Bistre
This is a brown color ing them in water with a little soda or potash, which is used in water-color painting. It is and adding alum to the strained liquor as long prepared from the root of beech-wood by as a precipitate is thrown down. Or by washing away the soluble parts with water. The insoluble residue is mixed with gum wa- be combined with 1/8 ounce of soluble iodine ter and formed into cakes. violet, and the wool immersed in the solution