300 The Vitriol 



quantity ; and the higher the pyrites rifes in this 

 metal, the lefs it vitriolifes ; this is owing to the 

 fulphur, which being here fet free from the metal- 

 earth, and yet again operating thereon in another 

 manner, is held very faft by the copper, to which 

 it adheres more clofely than to iron : then the ar- 

 fenic oppofes together with the copper, not only in 

 the copper-pyrites ) but alio in the iron-pyrites with- 

 out any copper •, inftances of the one fort are evi- 

 dent in every copper-pyjites-ore, of the other fort 

 in the Halfebrucke arfenical iron-pyrites. 



Laftly, the bufinefs alfo fometimes depends 

 purely on the texture, clofenefs, and grain, with- 

 out any copper and arfenic, though this is the 

 rareft cafe, as I learn from fome periwinkle and 

 mufcle pyrites , confiding purely of iron and 

 fulphur, yet without ever running to vitriol. Often 

 two caufes concur, as is ever the cafe in the yellow 

 pyrites^ where along with the copper, there cer- 

 tainly lodges arfenic : often, the bufinefs turns on 

 one caufe only, namely, the arfenic alone, or alfo 

 purely on the texture alone : often, all the three 

 concur, namely, in the fine-grained and fineft 

 fort of copper-ores : and, to conclude, we have 

 here a confirmation of the axiom, that one and the 

 fame effell may have very different caufes. 



This difference, both in the mixtion and tex- 

 ture of the pyrites^ manifefts itfelf often in one and 

 the fame vein \ where we have copper-ore and iron- 

 pyrites lying in each other interfperfedly ; and a- 

 gain, pyrites lying like fo many nuts or eggs in a 

 fhell, wherein upon breaking it fome fmall veins and 

 eyes of copper-pyrites appear. Among the AJme- 

 rode pyrites-balls^ commonly called iron-earth, and 

 for pure fulphur and iron the propereft and belt 



fort, 





