Chap. LXX. THE PHENOMENON EXPLAINED. 
9 
Bamba,and especially in the district called Tin-sherifen 
which we shall visit on our return journey, is shut 
in and reduced to the width of a few hundred yards, 
so that the water, having expanded over such an 
immense tract and not exercising therefore the same 
pressure which such a volume of water would do 
under other circumstances if it were kept together 
in a narrower channel, preserves its level or even 
still increases in extent and depth, while the surplus 
produced by the fall of rain in the country higher 
up has already diminished. 
This is my mode of accounting for a phenomenon 
which seems to contradict in so great a measure the 
whole of the phenomena which have come under our 
observation with regard to the effects of rain and the 
rising of the rivers north and south of the equator, 
and imparts to the upper course of the Niger the 
same character as the Gabiin and other rivers of the 
equatorial line which reach their highest level in the 
course of February. 
Of course this state of the upper river, although 
it does not reach always the same level, cannot fail to 
exercise an influence also upon the lower part, where 
it is called Kwara, and where it has been visited re- 
peatedly by Englishmen. But although, on account of 
their being unaware of this character of the river, 
they have not paid much attention to its features at 
the beginning of the hot season, and have even 
rarely visited it at that period, nevertheless Mr. Laird, 
who spent several months in the Kwara, has not 
failed to observe a phenomenon which exactly cor- 
