202 E.. W. Root on Enargite from California. 
a residue of sulphur and antimonous acid. Soluble in aqua 
regia with a separation of sulphur. q 
Associated with the specimen submitted to analysis, wasa 
little iron pyrites and quartz, while the magnet extracted a few 
small shining particles, which before the blowpipe gave the — 
reactions for iron and titanic acid. 4 
n the quantitative analysis of the mineral a special portion — 
was taken for the sulphur determination; it was decom f 
upon a waterbath with fuming nitric acid, which even in the — 
presence of antimonous acid readily converted the sulphur into 
sulphuric acid, the solution evaporated to dryness, nitric acil — 
tet by hydrochloric, and the sulphuric acid precipitated 8 — 
usual. | . 
centrated solution of sulphurous acid in water, to reduce th 
_ arsenic to arsenious acid, and copper, arsenic and antimony pl 
cipitated as sulphids by hydrosulphuric acid. The moist sik 
phids were digested upon a waterbath with sulphid of pot 
sium, which dissolved out the sulphids of arsenic and antimon) 
The residue, consisting of the sulphid of copper was dissolve 
in nitric acid, converted into the sulphate, and the coppet 4 
cipitated in the metallic state by hypophosphite of mag ‘th . 
according to Gibbs’s method.* The solution ee a 
arsenic and antimony as double sulphids with sulphid o| 
tassium, was diluted with water, treated with a concent 
solution of sulphurous acid in water to an acid reattn a 
boiled in a large glass flask for several hours. Both the i 4 
phids of arsenic and antimony were at first precipitated | ‘. 
upon boiling, the sulphid of arsenic was converted into a 
ious acid. e sulphid of antimony was filtered off, wah oF 
of sulphur removed by repeated treatment with bis 
carbon, converted into the antimoniate of antim 
SbO,) by the action of fuming nitric acid, an 
* This Journal, II, xliv, 210. one has let 
_+ Bunsen, the originator of this separation of arsenic and antie acid aioe 
simplified the estimation of the arsenic, by converting the arse the solution ° 
into arsenic acid, by passing a current of chlorine gas through the : 
urs. 
