Chap. 35.] Separation of Gold from bajer Matters. 229 



and very little for arfenic, which are the ufual mine- 

 ralizers of t Metallic bodies, it is not furprizing that it 

 ihoulti be ufihJiy ^ound in a feparate and nearly pure 

 ftate. The metaili-- bodies, wich which it is alloyed 

 in a ftate of nature, fcldom conftitute any confiderable 

 part of its weight; they are generally either filver, 

 copper, or iron. Gold, however, is fometinnes mixed 

 wich martial pyrites, and is fometimes contained in an 

 ore, which is a mixture of lead, filver, and iron, mi- 

 neralized by fulphur. In thefe cafes the prefence of 

 gold is not known by the appearance of the mineral, 

 and can only be difcovered by roafting, and fubfequent 

 fufion with fuch matters as are capable of vitrifying 

 the earthy and martial fubftances. The addition of 

 icad is alfo ufeful, which unites with the gold, and 

 carries it to the bottom of thj mak. The gold is 

 eafily obtained free from the lead by the proceU of cu- 

 .peilation. 



In order to feparate gold, when in its native ftate, 

 from the earthy and ilony matters in which it is .con- 

 tained, the following procefs is employed: When it 

 is contained in fand, the lighter particles of the latter 

 are wafhed away by water, and the remaining matter, 

 which may prove fo heavy as not to be feparated from 

 the gold without danger of lofing fome of the precious 

 metal, are amalgamized, by being ground with mer- 

 cury, in the fame manner as has been mentioned in 

 the extraction of filver. Jf the gold is mixed with 

 flones of confiderable bulk, it is neceflary that they 

 mould be reduced to powder in order to render them 

 fufficiently light to be wafhed away. The mercury 

 is alfo feparated from gold in the fame way as from 

 filver ; as much as poflible is feparated from it by pref- 

 fure in bags of leather, and the remainder by heat. 



All the imperfect metals may be abftra&ed from 



gold 



