368 MacCulloch's System of Geology- 



the volcanic and trap rocks, and pronounce their natural-his- 

 torical character identical ; but how infinitely more general and 

 conclusive the deductions of the geologist, exercised by habits 

 of physical research, in pointing out the real discrepancies of 

 aqueous and igneous solution, the chemical effects of heat on 

 rocks, the proofs of mechanical force in elevation, the testimony 

 which the now rigid mass can be made to reveal of the direc- 

 tion and intensity of the effort. 



Need we touch on the loftier speculations connected with 

 geology : — Of the speculations which the figure of the earth 

 renders more sure than almost any others to be found in the 

 science, which yet, from the want of the requisite knowledge, 

 few geologists can do any thing but take upon trust : — Need we 

 allude to Mr HerscheFs inquiries into that portion of geologi- 

 cal dynamics connected with astronomy, — thus providing a 

 link between the revolutions of our globe, and those of the sys- 

 tem of which it forms but a single member? When we consi- 

 der the necessary difference, we had almost said opposition, 

 which subsists between the pursuits of natural history and those 

 of experimental philosophy, can we wonder at the want of tact 

 in observing, (or rather in treating observations,) the illogical 

 reasoning, the inadequacy of causes to effects, the arguments 

 a priori, the bigotry to hypotheses, which so frequently cha- 

 racterize the writings of mere descriptive geologists ; and we 

 must consider that the science rests on a tottering basis till 

 some one sufficiently qualified devotes himself to the physics 

 of the question, and places it on a better footing. But the 

 rage for technicalities, which gives the present geological school 

 its peculiar character, which at little expence of thought occu- 

 pies the physical and mental energies to a certain extent, and 

 permits the imagination to run wild in its most fantastic course, 

 whilst an error in nomenclature is the gravest offence it recog- 

 nizes, — so long as this rage continues in its full extent to di- 

 vert the mind from the whole to part, and to make natural 

 history the first, second, and third, requisite to geology, we 

 can hardly hope that those who might work a revolution in 

 the science, will be induced to set their face against the " ex- 

 clusive" habits of the age. But we believe a day must come 

 before geology is altogether worthy of the name of a science, 

 when men, (either in this or some other country,) worthy of 



