128 Of the unmetallic Earth 



could fcarce diftinguifh it. I muft here alfo ob- 

 viate a falfe notion, which, notwithstanding the 

 above hints, fome might be induced to form to 

 themielves of what we call pyrites-kidneys, and 

 balls ; wherein, upon breaking them in pieces, we 

 often obferve all manner of fandy, ftoney, and 

 often fcarce diftinguifhable particles, falfely confi- 

 dered as efTential parts in the mixtion of the pyrites. 

 I have lately had one fuch kidney, above a 

 pound in weight, from the falt-pit at Bochnia in 

 Poland, where neither externally, nor for an inch 

 deep within it, was to be found the lead trace of 

 of a rocky, or other admixed matter, as an efTen- 

 tial, conftituent part of the pyrites -, but, quite in- 

 ternally, I unexpectedly obferved fuch ; of which 

 the pyrity periwinkle and mufcle famples are plain, 

 palpable inftances. But, by the unmetallic, fixed 

 pyrites-earth, we are rather to undcrftand fuch 

 pyrites-particles, as are intimately introduced into 

 the pyrites-mixtion ; namely, an earth, both by the 

 volatile and fixed earth of the pyrites, fo fwallowed 

 up, minerallifed, and incorporated, as to be as 

 little diftinguifhable as the other pyrites-particles, 

 the fulphur, arfenic, iron, or copper, either by 

 the naked, or armed eye. 



This unmetallic earth, like the other principles 

 of the pyrites, is derived, as was fhewn above, 

 from the generation and production of the pyrites ; 

 from ore and ftone-forming juices, conveyed in 

 the manner of damps, or vapours for that pur- 

 pofe. 



(2.) As to the queftion, Whether fuch an un- 

 metallic' earth may be found in other ores, I muft 

 own, it was the pyrites gave me the rirft hint of 

 this forts as in it I found fomething which could 



neither 



