226 Elements of Mineralogy. 



PART IV. 



Metallic SubJIances. 



I. |V/f ETALLIC fubftances are opake 

 ***' bodies, whofe fpecific gravity ex- 

 ceeds 5,000, confirming of a heavy, dull, 

 brittle earth combinable with phlogiilon, and 

 during that union pofifeffing a peculiar fhining 

 appearance. They are all conductors of 

 electricity, and more perfectly fo than any 

 other bodies during their union with phlo- 

 gifton. They are all foluble either in the 

 nitrous acid, or in aqua regia, and all preci- 

 pitable in fome degree by cauftic alkalis, and 

 (except platina) by the P ruffian alkali ; all 

 when dephlogifticated communicate a tinge 

 to borax or microcofmic fait when melted 

 1 with thefe fluxes, or render them opake ; all 

 melt in fome degree of heat, and moft com- 

 monly affume a convex furface, or if in fmall 

 quantity a globular form when in fufion, 

 and in that ftate are mifcible with each other 

 for the moft part, but refufe to unite with 

 any other unmetallic fubflance, even their 

 own calces * ; but when calcined they are 



* Iron is an exception to this rule, for even in its re- 

 guline ftate it is capable of uniting to its own calces flightly 

 dephlogifticated, and to plumbago : fome of them alfo may 

 contain fulphur even in their regulme flate as nickel, &c. ' 



capable 



