| VI.— | Corrosive sublimate | 25 parts |
|---|---|---|
| Potassium nitrate | 86 parts | |
| Borax | 56 parts | |
| Zinc oxide | 113 parts | |
| Copper acetate | 220–225 parts |
Mix and heat together on the surface of the object under treatment.
VII.—Brown.—The following is a Parisian method of producing a beautiful deep brown:
| Potassium oxalate, acid | 3 parts |
| Ammonium chloride | 15 parts |
| Water, distilled | 280 parts |
Mix and dissolve. The object is penciled over with this several times, each time allowing the solution to dry before putting on any more. The process is slow, but makes an elegant finish.
Green Patina Upon Copper.
Black Patina.
Blue-black Patina.
Red Patina.
If it is desired to produce a marbled surface, instead of an even red color, borax or some chemical having a similar action is sprinkled upon the metal during the process of heating. On the places covered by the borax, oxidation is prevented, and after polishing, spots of the original metallic color will appear in the red surface. These can be colored by well-known processes, so as to give the desired marbled appearance.