ioo Of the Iron 



hilpbur flags , to be worked for fandarach, fo as to 

 quit the trouble. In the arienical fort, a ftoney 

 ir o?i -earth is the principal and large ft portion ; and 

 what is called the fly /lone, the fecond and laft; 

 with the observation, that whereas the fulphur in 

 the firft fort makes a fourth in refpecl of the iron-, 

 here at Friberg the arfenic in the mijfpickel com- 

 monly makes a third •, and at the Obergeburge, 

 often a full half, in refpect of the remaining irony, 

 quartzy matter. Nay, the abovementioned black, 

 arienical, foffiie matter, otherwife to be found 

 near red-goldijh ore, but particularly pure, without 

 the like accompanying rich filver-vein, in a mine 

 near Schwartzenberg, and there alfo called poiflon- 

 pyrites, alfo teftaceous cobald, contains neither iron, 

 nor any other earth, but in the fire fublimes in its 

 entire fubftance, and thus proves a pure arfenic, 

 or foffiie fly -ft one. But here the name is mifap- 

 plied, if we abide by the definition of pyrites^ 

 namely, its being an ore, confiding either in a 

 fulphurated or arfenicated metallic earth ; whereas 

 this, on the contrary, can fnew nothing, either of 

 a metallic, or other earth. On thefe feveral con- 

 ftituent parts of the pyrites, I mail take notice of 

 what I take to be fubfervient to my principal 

 view. 



To begin with iron, as the principal conftituent 

 part of the pyrites. In general, it deferves to be 

 remarked of that metal, that it confifts of a me- 

 tallic earth, proximately arifing, above all others, 

 from the crude, undetermined earth itfelf ; as, 

 among other things, appears from the following 

 obfervations. (i.) In moifture, particularly in the 

 moift earth, it very eafily turns to a ruft, confe- 

 quently to an earth ; which can be faid of no other 

 metal, but lead an-d copper, which change, the 



one 



