6 
TRAVELS IN AFRICA. 
Chap. LXX. 
man acquainted witli the subject. For when he knows 
that the rising of these rivers is due to the fall of the 
tropical rains, he will naturally expect that the Niger, 
like its eastern branch, the Tsadda or Benuwe, or 
the Nile, should reach its highest level in August or 
September. The fact can only be partly explained 
with the means at our disposal, and in the present 
state of our knowledge of this part of Africa, al- 
though it is illustrated by similar cases, if we com- 
pare it with the anomalous rising of some South- 
African rivers ; especially the grand discovery of Dr. 
Livingstone, the Liambezi, which, forming in its 
upper course an immense shallow sheet of water, col- 
lects here the greatest amount of water at a time 
(July and August) when its lower course, the Zam- 
bezi, separated from it and withdrawn from the im- 
mediate effects of the waters collected above by the 
marvellous narrowing of the river-bed from the Falls 
of Victoria* downwards, is in its lowest state, and, 
through the influence of the water by which it is 
joined in its lower course, reaches here its highest 
level at quite a different season, February and March. 
We have before us exactly the same phenomenon 
in the case of the Niger, the great W est- African river, 
* I assume here the identity of these two rivers, which, however, 
has not yet been fully demonstrated. Compare also the anomalous 
rising of the Chobe (Journ. Royal Geol. Soc., vol. xxii. p. 169.); al- 
though an isolated phenomenon, caused by an unusual and unequal 
fall of rain in the basin of the various branches of a great river- 
system, must not be confounded with a constant and regular 
course. 
