FALLEN OK THE EARTH. 91 



rites from the infbluble earthy matter, the fubtra&ion of which 

 reduced the weight of real pyrites to 14- grains. I next ob- 

 tained the fulphur, by filtration. When it was as dry as I 

 could make it, without fear of its being fublimcd, its weight 

 was two grains. To the filtrated liquor 1 added nitrate of ba- 

 rytes, by way of detecting any fulphuric acid which might have 

 been prefent ; but no cloudinefs enfued. 1 then feparated, 

 by fulphate of ammonia, the barytes thus added, and precipi- 

 tated the iron with ammonia. The liquor, on the fubfidence The metals wcra 

 of oxide of iron, appeared of a violet purple colour : it con- * ir .°" a^ fane 

 tained 'nickel, which I threw down with fulphureted hidrogen 

 gas, there being already a fufficient excefs of ammonia in the 

 faline liquor to form an alkaline hidrogenized fulphuret. The 

 oxide of iron, after ignition, weighed 15 grains; and the ful- 

 phuret of nickel, reduced to an oxide, weighed, after the 

 fame treatment, fomething more than one grain. The pro- 

 portions of the fubfrances contained in the pyrites of the ftone 

 from Benares, may therefore be confidered nearly thus . 



Grains. 

 Sulphur 2 Component 



Iron - - - - - J0| parts, fulphur, 



.-,,.,- r . , much iron, nic- 



Smce 15 grains of the oxide repreient about that quan- k t \ t an d earth. 



dtyofiron, 



Nickel, nearly I 



Extraneous earthy matter - 2 



15i 



It is obfervable that, notwithstanding the lofs appears to be Remark,, 

 only half a grain, it was probably more, becaufe the fulphur 

 could not be reduced to the fame ftate of drynefs in which it 

 exifted when in combination with the iron ; not to fay that it 

 was, in a fmali degree, volatilized with the hidrogen gas dif- 

 engaged during the folution. 



The weight of nickel is a mere efrimation. We are not yet 

 fufficiently acquainted with that metal to fpeak of it with ac- 

 curacy, except as to its prefence. Upon the whole, how- 

 ever, it may be concluded, that thefe pyrites are of a very 

 particular nature ; for, although Henkel has obferved that 

 fulphur may be feparated from pyrites by muriatic acid, it is 

 by no means the ufual habitude of pyrites to be of fuch eafy 

 decompofition. 



Thfc 



