FR00FS OF THE PROPERTIES OF GOLD.

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Experiment VIII.

A solution of gold stains animal and vegetable matterspurplish red.

If a solution of gold be applied to bone, ivory,-wood, feathers,linen, silk, lire, a stain will be left of a purplish-red colour,which 'cannot be effaced, on account of the strong attractionsubsisting between the oxid of gold and the substance to whichit is applied. The traces arc first purple, they afterwards becomeof a beautiful brown, and at last black. Hence a diluted solutionof gold may be used for painting upon silk.

Experiment IX.

Gold may be separated from its combinations with other metalsby sulphur et of antimony.

Put the alloy into a crucible with two parts of sulphuret of an-timony, and when the mixture is in perfect fusion, take the cru-cible out of the fire and suffer it to cool; a sulphuret will beformed with the foreign metals at the upper part, and the goldwill be found united to the antimony at the bottom of the cru-cible.

The gold may be separated from the antimony by bringing itto a white heat, by which means the antimony is volatilized.

Experiment X.

Gold when united to mercury is easily oxidated.

Put mercury with a forty-eighth part of its weight of gold intoa flat-bottomed matrass, the neck of which must be drawn outinto a capillary tube, and expose the mixture to heat in a sand-bath ; the metals will become oxidated and be converted into adark-coloured powder.