172 GOLD. 
It was anciently the custom to beat gold into thin 
plates, and to gild the walls of apartments, the surfaces 
of dishes, drinking utensils, and other articles, by co- 
vering them with such. But this was not only an expen- 
sive, but it must have been a most clumsy mode of 
ornament. The present modes of gilding are very dif- 
ferent. When wood is to be gilded, the surface is first 
smeared with an adhesive kind of oil, or with a kind 
of glue called size ; and the gold leaf, above mentioned, 
is then spread upon it by a tuft of cotton or other 
soft substance. 
The gilding of iron or copper is performed by clean- 
ing and polishing its surface, and then heating it till it 
has a blue colour. When this has been done, a layer of 
gold leaf is put on, slightly burnished down, and ex- 
posed to a gentle fire. It is usual, in common work, to 
place three such layers, or four at the most, each con- 
sisting of a single leaf. The heating is repeated at each 
layer, and last of all the work is burnished. For gild- 
ing in or mottluy as it is denominated by the French, an 
amalgam consisting of ten parts of mercury and one 
part of gold is used. This is spread upon the metal, 
and is afterwards exposed to the action of a fire suffi- 
ciently strong to evaporate the mercury and leave the 
gold behind. The gilding in or moulu is much more 
solid and permanent than that by the former method. 
When gilding is pale and dirty, it may be revived by 
means of what is called gilding wax, a composition of 
yellow wax, bole (127), verdigris (230), and alum. 
A very beautiful gilding upon metals, and particularly 
upon silver, is effected by soaking clean linen rags in a 
solution of gold made by aqua regia (207). The rags are 
dried and burnt ; and the ashes are carefully preserved. 
These ashes are used by taking a sound cork, moisten- 
ing it with a little water, dipping it into the ashes, and 
then rubbing strongly a portion of them on the surface 
of the silver, which should be perfectly clean and bright. 
By this simple and economical process, it will be cover* 
