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of {hells, feathers, and hair, and that of the skin of thehuman species in certain climates, is only a superficial teint.The blackness of fruits, as already observed, is generallyrather a concentration of some other colour than a trueblack. Some woods, particularly the ebony, are tingedthroughout with a true blackness, on which great part oftheir value depends, and which art very happily imitateson more common woods. The bony matter which linesthe mouth of certain whales has likewise frequently apretty deep black tincture, joined to another quality,elasticity, on many occasions more important than itscolour.

Among the various substances which nature has im-pregnated with a deep and permanent black colour, thereare few of which art can avail itself for communicatingthis colour to other bodies. There is not perhaps any in-stance of a black colour being, as the rest of the coloursfrequently are, extracted from one body by means of dis-solvents, and thence introduced into another. Nor canthe generality of natural blacks be applied in their wholesubstance; some of these bodies being of such a texture,as does not admit of their being reduced into sufficientlyfine powder, for being mixed with a proper cementitiousmatter, so as to be spread smooth; and others having theircolour destroyed by the pulverization. Of these last wesee an instance in the common black states, which may bescraped into a white dust, in which the slightest scratcheslook white, and which, when drawn along any other blackbody, as hard as themselves and not polished, leave awhite mark; a property which, while it renders them ut-terly unfit for any purposes in painting or staining, is thaton which their use depends for occasional writing, or formaking pencils tor writing on other stones. It is obvious,that for this intention, black stones are better adapted than

those