METALLIC SULPHURRTS, HI 



oxigen, it is evident that the latter could not efcape the at- 

 traction of the combuftible fubflance in a high temperature. 



When treated with carbon, pyrites produces only fulphur- 

 ated hidrogen ; but if firft deprived of 12 or 20 hundredths of 

 of fulphur, it prefents only fulphuret, or iron faturated with 

 fulphur, in the proportion of 60 to 100. It is foluble in the 

 fulphur ic, muriatic, and dilute nitric acids, affording fulphur- 

 ated hidrogen in abundance. 



Pyrites, therefore, according to thefe refults, is nothing more Pyrites is a ful« 

 than a fulphuret formed by nature in the humid way, and fur- cha/Wwith 

 charged with an excels of fulphur, as if to enfure the duration fulphur. 

 of her work. 



The pyrites will undoubtedly be found to differ greatly from They differ 

 each other with refped to this excels of fulphur ; for, accord- T^ jjjttft 

 ing to Henkel, there are fbme which yield 25,28, even 32 plus by diftilla- 

 per cent, of fulphur. It is therefore to this furplus that the tion# 

 product of this diltillation belongs, and not to the fulphur, 

 which has been combined with iron by the invariable law of 

 the proportions ; for the metal, when faturated with -j%% of 

 this combuftible, yields none on being expofed to that tempe- 

 rature which deprives the pyrites of its excefs. ' 



The pyrites, befides their different known ufes, are of great Ealy method of 

 ufe in a laboratory. We may fill a crucible with them, cover P rocurin g hidr °- 

 the powder with about a third part of filings, fprinkle over 

 thefe a little charcoal powder, and afterwards bring the whole 

 to a red heat, without carrying it fo far as to reduce them to 

 the ftate of fufion. In this manner we obtain a homogeneous 

 mafs, very convenient for procuring hidrogen in abundance. 



By what I have juft laid, I do not however mean to imply The lead ful- 

 that all the pyrites refemble each other. Thofe, for example, Pirated pyrite* 



i • rr J r ..... r are fooneft vi- 



vvhicn poflels the property of becoming vitnohzed, approach triolized. 

 perhaps the neareft to the fulphuret of iron without excefs ; 

 for it is certain that the pyrites moft charged with fulphur are 

 at the fame time thofer which refill the tendency of the ele- 

 ments to deftroy them the longelt. 



Thepyr.ites of Soria contains a little chalk, fand, and argill, 

 but not the flighteit trace of copper : its folution in the nitric 

 acid is reduced to the minimum of oxidation by means of ful* 

 phurated hidrogen ; and the yellow powder which fepacates 

 from it is nothing but fulphur. t 



The 



