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ceive their various Colours from the Differences as well of their Properties of acting on other Bodies[1], as of their being ſubject to be acted on by them. Some of theſe they ſoften, and others melt, and afterwards reduce to Powder; and from theſe compoſe the ſtony Maſſes which we receive from Aſia.
CVII. But the native, which have their Uſe as well as Excellence, are only three or four; the [2]Melian, the
- ↑ The high-colour'd Earths uſed by Painters, and in Medicine, owe their ſeveral Colours, in a great Meaſure, to the ſame Cauſe as the Gems, &c. do theirs; a Mixture of metalline Matter of various Kinds, which ſtains them, as it does thoſe, with the Colour it naturally yields, in the particular kind of Solution its Particles have met with. Thus Copper, diſſolved in a proper Alkali, makes, with a proper gemmeous Matter, a blue Sapphire; and with Earth, the Lapis Armenus, a Subſtance before deſcribed. And the ſame Particles diſſolved in a proper Acid, give to gemmeous Matter the Colour which makes it an Emerald; and to Earth, that which makes it the Terre verte, an Earth uſed by our Painters, of a duſky greeniſh Colour, and denſe, unctuous, clayey Conſtitution; generally brought from Italy, but to be met with entirely as good here at Home: And Iron, which gives that glorious Red to the Ruby, the Garnet, and the Amethyſt, with Earth, makes the red Boles, Ochres, and Clays.
- ↑ The Melian Earth of the Antients was a fine white Marle, of a looſe crumbling Texture, and eaſily diffuſible in Water or other Liquors. Some have imagined it to have been of other Colours; but that it was really white, we have the unqueſtionable Authority of the Antients: Pliny not only deſcribes it to be ſo, in his general Account of it, but afterwards confirms it in another Chapter, where he ſays it was the White of the great Painters of Antiquity: Lib. 35. c. 6. ſpeaking of it among
