The Nile has been the Caucasian’s first and easiest way across the desert to Real Africa before the ocean could be navigated. The Nile basin, moreover, offered to the more sensitive white man elevated areas, oases in a land of malarial fever, wherein he could make some home or settlement, south of the Tropic of Capricorn, not too dissimilar in climate and temperature to the lands of temperate Europe and Asia. From the vantage-ground of Abyssinia, of the Nandi and Ankole plateaux, of the Mediterranean Delta of the Nile, the Caucasian may still direct the education of the Nile Negroes and permeate increasingly these black and bronze-skinned, woolly-haired backsliders from human progress with Caucasian blood, energy, and love of knowledge, till the Nile Negro himself grows interested in the past history of Nile discovery. CHAPTER XXVIII THE GEOGRAPHY OF THE NILE BASIN Early in the geological history of the globe there appear to have been rock-foldings, wrinkles in the earth’s surface in the eastern half of Africa. Sometimes this puckering of the solid crust manifested itself simply in longitudinal strips of raised plateaux of which Abyssinia and the highlands east of the Victoria Nyanza, north and west of Nyasaland, are remains. A sharper wrinkle than others produced the remarkable snowy range of Ruwenzori, perhaps the greatest altitude of the African continent. These lofty plateaux and mountain ranges from Abyssinia on the north to Nyasaland on the south have no doubt in all times attracted an unusually heavy rainfall from the moisture-laden clouds which are blown inland off the Indian Ocean. The rainfall on the Livingstone Mountains and the Nyasa-Tanganyika Plateau drains south and east to the Indian Ocean and west to the basin of the Congo; or into Tanganyika, which is likewise connected with the Congo at the present day.[119] North of the Tanganyika system, however,--that is to say, approximately north of the third degree of south latitude,--the rainfall flows either towards the Mediterranean down the valley of the Nile, or else in a north-northeasterly direction into a string of isolated lakes which apparently at one time communicated with the Gulf of Aden at the mouth of the Red Sea. Supervening on the original wrinkling of the true backbone of Africa (i.e. the elevated ridge which extends from the Nubian Alps to the Cape of Good Hope or at any rate to the Zambezi) came a series of profound volcanic disturbances, elevating, depressing, cracking, and rending the eastern side of this ancient continent. As a rule this volcanic action seems to have proceeded along nearly parallel curved lines, running from the latitudes of the Zambezi River in a north-northeasterly direction. The first and widest of these faults due to volcanic action was seemingly the sinking of the ground between Madagascar and East Africa. A nearly parallel but much narrower rift valley was also formed up the trough of