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eompofed in the fame manner as fom^ 

 tracts of that of No. I. Its bafe is argilla- 

 ceous, and it attaches to the tongue ; the fmall 

 cryltals of black mica and feltfpar which it 

 contains, are, however, uninjured. This lava, 

 iikewife, iffues in veins from the body af 

 that of No. II. 



Its produd in the furnace is a femi-tranf- 

 parent grey glafs, with the fullon of the 

 feltfpars. This lava has the peculiarity 

 of iirongly attacking the crucible ; com- 

 bining with the earth of which, it forms 

 round the fides an elegant, extremely trans- 

 parent glafs, refembling the emerald. 



V. Befides feveral beds of pitch-ftone 

 lava, which concur to the formation of 

 Catajo, there is one, near the fummit, 

 towards the fouth-weft, interfperfed with 

 innumerable very fine white flreaks parallel 

 to each other, and which form a ftrong 

 contrail to the red ftreaks of the pitch-ftone 

 lava. Thefe wdiite ftreaks, as far as I could 

 difcover, are the fame lava decompofed, 



J an^d 



