26 STABILITY OF FATUEE. 



ogy of a province, it is evident that our data must be insufficient 

 to warrant positive general conclusions. In discussing the clima- 

 tology of whole countries, or even of comparatively small local 

 divisions, we may safely say that none can tell what percentage 

 of the water they receive from the atmosphere is evaporated ; 

 what absorbed by the ground and conveyed off by subterranean 

 conduits ; what carried down to the sea by superficial channels ; 

 what drawn from the earth or the air by a given extent of forest, 

 of short pasture vegetation, or of tall meadow-grass ; what given 

 out again by surfaces so covered, or by bare ground of various 

 textures and composition, under different conditions of atmos- 

 pheric temperature, pressure and humidity; or what is the 

 amount of evaporation from water, ice or snow, under the vaiy- 

 ing exposures to which, in actual nature, they are constantly sub- 

 jected. If, then, we are so ignorant of all these climatic phe- 

 nomena in the best-known regions inhabited by man, it is evi- 

 dent that we can rely httle upon theoretical deductions applied 

 to the former more natural state of the same regions — less still to 

 such as are adopted with respect to distant, strange and primitive 

 countries. 



Stability of Nature. 



Nature, left undisturbed, so fashions her territory as to give it 

 almost unchanging permanence of form, outline and proportion, 

 except when shattered by geologic convulsions; and in these 

 comparatively rare cases of derangement, she sets herself at once 

 to repair the superficial damage, and to restore, as nearly as prac- 

 ticable, the former aspect of her dominion. In new countries, 

 the natural inclination of the ground, the self-formed slopes and 

 levels, are generally such as best secure the stability of the soil. 

 They have been graded and lowered or elevated by frost and 

 chemical forces and gravitation and the flow of water and vege- 

 table deposit and the action of the winds, until, by a general com- 

 pensation of conflicting forces, a condition of equilibrium has 

 been reached which, without the action of man, would remain 

 with little fluctuation for countless ages. 



We need not go far back to reach a period when, in all that 

 portion of the Korth American continent which has been occu- 

 pied by British colonization, the geographical elements very 



