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be recovered by distillation from the liquor which remainsafter the gold has fallen.

Kunckel is the first who has taken notice of this pre-cipitation by vitriol: but having used a vitriol whichpartook of copper as well as iron, he seems to havethought that the effect depended on the copper, andrecommends the bluest and most venereal of the commonforts of vitriol as the best : accordingly most of those,who have mentioned this process, direct blue vitriol orvitriol of copper. I have not found that blue vitriol pro-duces the least precipitation in solution of gold ; so that,by this misapprehension in regard to the nature of theprecipitant, Kunckel’s discovery was rendered useless, tillBrandt happily observed, that green vitriol produces theeffect which had been ascribed to the blue.

VI. Extradlion of a small portion of gold from a largequantity of fiver.

The most advantageous method of separating a smallproportion of gold from a large one of silver appears tobe by means of sulphur, which unites with and scorifiesthe silver, without affecting the gold. But as sulphuratedsilver does not stow thin enough to suffer the small particlesof gold, diffused through it, to reunite and settle to thebottom, some addition is necessary for collecting and car-rying them down.

In order to the commixture with the sulphur, fifty orsixty pounds of the mixt metal, or as much as a largecrucible will receive, are melted at once, and reduced intograins by lading out the fluid matter, with a small cruciblemade red hot, and pouring it into cold water stirred witha rapid circular motion. From an eighth to a fifth of thegranulated metal, according as it is richer or poorer ingold, is reserved; and the rest well mingled with an

Y eighth