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Turnbull's Prussian Blue

be decanted, and the carmine that has been Ferricyanide (red prussiate) of potassium, 10 deposited at the bottom collected, and placed ounces; solution protosulphate of iron, 1 pint; water, 3 pints. Dissolve the ferricyanide of potassium in part of water, and add the solution, gradually, to the solution of protosulphate of iron previously diluted with the remainder of the water, stirring the mixture during the addition. Then filter the liquid, upon a filter to drain. When it has acquired the consistence of a paste, remove it from the filter with an ivory or silver knife, and finish the drying upon shallow plates, covered with silver paper. 2678. To Make Carmine by Cenette's Process. The following is the method emand wash the precipitate on the filter with ployed by Madame Cenette: Finest cochineal, boiling water until the washings pass nearly reduced to powder, 2 pounds; pure river watasteless. Lastly, dry it, and rub it into fine ter, boiling hot, 15 gallons; boil for 2 hours, powder. It may also be made by adding protosulphate of iron to a mixture of yellow prussiate of potash, chloride of soda, and hydrochloric acid. This, mixed with water, makes an excellent bluing. then add refined saltpetre, bruised, 3 ounces; boil for 3 minutes longer, and add 4 ounces of salts of sorrel (binoxalate of potassa).

Boil for 10 minutes longer, then remove the heat, and allow the liquor to settle for 4 hours,