HISTORY OF 



built of materials evidently thrown up by the mountain. The 

 inference from all this is very obvious ; that the matter thus ex- 

 ploded cannot belong to the mountain itself, otherwise it would 

 have been quickly consumed ; it cannot be derived from mode- 

 rate depths, since its amazing quantity evinces, that all the places 

 near the bottom must have long since been exhausted ; nor can 

 it have an extensive, and, if I may so call it, a superfacial spread, 

 for then the country round would be quickly undermined; it 

 must, therefore, be supplied from the deeper regions of the earth ; 

 those undiscovered tracts where the Deity performs his wonders 

 in solitude, satisfied with selt-approbation ! 



CHAP. X. 



or EARTHQUAKES. 



Having given the theory of volcanoes, we have in some mea- 

 sure given also that of earthquakes. They both seem to proceed 

 from the same cause, only with this difference, that the fury of 

 the volcano is spent in the eruption ; that of an earthquake 

 spreads wider, and acts more fatally by being confined. The 

 volcano only affrights a province ; earthquakes have laid whole 

 kingdoms in ruin. 



Philosophers ' have taken some pains to distinguish between 

 the various kinds of earthquakes, such as the tremulous, the pu '- 

 sative, the perpendicular, and the inclined ; but these are rather 

 the distinctions of art than of nature, mere accidental differences 

 arising from the situation of the country or of the cause. If, foi 

 instance, the confined fire acts directly under a province or 

 town, it will heave the earth perpendicularly ujjward, and pro- 

 duce a perpendicular earthquake. If it acts at a distance, it will 

 raise that tract obliquely, and thus the inhabitants will perceive 

 an inclined one. 



Nor does it seem to me that there is much greater reason for 

 Mr Buffon's distinction of earthquakes ; one kind of which he 



1 Aristotle, Agricola, BuB'on. 



