cf the Pyrites. 249 



(3.) From univerfal crude earths it is with 

 difficulty that ores can be exhibited, the con- 

 trary of which one might be apt to imagine 

 from the opinion of fuch earths being the 

 mother of ores, and the fulphur and arfenic 

 with their codtion, the father, or impregnating 

 principle. Examine the matter, as I have re- 

 peatedly done, but in vain, with fulphur, a thing 

 otherwife powerful and efficacious, on well puri- 

 fied and prepared ochre, which already, along 

 with fulphur, was an ore, that is, a pyrites-, or if 

 you fufpect it fallen, by the vitriolifation, to a 

 form quite irreducible and foreign to the defign, 

 take llime, marl, loam, clay, and leaving out the 

 tenderer!:, unchangeable, and mildeft earths, try 

 any how, with fulphur, to accomplifh an impreg- 

 nation of ore : though it cannot be denied, that 

 to the production of metals, particularly of iron 

 and filver, by means of fulphur, not only the earth 

 of one of its parts, namely, its fatty portion, but 

 of its. whole fubftance, is really fitted; as, by a 

 due degree of appropriation and incalefcence, it is 

 not only made operative, but, by a proper length 

 of time, may be made permanent ; but this lad 

 operation requires the hand of an able mafter. 



(4.) From feme metallic calces, or earths, that 

 were actually metallic, ore may be again made, as 

 appears from the genuine glajjy ore, which, from 

 the faline filver-calx, when fmelted along with ful- 

 phur, nay, foftly, and for a continuance thorough- 

 ly warmed therewith, ufually appears in a drufy 

 form. 



(5.) From fiiver itfelf, without previous reduc- 

 tion to an earth, there is again procurable with the 

 addition of fulphur, or rather cinnabar (as the fulphur 



