348 Prof. Keilhau on the Present State of Geology. 



there is, therefore, no other method of determining which of 

 the various possible modes of formation was in such cases the 

 true one, except the investigation of the geognostical pheno- 

 mena, viz. of the forms of the masses, and of the whole cir- 

 cumstances of their occurrence. But this is just a work which 

 does not at all belong to the chemist as such. When we really 

 see chemists employed in answering the question I have men- 

 tioned, this takes place, inasmuch as they then make their 

 appearance in the character of geologists. That people should 

 be deceived in this matter is really very extraordinary. That, 

 for example, in the discussion on crystalline limestone, the 

 chemists have declared themselves in favour of the opinion 

 that this rock generally owes its formation to heat, has hardly 

 been caused by a single purely chemical consideration. Is it 

 at all more probable, for chemical reasons, that the calcareous 

 spar (which undoubtedly has in many instances been produced 

 without the action of heat), composing, with its small indivi- 

 dual crystalline portions, the granular limestone, should have 

 been formed in what is termed the dry way than in the moist ? 

 Certainly not. It is known, that in the last mentioned way 

 such a mass can even be produced artificially.* As already 

 remarked, it is not chemical reasons which have determined 

 that opinion, but it is speculations belonging entirely and alone 

 to the peculiar province of geology which have called it forth 

 from chemists. It is only a dilettantism in this interesting 

 science to which we owe this and similar judgments, before 

 which even geologists, according to the philosophical maxim 

 already quoted, bow with a loyalty that is even regarded by 

 them as a matter of no small pride. 



The volcanists should reflect well on the following ; that in 

 so far as chemists adhere at present, as they will perhaps do 

 for some time to come, to the hypothesis of the pyrogenic 

 origin of granite, the reason of this can be no other, than that 

 they have declared for this opinion in the character of amateurs 

 of geology ; for there assuredly exists no necessity arising out 

 of chemistry itself for adopting this view. By the side of the 



• The medallions which are made at San Filippo, in Tuscany, exhibit in their 

 interior a structure precisely similar to that of fine grained natural marble. 



