50 ft BEDS 



veins ; often entirely alone, as we have an un- 

 common inftance at Pretzfchendorff ; but for 

 the molt part it accompanies other veins, as 

 was above obferved ; fcarce ever without mock- 

 lead being included in the very heart of the py- 

 rites-dice, as we alfo learn from the Pretzfchendorff. 

 The pyritce fetting or reaching as low as levels have 

 hitherto been driven, or fhafts funk, often appear 

 to contain copper, but foon after afford only a pure 

 iron ; thus proceeding on, till by reafon of the 

 waters, they can no longer be traced. Of this 

 we have ocular demonftration from the Croner- 

 mine at Friberg, and from the territory of the 

 Tfcherpe and Hohenbirk, and an undeniable proof 

 from volcano's and fubterraneous accenfions ; as 

 their inflammable matter is probably, among other 

 things, derived from the pyrites ; which from fuch 

 mountains being unexhauftible, muft be diftributed, 

 not in a fcanty and fuperficial, but in a very plenti- 

 ful manner at unfathomable depths : and again, the 

 pyritte extend outwards quite to the under-turf earth, 

 or almoft to the day, tho' the other accompany- 

 ing minerals in the extremities, or firft begin- 

 nings, are wont to difappear or vanifh : or, con- 

 verfely, moil ore -veins manifeft themfelves from 

 without inwards firft of all by the pyrites ; affur- 

 ing the miner, from unexceptionable experience, 

 of his being either already upon, or not far off 

 a capital vein. 



2. The pyrites affect a fquat or horizontal bed, 

 as Jhiver '-mines fufficiently fhew •, the pyrites always 

 inclining to extend and ftretch laterally, which is 

 what we commonly call a fquat or flat vein. 

 Generally they are copper, very rarely iron py- 

 rites, that affect this fort of bed : and fuch pyrites- 

 fquats are commonly without any admixture of 

 other veins, as mock-lead, mifspickel, glitter, &c. which 

 is the reafon that die copper from Shiver-Mines 



