The mixture of lime and copper solution is made in the proportion of 100 lb. dry lime with 175 dry copper salt, if the most intense coloration is desired, but the proportion of lime may be much increased without detriment to the pigment beyond lessening its intensity of colour. After complete settlement of the precipitate, the clear liquor is decanted; the pigment is carefully washed with clean soft water, and drained on filter cloths till it is of a convenient consistence forming a green paste. A definite weight of this paste calculated on the dry pigment is taken for further incorporation, consequently it is first necessary to ascertain how much water is in the paste. Usually it amounts to 75 per cent., and on this basis 5 lb. of the paste are stirred up with 1 gal. clean water in a lead-lined vat, with addition of ½ lb. wet lime under constant agitation. Subsequently ¼ pint of clear solution of best potash at 15° B. is well stirred in, and the mixture is immediately taken to the mill and most thoroughly ground. Further, for each 10 gal. of green paste is prepared a clear solution of 1 lb. pure salammoniac in 2 gal. water and another solution of 2 lb. copper sulphate in 2 gal. water. The liquid paste is drawn off from the mill into a stoneware vessel, and the two solutions of salammoniac and copper sulphate are immediately added. After complete agitation and combination, the mixture is left for 4 or 5 days to settle, and turned into a lead-lined vat, where it is repeatedly washed with clean waters until turmeric paper is not discoloured.