Observations on the Nature and Importance of Geology. 301 



Geology has shared the fate of all experimental sciences. 

 Its first steps, for the most part directed by necessity, consisted 

 of loose and superficial observations on those phenomena more 

 immediately presented to our attention. But, as it is a peculiar 

 prerogative of our nature to entertain a desire of tracing back 

 causes, and explaining operations, theories of the earth were 

 early indulged in ; and these, although often absurd, were not 

 without their use. Afterwards it was considered presumptuous, 

 from those fragments of the earth's crust which we had looked 

 upon rather than examined, to draw conclusions as to the forma- 

 tion of the earth, and to relate its history, as if we had been co- 

 eval with the events ; and that true geology must be a collec- 

 tion, arrangement, and comparison of facts, and its theories on- 

 ly general observations. This view being generally admitted, 

 geology may be said to have passed from the condition of child- 

 hood, and assumed its station among the sciences. 



These theories are essentially different from those of other 

 branches of physical science. When the natural philosopher 

 makes mention of two electric fluids, or of a luminous matter, 

 he is perfectly well aware that the causes of electrical or lumi- 

 nous phenomena might be different from what he imagines ; yet 

 these modes of expression are most convenient for producing unity 

 and connection among the facts that have come under his observa- 

 tion. Geological theories are, on the contrary, of a purely histori- 

 cal character. Whether granite be a production of fire or water, 

 is a matter of indifference in the explanation of its origin, if we 

 are incapable of producing it either in the one way or the other ; 

 but whoever tells us that the present crust of the earth was 

 once in a state of fusion, and that, upon cooling, it became a so- 

 lid mass, exhibits an event which, like the heroic exploit of 

 a Curtius or a Clcelia, should be received only upon the most 

 indisputable testimony. Geological theories are, therefore, more 

 exclusive than physical ; hence a reason why geologists have al- 

 ways been more at variance than natural philosophers. 



It is therefore the duty of the geologist to proceed cautious- 

 ly with his conclusions. In return for that he is sufficiently in- 

 demnified by the nature of his study, which bears in the most 

 distinguished manner the peculiar character of all physical 

 science. 



