Black, Composi′′tion (zĭsh′-ŭn-). The selected portion of the residuum of the process of making prussiate of potash from blood and hoofs. Used both as a pigment and to decolour
organic solutions, which it does better than bone-black.
Black, Cork′. Spanish-black.
Black, Flo′′rey, Florée d’Inde. The dried scum of the dyer’s wood-bath. A superior blue-black.
Black, Frank′fort, Noir de Francfort. From vine-twigs dried, carbonised to a full black, and then ground very fine. An excellent black pigment; also used by the copper-plate printers to make their ink. See Blue-black.
Black, Harts′horn. Resembles ivory-black, which is now usually sold for it. It was formerly prepared by carbonising the residuum of the distillation of spirit of hartshorn.
Black, I′vory. Syn. Car′bo eb′oris, E′bur us′tum ni′grum, L.; Noir d′ivoire, &c., Fr.; Elfenbeinschwartz, Kohle von elfenbein, Ger. From waste fragments and turnings of ivory, by careful exposure in covered crucibles, avoiding excess of heat or over-burning. The whole having been allowed to become quite cold, the crucibles are opened and their contents reduced to fine powder. For the first quality only the richest coloured portion of the charcoal is selected, and this, after being powdered, is ground with water on porphyry, washed on a filter with warm water, and then dried. A very rich and beautiful black. It is brighter than even peach-stone black, and is quite free from the reddish tinge of bone-black. With white-lead it forms a rich pearl-grey. See Bone-black.
Black, Jamai′ca (-mā′-). Sugar-black.
Black, Lamp′. Syn. Fuli′go lucer′næ, F. pi′nea, &c., L.; Noir de fumée, &c., Fr.; Kienruss, &c., Ger. Prep. 1. (On the small scale.) A conical funnel of tin-plate furnished with a small pipe to convey the fumes from the apartment, is suspended over a lamp fed with oil, tallow, coal-tar, or crude naphtha, the wick being large and so arranged as to burn with a full smoky flame. Large spongy, mushroom-like concretions of an exceedingly light, very black, carbonaceous matter, gradually form at the summit of the cone, and must be collected from time to time. The funnel should be united to the smoke-pipe by means of wire, and no solder should be used for the joints of either.
2. (Commercial.) On the large scale, lamp-black is now generally made by burning bone-oil (previously freed from its ammonia), or common coal-tar, and receiving the smoke in a suitable chamber. In the patented process of Messrs Martin and Grafton the coal-tar is violently agitated with lime-water until the two are well mixed, after which it is allowed to subside, and the lime-water having been drawn off, the tar is washed several times with hot water. After subsidence and decantation it is put into stills, and rectified. The crude naphtha in the receiver is then put into a long cast-iron tube furnished with numerous large burners, underneath which is a furnace to heat the pipe to nearly the boiling point. Over each burner is a sort of funnel which goes into a cast-iron pipe or main, which thus receives the smoke from all the burners. From this main the smoke is conveyed by large pipes to a succession of boxes or chambers, and thence into a series of large canvas bags arranged side by side, and connected together at top and bottom alternately. Fifty to eighty of these ‘bags’ are employed; the last one being left open to admit of the escape of the smoke, which has thus been made to traverse a space of about 400 yards. As soon as the bags contain any considerable quantity of black they are removed and emptied. The black deposited in the last bag is the finest and best, and it becomes progressively coarse as it approaches the furnace.