Green, Neuwieder. Schweinfurt green mixed with gypsum or sulphate of baryta.
Green, Prussian. The sediment of the process of making Prussian blue from bullock’s blood or horns, before it has had the hydrochloric acid added to it. It is also prepared by pouring liquid chloride upon freshly precipitated Prussian blue. As now sold, this pigment is generally a mixture of Prussian blue and gamboge.
Green, Rinman’s. This resembles that of Gellert.
Green, Sap. A very fugitive pigment, prepared from the juice of buckthorn berries. The berries are allowed to ferment for a week or eight days in a wooden tub. The juice is then pressed out, strained, a little alum added, and the whole evaporated to a proper consistence;
it is next run into pigs’ bladders, and hung up in a dry situation to harden. An inferior article is made from the juice of black alder, and of evergreen privet. It is a common practice to add 3⁄4 pint of lime water and 1⁄2 oz. of gum Arabic to every pint of either of the above juices.
Green, Scheele’s. This is arsenite of copper.
Prep. 1. White arsenic (in powder), 1 part; commercial potash, 2 parts; boiling water, 35 parts; dissolve, filter, and add the solution gradually, whilst still warm, to a filtered solution of sulphate of copper (cryst.), 2 parts, as long as a precipitate falls; lastly, wash the newly formed pigment with warm water, and dry it.
2. (Ure.) Powdered arsenious acid, 11 oz.; carbonate of potassa, 11⁄2 lb.; boiling water, 1 gall.; dissolve, filter, and add the solution, as before, to another solution of crystallised sulphate of copper, 2 lbs., in water, 3 galls. Prod. 11⁄2 lb. A very fine grass-green colour.
Green, Schweinfurt. This splendid green pigment is the aceto-arsenite of copper.
Prep. 1. Acetate of copper and arsenious acid, equal parts, are each dissolved separately in the least possible quantity of boiling water, and the solutions mixed whilst still as hot as possible; an olive-green precipitate falls, which, by being boiled in the liquor 5 or 6 minutes, changes to a dense granular powder of a superb green colour.