In the Pyrites.' 113 



is the moft univerfal metal in nature, there being 

 fcarce a vein, whether of lead, tin, or even of the 

 richer forts, without it ; though there are veins of 

 pure copper-ore, without any admixture. (3.} 

 Along with the fulphur in the pyrites, copper exhi- 

 bits much fuch a mixture as iron does, only that 

 in one the colour is fomewhat more yellowim, in 

 the other more pale : and in this refemblance other 

 ores do not equal the pyrites, though they may one 

 another : for inflance ; fulphur with lead, fulphur 

 with regulus, alfo, by means of art, fulphur with 

 tin, have a confiderable refemblance among them- 

 felves. (4.) Copper, 'tis true, does not emit its 

 fulphur fo readily from its ore as iron does, but: 

 rather runs, and cakes together; and therefore 

 will not bear any violence of fire, but only mould 

 be treated with a foft degree of roafling: and 

 when, by the interpofition of quartzy, mock- 

 leady, and the like ilubborn forts of earth, their 

 running together, or caking, is prevented, ths 

 fulphur alfo the more readily feparates. (5.) Both 

 of them, in one and the fame manner, receive 

 again the fulphur by cementation ; only that the 

 copper is fomewhat more penetrated by it, alfo re- 

 tains more of it, and for a longer time. For the 

 reft, both of them, along with fulphur, form a 

 rufly, footy mafs -, whereas the white metals, and 

 the femi-metals, ufually, by its means, acquire a 

 glittery, antimonial, and thus a more ory form. 

 (6.) All 'imperfect metals, without any one addi- 

 tion, may be made to burn away, or rather lofe 

 their metalleity, and turn to an earth •, yet none 

 fo eafily as iron and copper. Stahl * fuppofes this 

 to happen fooner to the latter than to the former, 

 but, in my opinion, equally to both ; though, 

 from my proofs, which are difficult to be male 



I accu- 



* Specim. Bech. p. 298. 



