THEORY of the EARTH. 215 



THE heights of our land are thus levelled with the fhores ; 

 our fertile plains are formed from the ruins of the moun- 

 tains ', and thofe travelling materials are flill purfued by the 

 moving water, and propelled along the inclined furface of the 

 earth. Thefe moveable materials, delivered into the fea, can- 

 not, for a long continuance, reft upon the more ; for, by the 

 agitation of the winds, the tides and currents, every moveable 

 thing is carried farther and farther along the {helving bottom 

 of the fea, towards the unfathomable regions of the ocean. 



IF the vegetable foil is thus conftantly removed from the fur- 

 face of the land, and if its place is thus to be fupplied from 

 the diflblution of the folid earth, as here reprefented, we may 

 perceive an end to this beautiful machine ; an end, arifing from 

 no error in its conflitution as a world, but from that deftrucli- 

 bility of its land which is fo neceffary in the fyftem of the 

 globe, in the ceconomy of life and vegetation. 



THE immenfe time necefTarily required for this total deftruc- 

 tion of the land, muft not be oppofed to that view of future 

 events, which is indicated by the fiireft facls and moft approved 

 principles. Time, which meafures every thing in our idea, 

 and is often deficient to our fchemes, is to nature endlefs and 

 as nothing ; it cannot limit that by which alone it had exiflence ; 

 and as the natural courfe of time, which to us feems infinite, 

 cannot be bounded by any operation that may have an end, the 

 progrefs of things upon this globe, that is, the courfe of na- 

 ture, cannot be limited by time, which muft proceed in a con- 

 tinual fucceffion. We- are, therefore, to confider as inevitable 

 the deftruclion of our land, fo far as effected by thofe opera- 

 tions which are neceflary in the purpofe of the globe, confider- 

 ed as a habitable world , and fo. far as we have not examined- 

 any other part of the ceconomy of nature, in which other ope- 

 rations and a different intention might appear. 



WE have now confidered the globe of this earth as a machine, 

 coiiftruaed upon chemical as well as mechanical principles, 



by 



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