of the P YR ITES. IJ 



CHAP. III. 



Of the feveral Species of the Pyrites. 



pYRIfES, or kies, in the fenfe we are to 

 take it, is a mineral or ore, partly white- 

 grey, partly yellowilh grey, partly brafs-yellow ; 

 having for its conftituent principles a metallic, 

 namely, an iron earth, which is its proper character- 

 iftic -, a volatile matter, as either fulphur or arfenic, 

 or both, tho' the former prevails more frequently ; 

 fome forts are found to partake largely of copper, 

 with which is generally found a mixture of filver, 

 but in a very lmall quantity, and fometimes an ap- 

 pearance of gold, tho' this is rather imaginary. 

 The pyrites are commonly worked for fulphur, 

 arfenic, fandarach and vitriol, the laft of which, 

 ought not to be looked upon as an original 

 principle, but as a production confequent of the 

 combination of the other principles. 



The parts of the pyrites may alfo be confidered 

 as they are either effential or incidental. With re- 

 flect to the former, there is properly in nature 

 no more than one fort of pyrites \ for in all there 

 is iron, and this iron is the primary conftituent 

 part ; every pyrites being an iron earth, either 

 lulphurated, or arfenicated, or participating of both 

 at the fame time. In an incidental view, pyrites 

 are diftinguifhed, i. with regard to their metallic 

 contents. 2. Their fulphur and arfenic. The for- 

 mer may be divided into iron and copper pyrites* 

 the denomination being here taken from what 

 conftitutes the greateft part of this compofition. 

 At Friberg, the copper-pyrites denote fuch as yield 



C one 



