MORDANT

is also the name sometimes given to the adhesive matter by which gold-leaf is made to adhere to surfaces of wood and metal in gilding. Paper, vellum, taffety, ., are easily gilt by the aid of different mordants, such as the following: 1. beer in which some honey and gum arabic have been di olved; 2. gum arabic, sugar, and water; 3. the viscid juice of onion or hyacinth, strengthened with a little gum arabic. When too much gum is employed, the silver or gold leaf is apt to crack in the drying of the mordant. A little carmine should be mixed with the above colourle liquids, to mark the places where they are applied. The foil is applied by means of a do il of cotton wool, and when the mordant has become hard, the foil is polished with the same. The best medium for sticking gold and silver leaf to wood, is the following, called mixtion by the French artists:—1 pound of amber is to be fused, with 4 ounces of mastic in tears, and 1 ounce of Jewish pitch, and the whole di olved in 1 pound of linseed oil rendered drying by litharge. Painters in distemper sometimes increase the effect of their work, by patches of gold leaf, which they place in favourable positions; they employ the above mordant. The manufacturers of paper hangings of the finer kinds attach gold and silver leaf to them by the same varnish.