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24 



ILLUSTRATIONS OF THE 



Die gas, and its affinity to calcareous earth, I am 

 not fare but that'Dr Hutton's theory was, at 

 leaft, partly formed, though it mud certainly 

 have remained, even in his own opinion, expo- 



His adiive and penetra 



th 



per 



fed to great difficulties. 



ting genius foon perceived 



of his friend, the folution 



and formed that happy combination of p 



f thofe diffi 



pies, which has enabled 



plain the moll 



time 



enigmatical appearances in the natural hiftory of 



the earth. 



As we are not yet far removed from the 



when our chemical knowledge was too imperfed 

 to admit of a fatisfadory explanation of the phe- 

 nomena of mineralogy, fo it is not unlikely 



we are 



pproaching to oth 



difc 



th 



It 



are to throw new light on this fcience. 



w. 



would, however, be to argue flrangely to fay 



that we muil wait 



1 thofe difc 



are 



made before we begin any theoretical reafon 

 ings- It this rule were follov/ed, we lliould 



If this rule 

 not know where the 

 lay, nor when the 



mperfeclions of our fc 



med 



were 



found 



ihould we be in a condition to avail ourfelves of 

 them.. Such conduct would not be caution, but 

 timidity, and an excefs of prudence fatal to all 

 philofophical inquiry. 



457. The truth, indeed, is, that in phyfical in- 

 quiries, the v/ork of theory and obfervation muft 



4 



r 



t 



f( 



f 



1 



