Note 308 — COLOURED GLASS.—ARTIFICIAL GEMS.
William Johnston translation
Strabo, Amst. 1707, fol. lib. xvi. p. 1099.—Some consider the glass earth here mentioned as a mineral alkali that was really found in Egypt, and which served to make glass; but, as the author speaks expressly of coloured glass, I do not think that the above salt, without which no glass was then made, is what is meant; but rather a metallic oxide, such perhaps as ochre or manganese.