of the Pyrites. 271 



mercurification. But, whether the arfenic, after 

 reparation from the pyrites, that is, in arfenic- 

 meal, fiy-ftone, orcryftalline arfenic, be fit for this 

 purpofe, I leave thofe to determine, who confider 

 incidental circumftances and appropriations, as fo 

 many empty notions, and who underftand not the 

 importance of the difference between bodies, as ftill 

 in their native mixed date, and as in their feparated. 



With refpect to the queftion, whether fome- 

 times ore- veins may be found, where the ore-pro- 

 du&ion is in fieri* an d not actually formed : if this 

 be underftood of the accumulation of ore, there is 

 no manner of doubt, but that ore is produced on 

 ore •, and a vein, a fibre, may be fo filled up as to 

 receive neither this nor any other fort of ore-damp ; 

 and thus the vein, that hitherto was but in fieri, 

 comes now to be compleat. But ore is certainly 

 generated, and that damp-wife ; but damp-wife 

 productions imply furely an accumulation. But 

 fhould the queftion regard the ground-mixtion of 

 the ore itfelf -, the mod experienced can neither 

 fhew the places and nefts, where the ore-forming 

 fpirit broods, nor the ore in its eggs and feeds. 

 Further, neither can the gurs, or metallic juices, 

 whether from deftroyed pyrites, weathered ores, or 

 from macerated, luty, marly, (limy, fpathy, and 

 calcarious (tones and earths, claim any place here. 

 And tho' in this cafe our want of experience is to 

 be lamented, yet it is probable, that after all our 

 enquiries, we mail find neither eggs nor brood, but 

 be forced to own, that pyrites, and all other ores, 

 do in the courfe of the conception, or of lodging 

 the ore-damp in its matrix, arrive to their perfec- 

 tion by a fpeedy coction and maturation ; if the ac- 

 cumulation itfelf be not the mixtion, 



CHAP. 



