90 M. Keilhau's Theory of Granite, and other Rocks. 



that with us he must stand on the same ground as the vul- 

 canists, inasmuch as he takes for granted the strata-disturb- 

 ing influence of the granite. We must, therefore, endeavour 

 to find for ourselves a position from which we may discover the 

 causal connection, if not of all, at least of a greater number of 

 the facts we have stated, than it is possible to do by the 

 hitherto existing theories, — I allude chiefly to Neptunism and 

 Vulcanism as the only ones which ha^ve as yet received any 

 full exposition, and whose principles have been clearly set down. 

 Before we go into the subject itself, it becomes necessary to 

 obtain a clear view of our position, and to consider especially 

 our relation to chemistry. With this science geologists are 

 most intimately connected; and in a particular manner, the 

 theory of granite and the other crystalline mountain-rocks, 

 stands very closely allied to it. That the truths of geology 

 and chemistry can never be found in contradiction to each 

 other, lies in the nature of things. But both sciences have the 

 same rank : we must not, as would almost seem to be required, 

 ascribe such a supremacy to chemistry, that the geologist 

 should not be able to step beyond the point of development 

 corresponding to the stage in its progress at which chemistry 

 may have arrived. The contingency may readily be imagined, 

 of a subject being extremely problematical in chemistry, with 

 regard to which we may be able to form a decided opinion by 

 the aid of geognostical facts; and that, ^vhile a geologist directs 

 his attention to what has taken place, or is now going on, in the 

 great laboratory of nature, he may thus discover phenomena, 

 and unfold ideas connected with the province of chemistry, 

 which he could not reach in the workshops of art. It would, 

 therefore, be quite in the order of things, that the geologist, by 

 his theories with respect to granite and the other massive rocks, 

 should advance before the experimental chemist ; and even if 

 it should chance to the latter to produce a granite perfectly 

 similar to that which is formed by nature, the geologist is not 

 absolutely bound to admit as the process of formation of the 

 natural rock, that which took place with regard to the artificial 

 product, when he finds that mode of formation at variance with 

 geognostical phenomena. The mode of theorizing with respect 

 to granite, &c. has been this, — that an hypothesis founded on 



