( 384 ) 



Both thefe objedions, however, will, i^ 

 my opinion, be found to have little weight,- 

 "when we confider that this gas in burning 

 volcanos can never be pure, but muft ne- 

 ceflarily be mixed with fome mephitic gas,* 

 and, efpecially, v^ith carbonic acid gasy 

 which.; in volcanic countries, is rarely want- 

 ing. By this mixture the vivid brightnefs 

 which pure oxygenous gas would produce 

 in the ignited lava, will be greatly weakened^ 

 and the aftion of the fire be prevented from 

 being fo violent as to deftroy the charadters 

 of the primitive rock. 



This hypothefis, however, as I have faidj 

 I offer only for examination, and fhall be 

 very ready to rejedt it fliould it be found 

 defediive. The impofTibility of collecting 

 the fluid that efcapes with detonation from 

 this volcano, prevented me from afcer- 

 taining its nature accurately. I am, there- 

 fore, obliged to feek it by conjed:ure, hav- 

 ing recourfe to that elaftic fluid, the ex- 

 iftence of which in the volcano of Strom- 

 boli 1 believe certain, and which, in fome 



meafure. 



