or to restore such as may have become discolored by time or other circumstances, the process called Improving is adopted, and this differs in no essential particular from staining, excepting that its object is merely to improve the color and bring out the natural grain of the wood itself, instead of attempting to make it represent another from which its veining may entirely differ. Barberry root boiled in water, Gamboge or Turmeric dissolved in spirit, give good yellow stains adapted for the purpose. A good red oil for rubbing discolored mahogany or rosewood, or for deeping the color of bay-wood, may be made in the following manner: Tie up some Alkanet-root in a muslin bag, and let it soak over night in some sweet oil. The oil which is then pressed from the bag will impart a beautiful red color to all the rest. The grain of the wood is well brought out by its being rubbed with ammonia before the oil is applied. Rectified naphtha, colored with Camwood dust, is another good red tint. Discolored ebony may be improved by washing over it a strong decoction of gallnuts in which a quantity of steel filings has been immersed, this liquid should be allowed to stand a day, and should then be carefully strained, and, as before stated, a little indigo should be added to the French polish. Raw oil mixed with a small quantity of turpentine serves to improve most woods when well rubbed into them, and this may be greatly enhanced in value by grinding up with it a small quantity of the color which it is desired to impart to the wood, or by mixing with it oil previously colored in the manner already described.
The well-known pigment called Gamboge is a gummy and slightly resinous exudation from the young wood of the Gamboge-tree. Though not a dye-stuff. Gamboge is much used in coloring, forming a valuable water-color, and is also used in coloring lacquer for varnish for brass-work. There is some reason to believe that Gamboge is made from more than one species. There are three kinds of Gamboge:
