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a large quantity at first, the precipitation is repeated afourth time.

The several metallic masses, thus precipitated, are to begranulated, sulphurated, and further concentrated by thesame precipitants as before; about an eighth part of leadbeing added, before the granulation, which is said to ren-der the mixt more fusible, and promote the separationof the gold. It is probable that bismuth would answerbetter in this intention, as it forms both with the metalsand with the sulphur a much more fusible compound thanlead does, and possesses also all the other properties of leadthat appear to be here required.

The matter which now subsides is again granulated,mixed with a sixteenth of sulphur, kept in fusion abouthalf an hour, the scoria poured off, and the remainingmass treated in the same manner, without any precipitant,a second or a third time. The gold being now so far con-centrated as to exhibit a yellow colour, the mass is meltedwith a sixteenth of copper, then granulated, the grainsmixed with a sixteenth of sulphur, cemented for sometime in a heat below ignition, after which, the fire beingraised, the matter is kept in fusion about fifteen minutes,and then poured out into a greased and heated mould: thegold is found at the bottom, commonly of a brass colour,and about the fineness of eighteen carats : if too pale, thelast operation is repeated with half the quantity of copper;after which the gold is further refined by antimony asalready described.

VII. Extraction of gold from copper.

For separating gold from large proportions of copper,as from the gilt clippings left by the button-maker, someof our refiners have recourse to cupellation or testing withlead. But the long continuance of fire and great quantity5 of