( 324 ) 

 mena in the furnace. But, in the prefent 

 age, in which naturalifts and chemifts are 

 fo earneftly employed in analytical re- 

 fearches relative to the nature of aeriform 

 fluids, it is not fuffieient to affert and prove 

 the prefence of gafes in liquefied volcanic 

 products ; it is likewife incumbent on us to 

 endeavour to difcover their peculiar nature, 

 and thus prepare the means to afcertain 

 what part they may take in the eruptions 

 of volcanos. 



A fecond intereftlng objcd pointed out 

 in the Introduction, and which well merits 

 difcuffion, is the enquiry relative to the 

 adivity of volcanic fires. It is true, that 

 from a number of experiments which I 

 made in the furnace, both on volcanic pro- 

 ductions, and on the primitive rocks, almoft 

 all of which I fubjeCted to fufion, it appears 

 to be proved that this activity may not be 

 very great ; as a not very ftrong common 

 fire is fufficient to produce the fame effeCts. 

 From thefe experiments we certainly ac- 

 quire fome knowledge of which we were 



not 



