The best method of obtaining a coating resembling patina is to immerse
the article in a solution of nitrate of copper, and then to place it
while still wet in a chamber containing an abundance of carbolic acid.
In this case the development of the green incrustation may be observed
from day to day. If after a week the object has not yet obtained the
proper colour, it must be again dipped in the above solution, and this
operation is repeated till the desired shade has been acquired. As the
formation of this green colour proceeds in the same way as in the open
air, but more rapidly, a handsome and permanent coating of green can be
produced by this means.