154 TRAVELS THROUGH 



i. Black lava, ferruginous, entirely limilar to 

 black icon-flags or fcorios, is the mod common 

 of all, covering' Vefuvius on every fide, except 

 towards th'e-fea, where it lies deeply buried under 

 black funds and afhes. A white lichen, which I 

 flever fa\v ftourifhing, is frequently growing upon 

 it. Its eruptions are attended with ftrong ebulli- 

 tion and ffcimming, which occafions the large air- 

 bladders or hollow caverns mentioned before. For 

 the fame reafon its furface is commonly very rough 

 and unequal, xvhich makes the walking upon it 

 extremely difficult. Now and then it flowed in 

 waves,- (till appearing after its cooling. It is porous 

 in the furface, fpungy, and light, and therefore em- 

 ployed in vaulted roofs. At a greater depth it is ex- 

 tremely compafr, and th'e'n employed in foundations 

 and pavirrgs of the ftreets. Such lava is at prefent 

 chiefly dug out at the right hand of the road from 

 Naples to Puzzuvlo, from a lava-torrent of the 

 Solfatara volcano ; it is dug likewife between Por- 

 tia and Pompeja, from that large and terrible lava 

 torrent, which in one of the lateft eruptions run 

 down Vefuvius acrofs the road into the fea. They 

 here cut the lava into fquare pieces, or into paral- 

 klopi-pedes, and {hip it thence to Naples, even as 

 far as Salerno^ and other diilant places. This 

 black flaggilh lava appears in the inner fide of 

 the funnel in the form of grapes or branch-like 



corals, 



