ner described, p. 70, having
previously acidulated the wine with muriatic acid.

The wine test sometimes employed is prepared in the following
manner:--Mix equal parts of finely powdered sulphur and of slacked
quick-lime, and expose it to a red heat for twenty minutes. To
thirty-six grains of this sulphuret of lime, add twenty-six grains of
super-tartrate of potassa; put the mixture into an ounce bottle, and
fill up the bottle with water that has been previously boiled, and
suffered to cool. The liquor, after having been repeatedly shaken, and
allowed to become clear, by the subsidence of the undissolved matter,
may then be poured into another phial, into which about twenty drops of
muriatic acid have been previously put. It is then ready for use. This
test, when mingled with wine containing lead or copper, turns the wine
of a dark-brown or black colour. But the mere application of
sulphuretted hydrogen gas to wine, acidulated by muriatic acid, is a far
more preferable mode of detecting lead in wine.

M. Vogel[39] has lately recommended acetate of lead as a test for
detecting extraneous colours in red wine. He remarks, that none of the
substances that can be employed for colouring wine, such as the berries
of the Vaccinium Mirtillus (bilberries), elderberries, and Campeach
wood, produce with genuine red wine, a greenish grey precipitate, which
is the colour that is procured by this test by means of genuine red
wines.

Wine coloured with the juice of the bilberries, or elderberries, or
Campeach wood, produces, with acetate of lead, a deep blue precipitate;
and Brazil-wood, red saunders, and the red beet, produce a colour which
is precipitated red by acetate of lead. Wine coloured by beet root is
also rendered colourless by lime water; but the weakest acid brings back
the colour. As the colouring matter of red wines resides in the skin of
the grape, M. Vogel prepared a quantity of skins, and reduced them to
powder. In this state he found that they communicated to alcohol a deep
red colour: a paper stained with this colour was rendered red by acids
and green by alkalies.

M. Vogel made a quantity of red wine from black grapes, for the purpose
of his experiments; and this produced the genuine greyish green
precipitate with acetate of lead. He also found the same coloured
precipitate in two specimens of red wine, the genuineness of which could
not be suspected; the one from Chateau-Marguaux, and the other from the
neigh