( 320 )' 



which renders probable the hypotbejis^ that 

 this elajiic vapour^ colleEled in a large 

 quantity^ and finding fome impenetrable 

 objlacle under the earthy may caiife earth- 

 quakes^ Jiibterraneous roarings y and burji 

 the fides of the mountains ^forcing the lava 

 to foiv out — Improbable^ hozvever^ that 

 this vapour is the caufe of the fery hail 

 ejeBed by volcanos — Neceffity of recurring 

 to other more poijoerful gafes to explain 

 thefe eruptions — 7^^ he prefence of thefe dif- 

 fer ettt gafes clearly indicated in fome vol" 

 canos— Probable, that in the greater and 

 more terrible ejeBions another agent much 

 more energetic concurs, that is, "water, 

 principally that of the fea, reduced to va- 

 pcur--^ConneBion between burning volca- 

 nos and the fea — l^he fudden retiring of 

 the latter,, in the vicinity ofVefuvius, at the 

 time of the mof terrible eruptions^ probably 

 occofioned by great quantities of its voaters 

 being abforbed in the caverns of the moun- 

 tain — E:-perimefits and accidents iiuhich' 

 prove the terrible nature of the explofions 

 and detonations of volcanos, in confequence 



of 



