E 2 44 3 



CHAP. XIII. 



Of the original Particles, or of the 

 Principles of the Pyrites. 



E have hitherto treated of the mixed and 

 compounded parts of the pyrites > as (i.) its 

 iron-earth-, (2.) copper-earth ; (3.) crude, unme- 

 tallic earth, with which the two firft are ever en- 

 tangled 5 (4.) itsfulphur; (5.)* arfenic, and the 

 fandarach thence procurable ; (6.) the filver ; (7.) 

 the gold in the pyrites - y all thefe are to be found 

 in the pyrites, though not in equal regard or 

 consideration, fome being effential or conftituent 

 parts, others incidental only, and without which 

 the deilruclion of the whole either may, or may not 

 be effected. The proper ground- parts are an iron- 

 eafth, and fomething that is volatile, and that ei- 

 ther fulphur or arfenic •, all the others, namely, 

 the copper, gold, and filver, are incidental, as 

 the pyrites is often found to be without them •, but 

 as the proportion of the copperas often found to 

 exceed the iron-earth in weight, it is neceffary 

 to take a view of it in another light : yet, as 

 the copper rifcs and falls, nay, may be quite 

 Wanting, it might indeed be removed from the 

 clafs of incidental, and brought nearer to the 

 firft* order of parts ; but to diftinguifh it in 

 forne meafure from the parts, both of the firft 

 and fecond order, it may be affigned a mid 

 rank, and be called a iecondary conftituent part 



of thefflrjfef. 



1 



What 



