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ANALYSTS OF ORES OF GOLD.

oxid of lead or litharge, enabling it likewise to form a similarkind of substance with the other metals in the alloy. Thisglassy fluid soaks into the pores of the cupel, while the remain-ing mixture of gold and silver is left behind in the vessel: thesilver is then separated from the gold as before, by parting.

It must be observed, that every alloy of gold is supposed to bedivided into twenty-four parts, called carats, and that the purityof gold is estimated according to the number of those parts,which it makes up.

The gold coins of Great Britain are composed of 11 parts ofgold, and 1 of copper; they are therefore gold of twenty-twocarats.

Perfectly pure gold may be obtained by dissolving the gold ofcommerce in nitro-muriatic acid, and precipitating the metal byadding a weak solution of sulphate of iron. The precipitate afterbeing well washed and dried, is pure gold.