34 
THE TANGANYIKA PROBLEM. 
ice-capped as it is. It is only comparatively recently that the 
existence of these interior heights has become known, and 
it is only quite recently that the conception of a long axial 
range in Africa, bearing the same relation to that continent 
that the Andes do to South America, has begun to be 
appreciated. It is indeed to Mr. Scott Elliot* that we owe 
the first clear apprehension of this fact, and it is such a very 
important fact in all questions of African physiography, that 
I shall attempt in this, as in a former work,f to emphasise 
the appreciation of it by giving the mountain chains a 
special name and by speaking of them as “ The Great 
Central African Range.” 
The main river systems of Africa flow from the eastern 
and the western slopes of this range, and the greater rivers, 
partly owing to its position partly to climatic conditions 
respecting rainfall, flow mainly from the western slopes. 
The immense Congo, with all its gigantic upper tributaries, 
rises wholly on the west, while even the Nile, with its main 
components, the Albert Nile, the Sobat and the Blue Nile, 
drains mainly from the western slopes. So also, even the 
Zambesi derives most of its water from the west of the 
range, although it eventually cuts through the chain to an 
opening in the Indian Ocean. 
As is the case in the region of most great mountain 
ranges, there are to be found in Central Africa besides 
the chains of lofty heights, long, deep hollows which run 
parallel with, and between the ridges of the range itself, 
and these great depressions, which are now occupied 
by the lakes and the rivers, are often rock valleys, 
like the valley of Geneva. They have not, however, 
been formed by ice, and are not to be viewed as wholly 
the products of denudation operating in the past, any more 
A Naturalist in Mid- Africa ( 1896). 
t To the Mountains of the Moon. 
