( 3^^ ) 



Modern volcanifts have fuppofed that thefe 

 are various gafes, which, endeavouring to 

 obtain a palfage through the liquid fub- 

 flances In which they are enveloped, force 

 them impetuoully out of the crater, and 

 fometimes to an enormous height. The 

 prefence of thefe gafes is certainly not ob- 

 fcurely manifefted by the hiffing founds 

 that are heard during the raging of volca- 

 nos, as has been obf^rved of Vefuvius, 

 which, from its vicinity to Naples, is the 

 volcano that has been mofl: attentively exa- 

 mined. Simikir hifling founds I likewife 

 obferved at Stromboii, of the eruptions of 

 Vv^hijh volcano I Ihall prefently have occa- 

 fion again to fpeak. 



But what is the nrture of thefe different 

 gaifes ? It is evident that to afcertain this it 

 would be neceiTary to colled: them in the 

 volcanic effervefcences for a chemical exa- 

 mination, which is perhaps impoffible, from 

 the manifeft danger there would be of fall- 

 ing a viftim to fo imprudent a curiofity. 

 We can therefore obtain no knowledge df 



them 



