102. CHANGING VARNISHES
Varnishes of this description are call changing because, when applied to metals such as copper, brass, or tin or silver foil, they give them a more agreeable colour; indeed, the common metals, when coated with them acquired a lustre approaching to that of the precious metals, and hence these varnishes are much employed in manufacturing imitations of gold and silver. Put four ounces of the best gum gamboge into 32 ozs. of spirits of turpentine, 4 ozs. of dragon's blood into the same quantity of spirits of turpentine as the gamboge, and 1 oz. of anatto into 8 ozs. of the same spirits. The three mixtures being made in different vessels, they should then be kept for about a fortnight in a warm place, and as much exposed to the sun a possible; at the end of that time they will be fit for use; and you can procure any tints you wish by making a composition from them, with such proportions of each liquor as practice and the nature of the colour you are desirous of obtaining will point out. Changing varnishes may likewise be employed, with very good effect, for furniture, such as picture frames, &c.—See Lackers.