INFLUENCE OF THE FOREST ON SPRINGS. 
201 
ally received opinion. * * * But while the facts I have 
stated have been established, it has been observed, at the same 
time, that, since the clearing of the mountains, the rivers and 
the torrents, which seemed to have lost a part of their water, 
sometimes suddenly swell, and that, occasionally, to a degree 
which causes great disasters. Besides, after violent storms, 
springs which had become almost exhausted have been ob¬ 
served to burst out with impetuosity, and soon after to dry up 
again. These latter observations, it will be easily conceived, 
warn us not to admit hastily the common opinion that the 
felling of the woods lessens the quantity of rain ; for not only 
is it very possible that the quantity of rain has not changed, 
but the mean volume of running water may have remained 
the same, in spite of the appearance of drought presented by 
the rivers and springs, at certain periods of the year. Perhaps 
the only difference would be that the flow of the same quantity 
of water becomes more irregular in consequence of clearing. 
For instance : if the low water of the Phone during one part 
of the year were exactly compensated by a sufficient number 
of floods, it would follow that this river would convey to the 
Mediterranean the same volume of water which it carried to 
that sea in ancient times, before the period when the countries 
near its source were stripped of their woods, and when, prob¬ 
ably, its mean depth was not subject to so great variations as 
in our days. If this were so, the forests would have this value 
—that of regulating, of economizing in a certain sort, the 
drainage of the rain water. 
“ If running streams really become rarer in proportion as 
clearing is extended, it follows either that the rain is less abun¬ 
dant, or that evaporation is greatly favored by a surface which 
is no longer protected by trees against the rays of the sun and 
the wind. These two causes, acting in the same direction, 
must often be cumulative in their effects, and before we at¬ 
tempt to fix the value of each, it is proper to inquire whether 
it is an established fact that running waters diminish on the 
surface of a country in which extensive clearing is going on ; 
in a word, to examine whether an apparent fact has not been 
