EFFECTS OF DESTEUCTION OF THE FOREST. 293 



over its surface, drift away the snow that sheltered it from the 

 frost, and dry up its scanty moisture. The precipitation becomea 

 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 seawards, 

 instead of filling a retentive bed of absorbent eai-th, and storing 

 up a supply of moisture 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 

 pidverized by sun and wind, and at last taken up by new combi- 

 nations. The face of the eai-th 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 quanti- 

 ties 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 rivulets, want- 

 ing their former regularity of supply and deprived of the protect- 

 ing 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 elevation of the beds of water- 

 courses and of lakes, by the deposition of the mineral and vegeta- 

 ble 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 danger- 

 ous sand-bars. 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 to- 

 gether, a new carpeting 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 ster- 

 ile rock, and the rich organic mould which covered them, now 

 swept down into the dank low grounds, promotes a luxuriance of 

 aquatic vegetation that breeds fever, and more insidious forms of 

 mortal disease, by its decay, and thus the earth is rendered no 

 longer fit for the habitation of man.* 



* Almost every narrative of travel in those countries which were the earliest 

 s©«\t'» of ci'»ili?ation, contains evidence of the truth of these general statements^ 



