tn the Pyrites. 183 



lour as a white fmalt, ufually employed in ena- 

 melling ; and, to my mind, almoft fuch another 

 mafs as that arifing from running alum and com- 

 mon fait together, for the preparation of Glau- 

 ber's fait, 



Whether it be a real fait, I fhall as little dis- 

 pute as believe, feeing it does not partake of the 

 genuine properties of a fait, being neither foluble 

 in water, nor peculiarly affecting the tongue: the 

 trueft conception we can form thereof, confifts in 

 confidering it a calcined metallic body; as, in its 

 origin, it exhibits a metallic body, which is here • 

 only a little difguifed, but again recoverable upon 

 the addition of the metallic portion, which hap- 

 pened to be burnt out. In the courfe of the re- 

 fining, it rifes like a white fume, and fettles, at 

 firft, as a white powder, which, as the heat gra- 

 dually encreafes, 'till the fubliming veffel be made 

 of a thorough glow, cakes and runs to a clofe, 

 glaffy body. 



Arfenicum cryftallinum flavum, yellow cryftalline 

 arfenic, is, in its principles, nothing elfe but the 

 above white fort, and in the very fame manner 

 brought to that form •, only that fome fulphur hap- 

 pens to ftain its beautiful milky colour with a call 

 of yellow •, and though, properly, not fo tranfpa- 

 rent as a frefh white fort, yet, in its fubflance, it 

 is mining and glaffy, like a yellow fmalt, or ena- 

 mel, though by far more beautiful. 



Arfenicum rubrum, red arfenic, differs from the 

 yellow only in being more richly dofed with ful- 

 phur, and, confequently, has a greater degree of 

 opacity, and a lefs glaffy appearance ; for the reft, 

 'tis an arfenic in ground, and popularly called fan- 



N 4 daracb; 



