tn the Pyrites. 185 



Moreover, as fulphur appropriates the quickfilver 

 to itfelf, and quits the arfenic, fo it keeps in a 

 jufter proportion with the former, than with the 

 latter > it, in one cafe, bearing more and Jefs, al- 

 moft in the proportion of the dofe given, whatever 

 that be •, and in the other, being incapable of re- 

 ceiving either more or lefs, the proportion being 

 conftant, a circumftance worthy of notice. 



Red at fenic ', or fandarach, may be made from 

 pure ore, and fuch pyrites alone, wherein the ful- 

 phur and arfenic are together in a fufricient quanti- 

 ty ; or from pyrites-additions, or dolings, fo that 

 the one (hall fupply what the other wants; or from 

 poifon-meal and fulphur-pyrttes ; or from arfenic- 

 pyrites and fulphur-flags, that is, the arfenical ful- 

 phureous refidue procured from crude fulphur: but 

 the attempting to make it from white cryftalline 

 arfenic and actual fulphur, either does not fucceed 

 at all, or with great difficulty: whence appears, 

 (1.) the fomewhat coy or repelling nature of the 

 white cryftalline arfenic; (2.) how much the che- 

 mical combinations depend on the appropriation*, 

 congruencies, or aptitudes, alfo on the diverilty of 

 the matters, when employed in their unprepared 

 and native ftate, directly from. their matrices and 

 natural admixtures •, fo that red arfenic is not a 

 thing, in its ground- fubftance or principles, di* 

 ftinguimablc from the white, as fome falfely ima- 

 gine. 



Thus we have exhibited arfenic in all its various 

 appearances, from its firft fly-ftone Mate, to that 

 wherein 'tis fitted for common ufe, and thus from 

 huts to the (hops : and not only io, but we 

 here teach how to reduce it back again 10 ail the 

 forms it had before undergone ; in particular, w 11s 



fi It, 



