LAKES (ante), oertain pigments made by combining vegetable or cochineal dyes with metallic oxides, usually alumina or tin. Carmine lake is made by adding an alkali to a decoction of cochineal and alum, and the residues and mother liquors, which are produced in the preparation of carmine, are used for this purpose; hut a carmine lake was made at Florence from Kermes mineral before cochineal was brought to Europe. Violet and purple lakes are made by adding a solution of alum to a decoction of logwdod and precipitating in the cold by carbonate of potash. Yellow. lakes are prepared in various ways. Dutch pink is made from Persian berries by making a decoction of them with potash or soda solution, and adding alum solution as long as a precipitate takes place. The addition of a solution of chloride of tin brightens the solution. Fustic lake is made by adding to a decoction of the wood glue or skimmed milk to remove the tan nic acid. Alkali is added to remove acidity, and then the precipitation is accomplished by alum solution. Quercitron and wild lakes are made by similar processes. Orange
lakes are made from arnotto or turmeric by similar processes. Blue lakes are prepared by adding sulphate of copper (blue vitriol) to a solution of logwood and precipitating in the cold with potash, or by precipitation with carbonate of potash from a solution of sulphindigotic acid and abuts. Green lakes may be prepared by mixing blue or yellow lakes with blue or yellow pigments, or they may be made by a primary process. A decoction of coffee berries with sulphate of copper yields a good green lake by the addi tion of a moderate quantity of caustic potash. The addition of acetic acid heightens the color. Lakes are often adulterated by adding such substances as gypsum and white clay. A good e'e will detect the adulteration at once from the loss of brilliancy, but a chemical test will detect the lime base in the gypsum or the silica in the clay.