Pliny the elder on gilding

The description in Pliny’s ‘Natural History’ of gilding bronze by using mercury becomes clearer if it is seen as a process in which mercury is used only as an adhesive for the gold leaf and in which it is not necessary to heat the object after gilding to drive off the excess mercury as is the case in the more usual fire- or mercury-gilding. Laboratory experiments on the techniques of gilding and a study of the older literature support this new interpretation and emphasise the importance of the purity of the substrate metal.