224 
INFLUENCE OF THE FOREST ON INUNDATIONS. 
various industrial processes of civilized life, the attention of 
French foresters and public economists has been specially 
drawn to three points, namely, the influence of the forests on 
the permanence and regular flow of springs or natural foun¬ 
tains ; on inundations by the overflow of rivers; and on the 
abrasion of soil and the transportation of earth, gravel, pebbles, 
and even of considerable masses of rock, from higher to lower 
levels, by torrents. There are, however, connected with this 
general subject, several other topics of minor or strictly local 
interest, or of more uncertain character, which I shall have 
occasion more fully to speak of hereafter. 
The first of these three principal subjects—the influence 
of the woods on springs and other living waters—has been 
already considered; and if the facts stated in that discussion 
are well established, and the conclusions I have drawn from 
them are logically sound, it would seem to follow, as a neces¬ 
sary corollary, that the action of the forest is as important in 
diminishing the frequency and violence of river floods, as in 
securing the permanence and equability of natural fountains; 
for any cause which promotes the absorption and accumula^ 
tion of the water of precipitation by the superficial strata of 
the soil, to be slowly given out by infiltration and percolation, 
must, by preventing the rapid flow of surface water into the 
natural channels of drainage, tend to check the sudden rise of 
rivers, and, consequently, the overflow of their banks, which 
constitutes what is called inundation. The mechanical re¬ 
sistance, too, offered by the trunks of trees and of undergrowth 
to the flow of water over the surface, tends sensiblv to retard 
* •) 
the rapidity of its descent down declivities, and to divert and 
divide streams which may have already accumulated from 
smaller threads of water.* 
* In a letter addressed to the Minister of Public Works, after the 
terrible inundations of 1857, the Emperor thus happily expressed him¬ 
self: “Before we seek the remedy for an evil, we inquire into its cause. 
Whence come the sudden floods of our rivers ? From the water which 
falls on the mountains, not from that which falls on the plains. The 
waters which fall on our fields produce but few rivulets, but those which 
