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as in colder, for in the hot it emits a Kind of Humidity out of its Subſtance, which runs all over it: This hinders the metalline Particles from adhering perfectly, and makes Miſtakes in the Trials. This Exſudation of a humid Matter is alſo common to many other Stones; among others, to thoſe of which Statues are made; and this has been looked on as peculiar to the Statue.
LXXXI. Theſe then, in general, are the Differences, and particular Qualities of Stones.
LXXXII. Thoſe of Earths are fewer, indeed, but they are alſo more peculiar.
LXXXIII. [1]Earth is ſubject to be
- ↑ The Author now enters on an Account of the various Earths. The Differences of which are, indeed, very eſſential. It is to be obſerved, that he ſets out in his uſual Manner, juſtly, and philoſophically. The two great Characteriſtics of Earths, are their eaſy Diffuſibility in Water, and Concretion and Induration on being ſeparated from it; and their being fuſible by Fire. The firſt of theſe Qualities eſſentially diſtinguiſhes them from moſt
a very circumſtantial Account of the Property of this Stone; and they had in his Time very good ones, and knew very well how to uſe them, if they could do what he ſays with them. The true Lydius, tho' perfectly black, is a real Kind of Serpentine. Its Structure is the very ſame with the common green and white Serpentine; and there, is a green and black one, the black Parts of which. are perfectly like it.
