BY COiJPRESSIO:?. <2Q^ 



Sect. ix. — Application of the foregoing results to Geology, — ■ 

 The fire employed in the Huttonian Theory is u modification 

 of that of the Volcanoes. — This modifcation must take place 

 in a lava previous to its eruption. — An Internal Lava is CU' 

 pable ofjnelting Limestone. — The effects of Volcafiic Fire on 

 substances in a subterranean and siib?narine situation^ are the 

 same as those ascribed to Fire in the Huttonian Theory. — 

 Our Strata were once in a similar situation^ and then under- 

 icvent the action off re. — All the conditions of the Hnftonian 

 Theory beitig thus combined, the formation of all Rocks may 

 be accounted for in a satisfactory manner. — Conclusion. 

 Having investigated, by means of the foregoing experiments, The results ap-- 

 some of the chemical suppositions involved in the Huttonian ^ ''^ ogeoo- 

 Theory, and having endeavoured to assign a determinate limit 

 to the power of the agents employed ; I shall now apply these 

 results to Geology, and inquire how far the events supposed 

 anciently to have taken place, accord with the existing state 

 of our globe. 



The most powerful and essential agent of the Huttonian Fire is the es- 

 Theory, is Fire, which I have always looked upon as the same sentiai agent of 

 I /. , ,•/- 1 . • 1- I thv- HuttoBiaii 



With that of volcanoes, modified by circumstances which must, theory. 



to a certain degree, take place in every lava previous to its 



eruption. 



The original source of internal fire is involved in great ob- To account fos 



scuritv ; and no sufficient reason occurs to me for deciding ^''^ °!;'^*? ^^ 

 ■^ ' . '^ that fire is no 



whether it proceeds by emanation from some vast central re- part of the doc- 



^ervoir, or is generated by the local operation of some chemi- *'^'"^." , ^}^^ 



cal process. Nor is there any necessity for such a decision : as a mere fact. 



all we need to know is, that internal fire exists, which no one 



can doubt, who believes in the eruptions of Mount Vesuvius. 



To require that a man should account for the generation of 



internal fire, before he is allowed to employ it in geology, is no 



less absurd than it would be to prevent him from reasoning 



about the construction of a telescope, till he could explain the 



nature of the sun, or account for the generation of light.* 



* This topic, however, has of late been much urged against us, 

 and an unfair advantage has been taken of what Mr. Playfair lias 

 said upon it. What he gave as mere conjecture on a subject of 

 collateral importance, has been argued upon as the basis and 

 fundamental doctrine of the system. 



D 2 d But 



