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Work, but are forced to lie along, either on their Backs or on one Side; for the Vein of the Earth they dig runs length-way, and is only of the Depth of about two Foot, though much more in Breadth, and is incloſed in on every Side with Stones, from between which it is taken. There is alſo in the Maſs of the Vein a diſtinct Stratum near the Middle, which is of better Earth than that without it; and within that there is ſometimes another yet finer; and even beyond that a fourth: The fartheſt of theſe is that which is called the Aſter.
ed, from its Colour, Collyrion, Κολλύριον. Κολλύρα among the Greeks ſignified a kind of Loaf baked in Aſhes, and uſually brought to the Colour of the Aſhes in the doing: And from a Reſemblance to this was this Earth called Collyrion, or the aſh-coloured Samian Earth.
Pliny imagined it had the Name from its being a common Ingredient in certain Medicines for the Eyes, commonly called Collyria; but Dioſcorides, from whom he took the Occaſion of this Conjecture, does not attribute this Quality to the Samian Earth of either kind, but to the Lapis Samius, a Stone found among it. And from this Error alone it is, that ſo many have imagined that the Samian Earth was uſed in Medicines for the Eyes. Indeed, when an Error in regard to the Antients is once ſet on foot, there is no knowing what a Series of different Miſtakes may be the Conſequences of it. Theſe Medicines for the Eyes, called Collyria, though they did not give the Name to the aſh-coloured Samian Earth ſo called, may ſerve, however, to confirm the Opinion of its having obtained it on occaſion of its Colour reſembling that of Aſhes; ſince they had theirs from the ſame Cauſe, and were
