Notice of Active and Extinct Volcanos. 8& 



culated to serve in the economy of nature, I think it more consis- 

 tent with sound philosophy to limit myself, to those effects which 

 have obviously been produced by their action, and to those final 

 causes of their existence, which may be presumed from phenom- 

 ena which we ourselves witness. 



"The former of these inquiries has already been insisted up- 

 on, and the occurrence of basalts in every class of rocks, under 

 circumstances which establish igneous action, indicates that vol- 

 canos have existed almost from the commencement of our globe. 



" With respect to the latter point, I shall only remark, that 

 whatever may have been the end, for the sake of which the accu- 

 mulation of inflammable materials in the interior of our globe 

 was ordained, their existence there, under circumstances which 

 admitted of their undergoing from time to time inflammation, ren- 

 dered the production of volcanos not only a natural consequence, 

 but even an useful provision. 



" They are the chimneys, or rather the safety valves, by which 

 the elastic matters are permitted to discharge themselves, with* 

 out causing too great a strain upon the superficial strata. 



" Where they do not exist, they give place to a visitation of a 

 much more destructive nature ; for those who have experienced 

 a volcano and an earthquake will readily testify, that the conse- 

 quences of the former are by no (beyond ?) comparison lighter 

 than those of the latter. i 



"The same country is indeed often exposed to this double ca- 

 lamity, but that the existence of the volcano is even there a 

 source of good, appears from the fact, that the most terrible ef- 

 fects are felt at a certain distance from the orifice, although the 

 focus of the action is probably not far removed from the latter. 



" The agitations, which took place during six years at Lance- 

 rote, likewise shew, how much more destructive the effects of 

 subterranean fire appear to be, where no permanent vent is es- 

 tablished. 



"Thus far we have proceeded on solid grounds, — but if we are 

 willing to push the enquiry farther, and to speculate on the other 

 ends which volcanos may be intended to answer, it may perhaps 

 not be too bold an hypothesis, when we consider their general 

 distribution, to imagine that they are among the means which na- 

 ture employs, for increasing the extent of dry land in proportion 

 to that of the ocean. 



" That such is the tendency of the processes daily taking place, 

 appears from various considerations, and from none more re- 

 markably than from the formation of coral reefs, a cause of in- 

 crease to the quantity of dry land, with which the destroying 

 agencies that are also at work have nothing to compete. 



" In speaking of the Canary islands I observed, that volcanic 

 processes seem much more frequently to have elevated, than to 



