t 3 2 ° ]

of the colour; which, if it be a true black, will in thisdiluted state look of a pure or simple grey, but if it has atendency to any other colour, that colour will now betrayitself.

11. All the colours, in a very deep or concentrated state,approach to blackness. Thus the red liquor prepared byboiling or infusing madder root in water, and the yellowdecoction or infusion of liquorice root, evaporated in agentle heat till they become thick, look of a dark blackcolour, or of a colour approaching to blackness j and thesethick masses, drawn out into siender strings, or diluted withwater, or rubbed on paper, exhibit again the red and yel-low colours, which the liquors had at first. Nature affordsmany black objects, whose blackness depends upon the fameprinciple, being truly a concentration of some of the othercolours. Thus in black cherries, currants, elderberries, 6 cc.what seems to be black is no other than an opake deepred : their juce appears black when its surface is lookeddown upon in an opake vessel, but red when diluted orspread thin. The black flint, as it is called, of the islandof Ascension, held in thin pieces between the eye and thelight, appears greenish ; and one of the deep black stonescalled black agate, viewed in the fame manner, discoversits true colour to be a deep red.

SECT. II.

Native black colours.

r ~ | ^ H E mineral kingdom affords abundance of bodiesJL uniformly tinctured or variegated with black, or witha deep colour approaching to blackness: Such are, the blackslates, which make an ornamental covering for houses:the black touchstone, on which pieces of metals beingrubbed leave a mark of their own colour; which strews the

colour