266 Of the Principles 



iron-vitriol -, as the iron -pyrites is not only the mod 

 common fort of pyrites, but of ores too •, fo that, 

 preferably to other minerals, it fhould feem to be 

 ferviceable for yielding fumes and damps for the 

 production and generation of new ores. 



3. Some other circumflances are here to be con- 

 fidered, by which we may have a nearer view of 

 the manner of pyritification, v or mineraliiation in 

 general. 



(1.) We are not to imagine thefe ore- damps, 

 which at length end in the form of the pyrites, al- 

 ready to contain the parts of the pyrites, as iron, 

 copper, fulphur, and arfenic, but only to confider 

 them as a feed. This is matter of fact ♦, the proof 

 clearly appears from the enumeration of the feveral 

 circumflances above, therefore I fhall only men- 

 tion the texture of this ore, which is fo fmooth and 

 even, fo undiflinguifhable, fo uniform in the mix- 

 tion of its parts, as if run or caft together, and 

 hence in its ground-work, of the mod tender 

 mixtion, and fuch a form, as'can never be imagined 

 of damps, containing the parts of the intended 

 whole, without forming too grofs a notion of the 

 mineral principles. 



Yet this comparifon of animal and vegetable 

 feeds mud not be carried too far, as if the body of 

 the pyr ties, grown from its feed, could from its 

 own fubftance enlarge and encreafe : but here hap- 

 pens, firft, an accumulation, in the courfe of 

 which, an elaboration commences at the fame 

 time ; by means of which the matter gradually ap- 

 proaches to the intended body -, and fo long as it is 

 Hill receptive, or if you had rather, feminal and 

 foft, fo long it ftill receives the tranfient damps, 



which 



