( 374 ) 

 . While making thefe experiments, I wifh- 

 ed to fatisfy my curiofity relative to another 

 particular. Hitherto I had ufed frefh wa- 

 ter from a well : and 1 wiflied to afcertain 

 whether there was any difference in the 

 efFecls produced by water from the fea ; 

 fmce it appears highly probable that this 

 water, by entering among the iires of vol- 

 canos, is the caufe of their moft terrible 

 eructations. I, therefore, caufed fome to 

 be brought, in clofed vefTels, from the 

 neighbouring gulpli of Genoa ; but, when 

 I made ufe of it in fimilar experiments 

 on the fufed lavas, I found the refults per- 

 fectly the fame with thofe already defcribed. 



From this feries of experiments I think 

 we are authorifed to conclude, that when a 

 quantity of water falls on the burning 

 crater of a volcano, it has not the power of 

 producing explofions ; but that ^he latter 

 on the contrary are very violent when the 

 water, penetrating below, reaches the con- 

 flagration ; when fuddenly reduced to va- 

 pour by the heat, it finds no room for its 



dilatation ; 



