{ 376 ) 



of the liquid lava within the crater, by 

 which it rofe to a certain height, inflating 

 with multiplied tumors, which burft at the 

 moment the detonation and ejedion took 

 place ; that this was immediately followed 

 by a finking of the lava to a certain depth, 

 to which fucceeded a new riimg of the 

 fame, with like inflations and tumors that 

 burft v^'ii.h iimilar ejed:ions and explofion ; 

 and that in this alternation coiififted the 

 aiftion of that volcano* 



I have already fuppofed that thefe tumors 

 are cauf-d by an elaftic fluid imprifoned 

 within them, which endeavours to obtain a 

 pafTage, and at length finds one, by burfting 

 the tumors and forcing up their fragments 

 to a confiderable height ; and this con- 

 jecture I then thought extremely well- 

 founded, and am ftill of the fame opinion. 

 It Oily remaiiied to enquire what might be 

 the nature of this fluid ; which enquiry I 

 referved to be made in the prefent chapter, 

 in which I treat of the nature of the gafes 

 of volcanos. From the obfervations I made 



on 



