98 ON A METHOD OF EXTRACTING GOLD, SILVER, 
Tt is difficult to account for the fact, that in the case of the 
in chlorine, and that as a mispickel dissolves gold, it was there- 
fore obtained in the residue in a finely divided ate less so in 
the iron pyrites resid, and tout divided in the complex ore. 
In the last, mere traces of gold were ear by retraaiitig the 
residues from the first hess haath by chlorine. 
to render their use possible for its extraction are the auricyanides 
of the alkali metals and bromide of gold. romine wild ow- 
A expensive and more troublesome to use than 
chlorine, and m in one or two trials gaye me smaller 
with tincture of iodine. . I have been unable to obtain any reaction 
either with tincture of iodine or with solution of iodine in iodide 
of potassium, which, considering the oo e character of the 
id iodi ly to be w 
ere 
gration and Bilnevt have observed that precipitated 
gold is pobabies in om fee of potassium if ex to t a! air, ‘ au nud 
i use for this On eau the reaction rae a pre- 
cipitated gold and cyanide of potassium, I found that it was 
extremely slow if the gold was at all dense. In presence of 
ae of 7a aoe or binoxide of manganese, all the po was 
dissolved ; with chromate of pote assium, a small ee with 
acco ing to the e uation— 
4Au + 2K,FeCy, + 70+ 40,0 = sandy + FeO; + ene 
* Chem. News, xx1I, 245. + Watt’s Dict.: Cyanides of Gold. . 
ia ae ees ho ee ees 
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