Note 1223 — BOOK XXXIV. THE NATURAL HISTORY OF METALS.

Pliny again refers to this mineral in the 22d Chapter. We have no means of ascertaining, with certainty, what is the substance to which this name was applied by the ancients. The ores of copper are very numerous, and of various chemical constitutions: the most abundant, and those most commonly employed in the production of the pure metal, are the sulphurets, more especially what is termed copper pyrites, and the oxides. It has been supposed, by some commentators, that the Cadmia of the ancients was Calamine, which is an ore of zinc; but we may be confident that the Æs of the ancients could not be produced from this substance, because, as has been stated above, the Æs contains no zinc. I must, however, observe that the contrary opinion is maintained by M. Delafosso.—B. See Note 1216 above.