The following are brassing solutions. Water, 160 parts; copper cyanide, 2 parts; zinc cyanide, lpart; and potassium cyanide, 15 parts. Or water, 250 parts; copper sulphate, 1 part; zinc sulphate, 8parts; and potassium cyanide, 18 parts. Watt's solution is made by dissolving as much sheet brass as possible in warm dilute nitric acid, the fumes given off being poisonous. Next add this solution to water in the proportions of 2 oz. of brass per gallon of water, and add strong liquid ammonia until a deep blue colour results. Add strong solution of potassium cyanide until a pale yellow colour is obtained. Filter this, and finally add water so that the proportion is loz. of brass to 1 gal. of the solution. This solution, which can be used hot or cold, should be kept some hours before use.