from the PrRiTEs.' 305 



lifaiion, though in vain, I found them of fuch clofe 

 texture, as to render them unfit for it, either ex- 

 ternally or internally. 



Laftly, I have had inftances, where the bodies, 

 were thoroughly rufted, yet neither burft, nor 

 fallen to pieces ; but then many fuch fhells are not 

 pure pyrites, but greatly mixed with other earth, 

 and alio ftone, particularly, ihivery, loamy, and 

 fpathy matters •, nay, fome contain no pyrites, 

 but fuch earths only •, and, in that cafe, neither an 

 expanfive force, nor a vitriolifation, but only a lei— 

 furtiy rutting, and reduction to earth, are to be 

 expected. 



Thus much of frefh pyrites ; but that the air alfo 

 works on the defulphurated and thoroughly burnt 

 pyrites towards vitriolifation, we fhall hereafter men- 

 tion, having firit to treat of the other inftrument, 

 namely, fire. And here we muft premife fome- 

 thing on the internal caufality, or how the fponta- 

 neous vitriolifaiion of pyrites happens internally. 



Phiiofophers might readily call it magnetifm, to 

 denote a mutual action of damps and juices; on 

 the fide of the patient, namely, the pyrites, con- 

 fining in a receptivity, and on the fide of the agent, 

 or air, in an influx. Miners exprefs it by the term 

 weathering, and very properly, as they ufually call 

 air, weather ; befides, affirming, that we are by it to 

 understand, not a deft ruction of the matters of the 

 pyrites, but only of its texture or cohefion •, lead of 

 all are we to imagine it a reduction to its original 

 parts, or a feparation, but a new production. The 

 refolution here produced is indeed fo far a fepara- 

 tion into parts, as the fulphur is abfolutely to be fet 

 free from its metal earth, but in that very act the 



X new 



