of this vast fluvial system, which according to Léon Metchnikov is