METALS. 
655 
then dipped in water, and the wax cleaned off with the wire 
brush and beer. 
For a still higher colour, the work is afterwards spread 
over with a paste composed of equal parts of sal ammo 
niac, saltpetre, blue vitriol, and a half part of crystallized 
verdigris, made up with water, and then heated till it 
smokes; after which it is treated as with the gilder’s wax. 
Dead yellow gilding, presenting a frosted surface, with 
out any polish, and of a beautiful yellow colour, is pro 
duced by a saline preparation formed of six ounces of salt 
petre, two of copperas, and one each of white vitriol and of 
verdigris. The work being covered with this paste, is 
thrown into weakened aquafortis, and the ebullition pro 
duces the dead or matted appearance. 
The following alloys of copper are used at Birmingham 
for gilding upon. Four parts of copper, melted with one of 
Bristol, or pale yellow brass, and then remelted with 14 
ounces of tin to each pound of copper that was used. For 
common articles, 3 parts of copper, 1 of Bristol brass, and 
4 ounces of tin, to each pound of copper. If the articles are 
to be highly polished, half the tin is taken away, and sup 
plied byregulus of antimony. If the articles are wished to 
be of a pale colour, half or even two-thirds only of the copper 
may be put in. Compound metals, nearly the colour of gold 
coin, which of course require but little gold for gilding, are 
made by melting 2 parts of Cheadle, or dark brass, 1 of cop 
per, with a little Bristol brass, and a quarter of an ounce of 
tin, to each pound of copper ; or 16 parts of tough cake 
copper, are melted with 5 of spelter or zinc. 
Plating of Copper with Gold. 
Ingots of copper or brass, are plated with gold for the 
purpose of rolling out into sheets, by first cleansing the 
surface of the copper, then placing a piece of gold upon it ; 
hammering it out to cover the surface ; binding it on with 
wire that it may not slip; soldering the edge of the gold 
plate with silver filings, mixed with borax, by exposing the 
ingot to a sufficient heat ; the ingot may then be rolled out 
into sheets. 
Cold Gilding of Copper or Brass. 
For cold gilding by friction, a fine linen rag is steeped in 
a saturated solution of gold, till it has entirely imbibed the 
liquor ; this rag is then dried over a fire, and afterwards 
burned to tinder. Now, when any thing is to be gilded, it