THE BALANCE OF NATURE. 175 



intellectual being is affected by the character of the home 

 which Providence has appointed, and we have fashioned, for 

 our material habitation. 



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" We cannot always distinguish between the results of man's 

 action and the effects of purely geological or cosmical causes. 

 The destruction of the forests, the drainage of lakes and 

 marshes, and the operations of rural husbandry and industrial 

 art have unquestionably tended to produce great changes in 

 the hygrometric, thermometric, electric, and chemical condi- 

 tion of the atmosphere, though we are not yet able to measure 

 the force of the different elements of disturbance, or to say 

 how far they have been neutralized by each other, or by still 

 obscurer influences ; and it is equally certain that the myriad 

 forms of animal and vegetable life which covered the earth 

 when man first entered upon the theatre of a nature whose 

 harmonies he was destined to derange have been, through his 

 interference, greatly changed in numerical proportion, some- 

 times much modified in form and product, and sometimes 

 entirely extirpated. 



" The physical revolutions thus wrought by man have not, 

 indeed, all been destructive to human interests, and the 

 heaviest blows he has inflicted upon nature have not been 

 wholly without their compensations. Soils to which no nutri- 

 tious vegetable was indigenous ; countries which once brought 

 forth but the fewest products suited for the sustenance and 

 comfort of man while the severity of their climates created 

 and stimulated the greatest numbers and the most imperious 

 urgency of physical wants surfaces the most rugged and 

 intractable, and least blessed with natural facilities of com- 



