DESTRrCTTVENEeS OF MAN. 83 



Destructweness of Mem. 



Maji lias too long forgotten tliat tlie earth was given to him for 

 usufruct alone, not for consumption, still less for profligate waste. 

 Nature has provided against the absolute destruction of any of 

 her elementary matter, the raw material of her works ; the thun- 

 derbolt and the tornado, the most convulsive throes of even the vol- 

 cano and the earthquake, being only phenomena of decomposition 

 and recomposition. But she has left it within the power of 

 man irreparably to derange the combinations of inorganic matter 

 and of organic life, which through the night of aeons she had 

 been proportioning and balancing, to prepare the earth for his 

 habitation, when in the fulness of time his Creator should call 

 him forth to enter into its possession. 



Apart from the hostile influence of man, the organic and the 

 inorganic world are, as I have remarked, bound together by such 

 mutual relations and adaptations as secure, if not the absolute per- 

 manence and equihbrium of both, a long continuance of the 

 estabhshed conditions of each at any given time and place, or at 

 least, a very slow and gradual succession of changes in those con- 

 ditions. But man is everywhere a disturbing agent. Wherever 

 he plants his foot, the harmonies of nature are turned to discords. 

 The proportions and accommodations which insured the stabihty 

 of existing arrangements are overthrown. Indigenous vegetable 

 and animal species are extirpated, and supplanted by others of 

 foreign origin, spontaneous production is forbidden or restricted, 

 and the face of the earth is either laid bare or covered with a new 

 and reluctant growth of vegetable forms and with ahen tribes of 

 animal life. These intentional changes and substitutions constitute, 

 indeed, great revolutions ; but vast as is their magnitude and im- 



ance in determining the amount of erosion produced by running water, and, 

 of course, in measuring the consequences of clearing off the forests. The soil 

 of the French Alps yields very readily to the force of currents, and the decliv- 

 ities of the northern Apennines, as well as of many minor mountain ridges in 

 Tuscan)' and other parts of Italy, are covered with earth which becomes itself 

 almost a fluid when saturated with water. Hence the erosion of such sur- 

 faces is vastly greater than on many other mountains of equal steepness of 

 inclination. The traveller who passes over the route between Bologna and 

 Florence, and the Perugia and the Siena roads from the latter city to Rome, 

 will have many opportunities of observing such localities. 

 2* 



