_The Processes of Browning._—A browning or rust may be obtained very speedily and well by enclosing the barrels in a chamber and subjecting them to the vapor of muriatic acid. The same end may be obtained by moistening the surface with dilute muriatic or nitric acid. There is another material sometimes used, which is butter or chloride of antimony. It is sometimes called “bronzing or browning salt.” In using this substance, a uniform mixture is made with it and olive oil; this is rubbed upon the barrel, which is slightly heated, and is then exposed to the air until the required degree of browning is arrived at. The operation of the antimony is quickened by rubbing on after it, a little aquafortis. _Browning Damascus Barrels._—Damascus barrels are browned by first burnishing the barrels very nicely, then cover with bone oil; pound, or drop, or strew wood ashes all over, then heat in a wire cage filled with charcoal, until the first dark blue is obtained. After the barrels are cold, mix a small quantity of sulphuric acid in water, and with a hard brush apply to the barrel. The acid will remove the color from the steel portion of the barrel, leaving the iron, on account of its greater adhesion, still retaining its blue color. Take care to keep a good color and not extract too much. _Browning Belgian Damascus Barrels._—The characteristic, bright, wavy appearance of Belgian Damascus barrels is generally “eat up,” and the process is termed “pickling.” The process results in eating away the softer metals from the harder, used in forming the barrel. The preparation used is one pound of blue vitriol dissolved in a gallon of soft water, at the boiling point, and the boiling continued until the quantity is reduced about one-fourth; then let it cool, and pour out into a lead trough. Plug the barrels securely at both breech and muzzle, so that the liquid cannot get into the interior. When the barrels are immersed in the solution, it will act upon the metal in fifteen to twenty minutes. Remove and wash with water, and if not satisfactory, immerse again, until the operation is complete. Pour boiling water over them, and scratch well with a steel brush or card, which will eventually give the beautiful, bright, wavy appearance. Laminated steel barrels may be subjected to this same operation.