Ammonio-carbonate of Copper.

As carbonate of copper is not kept in stock by the chemists it has to be made, which can easily be done, as follows: In a wooden tub dissolve 3lb. sulphate of copper in 4 gals, hot water. In another vessel dissolve 3½lb. common washing-soda in 1 gal. hot water. When cool pour the second solution slowly into the first; then, as soon as all action has ceased, add water enough to bring the whole up to 8 or 10 gals., and stir thoroughly. In twenty-four hours pour off the clear liquid, taking care not to disturb the sediment; add fresh water, and stir again. In another twenty-four hours pour off the clear liquid as before. The sediment remaining is carbonate of copper—impure, certainly, but suitable for our purpose. This paste may be immediately dissolved in aqua ammonia, strength 26° Baume—2 gals., or perhaps a little more, may be necessary. This concentrated fluid must be kept in well-corked jars, and it is ready for use at any time by diluting at the rate of 1 pint to 12 gals, water. Or the paste itself may be used, mixed in the proportions of 5oz. in 25 gals, water. In this case the mixture must be kept constantly stirred up, or the carbonate of copper will quickly settle to the bottom.