170 A SYSTEM OF 



SECT. CCXCVIII. 



D. Pearl flag, Scorite .conft antes glolulisvitreh 

 conglomeratis. 



Is compounded of white and greenifh 

 glafs particles, which feem to have been 

 conglutinated while yet foft, or in fufion. 

 Found on the Ifle of Afcenfion. 



SECT. CCXCIX. 



E. Slag-fand or afhes, Scoria pulverulent*. 

 Cineres Vulcanorum. 



This is thrown forth of the volcanos in 

 form of larger or fmaller grains. It may 

 perhaps be the principle of the Terra Puz- 

 zolana (Se£k. ccix. a.\ becaufe fuch an earth 

 is laid at this time to cover the ruins of 

 Herculaneum near Naples, which hiftory 

 informs us was deftroyed by a volcano 

 during an earthquake. 



SECT. CCC. 



Observations on the preceding Slags. 



It feems as if we could not go any farther in the 

 arrangement of bodies belonging to the mineral 

 kingdom, than to the black mould (Seel, cexciii.) 

 and the flags, as being the extremes. 



However, if thefe flags likewife decay, and in 

 length of time become an earth, which poliibly 

 may happen ; there is then a new fubftance be- 

 yond them, which however may return back and 

 circulate again in fotne known form. It is ob- 

 vious how the old heaps of flags from the iron 



ittrnaces 



