8 ABOUT VOLCANOS AND EARTHQUAKES. 



that there is a great cycle of changes going on, in which 

 the earthquake and volcano act a very conspicuous part, 

 and that pa] t a ixstorative and conservative one; in oppo- 

 sition to the steadily destructive and levelling action of 

 the ocean waters. 



(id.) How this can happen ; what can be the origin of 

 such an enormous power thus occasionally exerting 

 itself, will no doubt seem very marvellous Httle short, 

 indeed, of miraculous intervention but the mystery, 

 after all, is not quite so great as at first it seems. We 

 are permitted to look a little way into these great secrets 

 of nature ; not far enough, indeed, to clear up every 

 difficulty, but quite enough to penetrate us with admira- 

 tion of that wonderful system of counterbalances and 

 compensations ; that adjustment of causes and conse- 

 quences, by which, throughout all nature, evils are made 

 to work their own cure ; life to spring out of death ; and 

 renovation to tread in the steps and efface the vestiges 

 of decay. 



(ii.) The key to the whole affair is to be found in the 

 central heat of the earth. This is no scientific dream, 

 no theoretical notion, but a fact established by direct 

 evidence up to a certain point, and standing out from 

 plain facts as a matter of unavoidable conclusion, in a 

 hundred ways. 



(i2.) We all know that when we go into a cellar out of 

 a summer sun, it feels cool ; but when we go into it out 

 of a wintr}'' frost it is warm. The fact is, that a cellar, 

 or a well, or any pit of a moderate depth, has always, 

 day and night, summer and winter, the same degree of 



