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lently on it, thefe phoenomena ought not to be 

 conrounded with each other. 



SECT. XXXIII. 



The ores be-ng thus calcined, the metals con- 

 tained in them may be difcovered, either by being 

 melted alone, or with fluxes : when they fhew 

 themfelves, either in their pure metallic ftate, or 

 bv ringing the flag with colours peculiar to each 

 of them. In thefe experiments it is not to be ex- 

 ftecTed, that the quantity of metal contained in 

 the ore mould be exact ly determined ; this muft 

 be done in larger laboratories. This cannot, how- 

 ever, be 1c >ked upon as any defect, finceit is ef- 

 ficient for a m;neral:ft, only to find out what fort 

 oi metal is contained in the ore. There is ano- 

 ther CMrcumftmcc, wHich I am forry to fay, is a 

 more real defect in cur little laboratory, which is. 

 that fome ores are not at all able to be tried in it, 

 by fo final! an apparatus : for inftance, the gold 

 ore caiied Pyrites aureus, which confifts 'of gold, 

 iron, and fulphur. The greater: quantity of gold, 

 which this ore contains, is about one ounce, or 

 one ounce and an half out of one hundred pounds 

 of the ore, the reft being iron and fulphur; and 

 as only a very fmall bit is allowed for thefe experi- 

 ments, (Sect. xvi. xxxi.) the gold contained there- 

 in, can hardly be decerned by the eye, even if it 

 could be extracted, but it goes along with the 

 iron in the flag, this laft metal being in fo large a 

 quantity in proportion to the other, and both of 

 them having a commicible power with each other. 



All the kinds of Blende, Blackjack, which are 

 rnineraiifed z:nk ores, containing zink, fuiphur, 

 and iron, cannot be tried this way, because thpv 

 car.not be perfectly calcined, and befides^ the zink 



flies 



