ITALY. LETTER XI. 155 



corals, partly mixed or incruftated with a reddifh 

 iron-ochre, which is fimilar to the colcothar vitri- 

 oli. Under thefe circumfrances it is very fonorous; 

 which is owing to its longer expofition to an in* 

 tenle- lire *. 



2. Black compact lava, with white garnet-like 

 fherl-cryftallizations ; which are either vitreous, 

 tranfparent, or femi-pelkicid, or white opaque 

 milk-coloured. In the moft ancient .lavas, long 

 expofed to the air, they are friable and farina- 

 ceous. This lava is very common, and moft fre- 

 quent, not only near Vefuvius and Naples, but 

 likewife near the other Italian volcanos. 



3. Black compact lava, with round ftriated 

 fherl-columns, called ftangen-fpath; near Vefuvius 

 and Puzzuolo, on the fhore, at the right hand of 

 the road from Naples. 



4. Black compact lava, with white hexagonal 

 Iherl-prifms ; very fcarce. 



5. Black compact lava, with black (herl- fea- 

 thers or points, which are either thin and pin-like, 

 or fomewhat bigger, in a roundifli or hexagonal 

 form ; from Vefuvius. 



6. Black compact lava, with black flierl- flakes, 

 which feem to have been cracked by fire .from 

 fherl-prifms ; from Vefuvius. 



* Or rather to its form. 



7. Black 



