EFFECTS OF DESTRUCTION OF THE FOREST. .215 
summer, and seared by the rigors of winter. Bleak winds 
sweep unresisted over its surface, drift away the snow that 
sheltered it from the frost, and dry up its scanty moisture. 
The precipitation becomes as irregular as the temperature; the 
melting snows and vernal rains, no longer absorbed by a loose 
and bibulous vegetable mould, rush over the frozen surface, 
and pour down the valleys seaward, instead of filling a reten¬ 
tive bed of absorbent earth, and storing up a supply of moist¬ 
ure to feed perennial springs. The soil is bared of its covering 
of leaves, broken and loosened by the plough, deprived of the 
fibrous rootlets which held it together, dried and pulverized 
by sun and wind, and at last exhausted by new combinations. 
The face of the earth is no longer a sponge, but a dust heap, 
and the floods which the waters of the sky pour over it hurry 
swiftly along its slopes, carrying in suspension vast quantities 
of earthy particles which increase the abrading power and 
mechanical force of the current, and, augmented by the sand 
and gravel of falling banks, fill the beds of the streams, divert 
them into new channels and obstruct their outlets. The rivu¬ 
lets, wanting their former regularity of supply and deprived of 
the protecting shade of the woods, are heated, evaporated, and 
thus reduced in their summer currents, but swollen to raging 
torrents in autumn and in spring. From these causes, there is 
a constant degradation of the uplands, and a consequent eleva¬ 
tion of the beds of watercourses and of lakes by the deposi¬ 
tion of the mineral and vegetable matter carried down by the 
waters. The channels of great rivers become unnavigable, 
their estuaries are choked up, and harbors which once sheltered 
large navies are shoaled by dangerous sandbars. The earth, 
stripped of its vegetable glebe, grows less and less productive, 
and, consequently, less able to protect itself by weaving a new 
network of roots to bind its particles together, a new carpet¬ 
ing of turf to shield it from wind and sun and scouring rain. 
Gradually it becomes altogether barren. The washing of the 
soil from the mountains leaves bare ridges of sterile rock, and 
the rich organic mould which covered them, now swept down 
into the dank low grounds, promotes a luxuriance of aquatic 
