( 22 ) ~ 



the few plants which feebly vegetated on 

 the declivities of the mountain. 



It has been already faid, that the rapid 

 defcent of the rain-v/aters on that part of 

 the mountain which leads to the ftoves, 

 has corroded the tufa to a great depth ; 

 and it is in the middle of thefe corrofions 

 that we meet with various volcanic bodies, 

 which, together with others lying in the 

 public road, merit well to be defcribed. 



Firft, we find pieces of enamel of every 

 fize, which, though they are fmooth with- 

 out, when broken, have, within, an angular 

 fradure. Their colour is a pale blue, they 

 have no great brilliancy, nor are they very 

 hard, as they fly in pieces when flruck 

 againft the fteel. The caufe of the want 

 of hardnefs in this enamel, may be afcribed 

 to the filTures, of which it is full ; and 

 thefe, perhaps, are to be attributed to the 

 pieces of enamel being red-hot when they 

 fell into the tufa not yet dry. The felt- 

 fpars it contains have the fame cracks, and 



probably from the fame caufe. 



In 



