Those desirous of inquiring further into the knowledge which the ancients had of this metal must examine the meaning of the word _cadmia_, which seems to have had various significations. This task I have ventured to undertake; and though I cannot clear up everything that occurs respecting it, I shall lay before my readers what information I have been able to obtain on the subject, because perhaps it may amount to somewhat more than is to be found in the works of old commentators. _Cadmia_ signified, then, in the first place, a mineral abounding in zinc, as well as any ore combined with it, and also that zinc-earth which we call calamine. Those who should understand under it only the latter, would not be able to explain the greater part of the passages in the ancients where it is mentioned. It is probable that ore containing zinc acquired this name, because it first produced brass[84]. When it was afterwards remarked that calamine gave to copper a yellow colour, the same name was conferred on it also. It appears, however, that it was seldom found by the ancients[85]; and we must consider _cadmia_ in general as signifying ore that contained zinc. Gold-coloured copper or brass was long preferred to pure or common copper, and thought to be more beautiful the nearer it approached to the best _aurichalcum_. Brass therefore was supposed to be a more valuable kind of copper; and on this account Pliny says that _cadmia_ was necessary for procuring copper, that is brass. Copper, as well as brass, was for a great length of time called _æs_, and it was not till a late period that mineralogists, in order to distinguish them, gave the name of _cuprum_ to the former[86]. Pliny says that it was good when a large quantity of _cadmia_ had been added to it, because it not only rendered the colour more beautiful, but increased the weight. In the like manner a quintal of copper in Hungary produces a hundred and fifty pounds of brass. The same author remarks also that the _cadmia_ (_fossilis_) was not used in medicine: this however is to be understood only of the raw ore, for some physicians prepared oxide of zinc from ore that contained zinc, as he afterwards tells us; and Galen extols the calamine found in Cyprus on account of its superior effects, because, perhaps, the oxide could be obtained from it much purer.