Prof. Kielhau on the Present State of Geology. 349 



celebrated fact, which shewed the possibility of the formation 

 of felspar " by heat," that fact, by means of whose discovery 

 volcanism was enabled to boast of its greatest triumph over its 

 old opponents, chemistry itself now places experiments, which 

 prove the possibility of producing felspar in the moist way.* 

 That notwithstanding this, chemists who are perfectly im- 

 partial with regard to geological disputes, when they have 

 only to choose between the Wernerian doctrine as to granite, 

 and that which prevails at present, would have no hesitation 

 in declaring for the latter, is apparent ; but that they will not 

 assert that the latter view is absolutely the right one, may well 

 be concluded from the advances which have lately been made. 



We may hope that these very advances in chemistry itself, 

 will contribute to shew, that the relation which must exist 

 between that science and geology, has hitherto not been pro- 

 perly understood. In investigations respecting these proble- 

 matical crystalline rocks, and other mineral masses of still 

 uncertain origin, chemistry can at most only afford geology 

 suggestions or considerations. It is for geology itself, with the 

 assistance of geognostical investigations, to examine, to what 

 extent the explanation proposed and the theories advanced, 

 are correct or not. But then it is chiefly requisite, in reference 

 to the phenomena existing in nature, to acquire that kind of 

 knowledge which is pure matter of fact ; for, should this know- 

 ledge of natural phenomena really become the touchstone of 

 theories, good care must be taken that the former is not by 

 anticipation modified by the latter. 



In another point of view also, it is of consequence, as re- 

 gards the true bearings of the facts, to elicit information which 

 no preconceived theory has influenced. This information is 

 not merely to be employed in testing suggestions made from 

 extraneous sources for the explanation of phenomena, but 

 also, as has already been repeatedly stated, to call forth avail- 

 able ideas, which hitherto could not have been obtained by 

 any other means. I hope to prove this by the following ob- 

 servations on some of the mineral masses, whose mode of 

 formation is involved in greater obscurity than that of any 

 others. I hope thus to shew the correctness of all the 



* Becquerel's Traite d» VElectricite, vol. v. p. 144, &c. 



