(2) Place 2 parts by weight of copper-filings in a vessel capable of being tightly closed, and over them pour 3 parts by weight of salammoniac in the form of a saturated aqueous solution. Keep the mixture in a warm place for some weeks and thoroughly agitate it occasionally. In due time the newly formed oxychloride is removed from the vessel, and separated from the non-oxidised copper by washing on a sieve. This washing must be continued until all traces of alkali have been destroyed, when the pigment is drained, and very slowly dried at a low temperature to avoid decomposition. (3) Copper scrap is covered with a concentrated solution of chloride of copper and allowed to remain until the chloride has undergone conversion into basic chloride. The latter is then subjected to the straining, washing, and drying treatment prescribed in (2). (4) In a lead-lined vessel, place a quantity of copper filings or waste, and add to it two-thirds of its weight of common salt, and one-third of its weight of concentrated sulphuric acid, the latter being however first diluted by admixture with three times its volume of water. The mass is left to stand, with occasional stirring till all the copper has been transformed into oxychloride, when it is strained, washed, and dried as in (2). (5) A modification of (4) is to put the copper scrap into a wooden vessel, and cover it with an equal weight of common salt and an equal weight of sulphate of potash dissolved in water. After standing and agitation as before, the oxychloride is formed, and the straining, washing, and drying are repeated. (6) A solution of crude carbonate of ammonia is added to a mixed solution of alum and blue vitriol so long as any reaction takes place. When it is completed, the precipitate is collected, washed, and dried as in the other cases. (7) Lighter shades are produced by the addition of alum, or of sulphate of baryta. (_b_) New process.