90 HISTORY or 



tually often burst with the great violence of the 

 flame; that air may be supposed at depths at 

 least as far as the perpendicular fissures descend. 

 But the best answer is a well known fact ; name- 

 ly, that the quantity of matter discharged from 

 JEtna alone, is supposed, upon a moderate com- 

 putation, to exceed twenty times the original 

 bulk of the mountain.* The greatest part of 

 Sicily seems covered with its eruptions. The 

 inhabitants of Catanea have found, at the dis- 

 tance of several miles, streets and houses sixty 

 feet deep, overwhelmed by the lava or matter it 

 has discharged. But what is still more remark- 

 able, the walls of these very houses have been 

 built of materials evidently thrown up by the 

 mountain. The inference from all this is very 

 obvious ; that the matter thus exploded cannot 

 belong to the mountain itself, otherwise it would 

 have been quickly consumed ; it cannot be de- 

 rived from moderate depths, since its amazing 

 quantity evinces, that all the places near the bot- 

 tom must have long since been exhausted ; nor 

 can it have an extensive, and, if I may so call it, 

 a superficial spread, for then the country round 

 would be quickly undermined : it must, there- 

 fore, be supplied from the deeper regions of the 

 earth ; those undiscovered tracts where the Deity 

 performs his wonders in solitude, satisfied with 

 self-approbation ! 



* Kirchcr, Mund. SubU vol. i. p. 202. 



