190 
ARE SOILS ENRICHED, IMPOVERISHED, [Part III. 
run of rain, or the thawing of mountain snow; 
and the size of the channels of all torrents and 
rivers (except in alluvial parts, for a reason 
which will be given) is in proportion to the 
heavy floods of rain which occasionally rush 
through them, not to the comparatively small 
volume of spring water which always flows 
down them. 
Lyell, quoting Mr. Everest, calculates that in 
the rainy season (four months) the Ganges dis¬ 
charges into the sea a weight of earth equal to 
fifty-six great Pyramids ; and in the other eight 
months only the weight of four Pyramids. Now, 
if Professor Sedgwick will only grant us these 
four Pyramids for the snows of the Himalaya, 
we shall have an annual superficial wash of soil 
amounting in weight to sixty Pyramids. This 
is the ordinary and annual work resulting from 
the operation of ordinary and annual rains on 
one river basin. But how many extraordinary 
floods, the result of extraordinary rains, have 
passed over the Ganges ! 
Does Professor Sedgwick think that all this 
soil comes every year from the erosion of the 
banks of the Ganges, or even from the valley 
of the Ganges ? If it did, the valley of the 
Ganges would soon be barer of soil than its de- 
