The gold-seeker's manual / By David T. Ansted.

  • David T. Ansted
Date:
1849
Catalogue details

Licence: Public Domain Mark

Credit: The gold-seeker's manual / By David T. Ansted. Source: Wellcome Collection.

    126/190 page 118
    of the dust (say 100 grains) may be digested with aqua regia (nitro-hydrochlorie aeid), and the solu- tion being preci])itated with protosulj)hate of iron and fused with nitre and borax, the residue is the old eontained. The silver in this case will remain on the filter in the form of a white powder (chlo- ride), and the platina may be precipitated by hy- drochlorate of ammonia. Tlie reduction of gold ores is effected either by amalgamation with mercury or by fusion with lime and a dux—the former being the method usually adopted when the ores contain a fair ])roportion of native gold, and the latter in the case of auri- ferous pyrites. Amalgamation, in the former case, is thus performed:— The ore, having been pounded fine, is washed, to separate as much of the light stony matter as possible, which is done either with a machine (tailed a sweep-washer, or more simply by placing the pounded ore in a shallow vessel with two handles, which, when immersed in a tub of water or running stream, and a kind of rotatory motion applied, separates the lighter from the heavier ])articles. The residue left from the washing is to be dried and mixed with a sufficient quantity of mercury to amalgamate the gold and silver eontained; to fa^mur which, a gentle heat may be applied to the mass for two or three days, at the
    digitised image 1
    digitised image 2
    digitised image 3