The charcoal made in this way is very pure. After washing, grinding and drying, it forms a pigment whose shade leaves nothing to be desired. The drying must be conducted at a low temperature; charcoal in such a fine state of division is very easily inflammable. _Vine Black from Pressed Grapes._—The material contains the stems and pressed remains of the grapes after the must has been expressed. After-wine, spirits or vinegar can be obtained before it is used for vine black. The process is exactly the same as for wine lees. The charcoal taken from the tubes has rather more coherence than that made from lees and must be ground. The black is a very useful pigment, but is inferior to the black from lees. In regard to the latter, it should be stated that it is a particularly good black pigment, and when finely ground is as well suited for the preparation of the finest blacks, such as are used in copper-plate printing, as the far more costly soot black. The black from grape residues, or from grapes themselves (the poor grapes removed in pruning the vine are used), can be employed with advantage for many purposes for which the best black is not necessary. The greater number of the pigments sold under the names of Frankfort and Paris black consist of this substance. =Bone Black or Ivory Black.=—Bone black, for of ivory black only the name now exists, is distinguished by a peculiar quality which it owes to the structure of the raw material from which it is made. This raw material is animal bones, which largely consist of incombustible materials (bone ash); these form a delicate framework whose interstices are filled by organic matter. When bones are carbonised, the carbon resulting from the decomposition of the organic matter is deposited on the incombustible framework of bone ash and thus acquires a very great surface. Carbon is well known to possess very powerful absorptive properties, which are especially developed in bone black, in consequence of its fine division. The use of granular bone black (known as ”char”) in sugar works, and generally for decolourising liquids, is due to the peculiar state of division of the charcoal. For these purposes bone black is used in enormous quantities; it is made in special works. It does not fall within the scope of this work to give a detailed description of the manufacture of bone black, and we must here restrict ourselves to matters of special interest to the colour maker.