302 THEORY of the EARTH. 



fuppofitions, in order to come at certain conclufions which may 

 be compared with the prefent flate of things. 



IT is not necefiary that the prefent land fliould be worn 

 away and wafted, exactly in proportion as new land fhall ap- 

 pear ; or, converfely, that an equal proportion of new land 

 fhould always be produced as the old is made to difappear. It 

 is only required, that, at all times, there fliould be a juft pro- 

 portion of land and water upon the furface of the globe, for 

 the purpofe of a habitable world. 



NEITHER is it required in the actual fyftem of this earth, 

 that every part of the land fliould be diflblved in its ftructure, 

 and worn away by attrition, fo as to be floated in the fea. 

 Parts of the land may often fink in a body below the level of 

 the fea, and parts again may be reftored, without waiting for 

 the general circulation of land and water, which proceeds with 

 all the certainty of nature, but which advances with an imper- 

 ceptible progreflion. Many of fuch apparent irregularities may 

 appear, without the lead infringement on the general fyftem. 

 That fyftem is comprehended in the preparation of future land 

 at the bottom of the ocean, from thofe materials which the 

 diflolution and attrition of the prefent land may have provided, 

 and from thofe which the natural operations of the fea afford. 



IN thus accomplifhing a certain end, we are not to limit na- 

 ture with the uniformity of an equable progreflion, although 

 it be neceflary in our computations to proceed upon,equalities. 

 Thus alfo, in the ufe of means, we are not to prefcribe to na- 

 ture thofe alone which we think fuitable for the purpofe, in 

 our narrow view. It is our bufinefs to learn of nature (that 

 is by obfervation) the ways and means, which in her wifdom 

 are adopted ; and we are to imagine thefe only in 'order to find 

 means for further information, and to increafe our knowledge 

 from the examination of things which actually have been. It 

 is in this manner, that intention may be found in nature ; but 



this 



