C 47 ) 



fulphurlc acid with diiFerent earth?, the 

 lavas have become lighter and varioufly 

 coloured. 



As I vifited the Stoves three feveral times, 

 and examined wqth great attention the lavas 

 that had fuffered alteration by the adlion of 

 the fulphureous acid, I am enabled to add, to 

 the obfervations already given, fome others 

 which I believe to be new, and which I fhall 

 here briefly ftate. 



It was an obje61: equally important and 

 curious to afcertain to w^hat kinds of lavas 

 ftill remaining in the ilate in which they 

 were left by the fire, thofe belong which we 

 now fee decompofed by acids ; and as the 

 obfervations I had made at Solfatara di Poz- 

 zuolo and other places, had taught me that 

 the decompofition diminilhes, the deeper it 

 enters into the fubftance, I conceived that 

 the moft proper means to obtain this know- 

 ledge would be, to break fragments of the 

 lava, and examine the internal parts, to find 

 how far the decompofition had penetrated. 



The 



