104 Of the Iron 



that thofe pyrites, which, with us at Friberg, give 

 only a few pounds of copper, are no longer called 

 pyrites absolutely, but copper pyrites ; and that thofe 

 containing ten, twenty, thirty, and more pounds of 

 that metal the quintal, ceafe to be called pyrites, and 

 take the appellation of copper-ores ; that, however, 

 many, nay, mod pyrites, with us at Friberg, are 

 not purely martial, having fome fmall matter of 

 copper in them : but, in fact, I foon difcovered 

 the above affertion to have all the juftnefs and foli- 

 dity that any other propofition in mineralogy could 

 . pofiibly claim : and my experience in pyrites has 

 been fo extenfive, that, without hefitation or re- 

 ierve, I may aver, all the.forts of them, the white, 

 the yellowijh and yellow, in regard of metal-yield, to 

 confift either entirely of, or to hold iron in equal 

 quantity ; or mould the iron be exceeded by the 

 copper, yet ftill to maintain its rank as a confli- 

 tuent part thereof. 



Therefore 1 afTert more than what, I think, the 

 above authors have done, namely, that iron con- 

 iiitutes the ground-earth of all forts of pyrites •, a 

 truth to be met with in no other author that I am 

 acquainted with, though no great art be requifite 

 for making the difcovery, being what is eafily 

 found by only the magnet; a circumftance that 

 feems to do no great honour to our care and at- 

 tention, as thus the moft common and obvious 

 things often efcape our knowledge -, not to men- 

 tion the fubtilities and empty fpeculations of phi- 

 lofophers, who, overlooking the information of 

 the fenfes, rather confound than clear up mat- 

 ters. 



The Heffian pyrites from Almerode, called ter- 

 ra martis Hajfmca, and Solaris, but from what hea- 



veo 



