Gilding on Glass.

The Scientific American 10, 3.9.1859

Dissolve in boiled linseed oil an equal weight of copal or amber, and add as much oil of turpentine as will enable you to apply the compound or size thus formed, as thin as possible to the parts of glass intended to be gilt. The glass is to be placed in a stove, till it is so warm as almost to burn the fingers when handled. At this temperature the size becomes adhesive, and a piece of leaf gold applied in the usual way, will immediately stick. Sweep off the superfluous portions of the leaf; and when quite cold it may be burnished, taking care to interpose a piece of india paper between the gold and the burnisher. It sometime happens, when the varnish is not very good, that by repeated washing, the gold occurs off; on this account the practice of burning it in is usually had recourse to. For this purpose, some gold powder is ground with borax, and in this state applied to the clean surface of the glass by a camel'-shair pencil; when quite diy the glass is put into a stove heated to about the temperature of an annealing oven; the gold burns off, and the borax, by vitrifying, cements the gold with great firmness to the glass; after which it may be burnished.