METHOD OF OBTAINING GOLD.

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ing it to a sufficient heat in a crucible, whereby the soda unitesto the muriatic acid, and sets the silver free.

When gold is found mixed with sulphur or arsenic, and othermetals, the ore must first be torrefied, which separates the greatestpart of the arsenic and sulphur, and then melted with iron, whichunites with what remains. The heterogeneous metallic sub-stances are then separated by scorification with fluxes, consist-ing of tartrite of potash and nitrate of potash, which have noeffect upon gold when the sulphur is previously separated - lm with-out this previous separation, the sulphur would unite with partof the alcali of the nitrate of potash, and form sulphuret of pot-ash, which would take up a portion of the gold, and thus dimi-nish the produce. The gold left by the melting w'ith the flux,is afterwards further purified by cupellation, or melting withlead.

When the gold ore is free from sulphur, it may after beingpounded and washed, be melted with one and a half part ofsemi-vitreous oxid of lead, and three parts of glass, in a cruciblecovered with muriate of soda. By this operation, all the hete-rogeneous metals will scorify, and set the gold free.