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 brass84. 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 ancients85; 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 former86. 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.
In the second place, cadmia, among the ancients, was what we call (ofenbruch) furnace-calamine, or what in melting ore that contains zinc, or in making brass, falls to the bottom of the furnace, and which consists of more or less calcined zinc. As this furnace-calamine assumes various appearances, according to the manner of melting, and according to many other circumstances that in part cannot be defined, and as the ancients comprehend all its varieties under the general name of cadmia, and give to each variety, according to its form, consistence and colour, a particular name also, a confusion of names has hence arisen which cannot now be cleared up, especially as it is not thought worth while to distinguish all its incidental variations. Our physicians esteem only the pure oxide of zinc; and as they know how to obtain it, they are not under the necessity of using impure furnace-calamine. In our melting-houses it is employed, without much nicety in the choice, for making zinc or brass87.
What here appears to me most singular is, that the ancients should have given the same names to furnace-calamine as they gave to ores that contained zinc. The affinity of these substances they could conjecture only from their effects, or perhaps they were induced to do so from observing that furnace-calamine was not produced but when the different kinds of cadmia, as they were called, were melted; that is, when yellow and not red copper was obtained. Ofenbruch got the name of furnace-calamine at Rammelsberg, when it was observed that it could be employed instead of native calamine for making brass88. Were the ancients then in any measure acquainted with this use of it? Galen and Dioscorides speak only of its use in medicine, and say nothing of its being employed in the preparation of brass. The Arabian writers, particularly the translators of the Greek physicians, speak in a much clearer manner of the preparation of brass; but the appellations which they employ are so indeterminate in their signification, that an answer to the above question cannot be deduced from them. Climia, which some pronounce calimia and from which the modern Greeks made kelimia, and the Latins lapis calaminaris, seems to have entirely the same meaning as cadmia. Tutia, which occurs first in the eleventh century, in Avicenna, and which the Greeks write toutia, or perhaps more properly thouthia, signifies sometimes pompholyx; but in common it seems to express also minerals that contain zinc, and likewise furnace-calamine89. Could it be proved that the tutia of the Arabs and later Greeks was furnace-calamine, or the tutia of our druggists, the oldest account with which I am acquainted of furnace-calamine, employed in making brass, would occur in Zosimus, who, according to every appearance, lived in the fifth century90. This author tells us, that in order to make brass, Cyprus copper must be melted, and pounded tutia must be strewed over it. Salmasius suspects that Zosimus here means only calamine: but however this may be, his receipt has been retained till the present time in books on the arts; for these recommend not calamine, but tutia91.
We can with more certainty affirm that this use of furnace-calamine, in making brass, was known to Albertus Magnus in the thirteenth century; for he says, first, that yellow copper was made by the addition of calamine, which he calls lapis calaminaris. He tells us afterwards, that Hermes taught how to give a gold colour to copper by throwing pounded tutia into the melted metal. Tutia, says he, which is used in the transmutation of metals, is not a native mineral, but an artificial mixture, produced in the furnace when copper-ore is melted; and he advises glass-gall to be strewed over the ore, otherwise calamine and tutia will lose their force in the fire92. It would appear that the last-mentioned name, in the thirteenth century, signified only furnace-calamine, and that its use for making brass was at that period known.
For many centuries, however, the ofenbruch (furnace-calamine), with which, as we are told, the furnaces at Rammelsberg overflowed, was thrown aside as useless, till at length, in the middle of the sixteenth century, Erasmus Ebener first showed that it might be used instead of native calamine for making brass. This Ebener, descended from the noble family of that name at Nuremberg, was a man of great learning, and an able statesman. He was employed by his native city, and by foreign princes, on occasions of the highest importance. In 1569 he was privy-counsellor to Julius duke of Brunswick, and died in 1577, at Helmstadt, where he was buried. I regret much that I can give no further account of this important discovery; the time even when it was made is not known with certainty. Lœhneyss says that it was sixty years before the period when he wrote. But at what period did he write? The oldest edition, with which I am acquainted, of his treatise on mines, is of the year 1617, so that this discovery would fall about the year 155793. Calvör caused to be printed an old account of the Rammelsberg mines, which was said to have been published in 1565. According to that work, Ebener made the above-mentioned observation at Nuremberg, about seventeen years before, that is, about the year 1548. Schluter assigns as the period about 1550, and Honemann about 1559. We may therefore very safely place it in the middle of the sixteenth century, and probably the discovery happened in 1553, at which time Ebener was sent to duke Henry, with whom he continued a long time, as we are expressly told by Doppelmayer. This use of calamine refuse induced the managers of the profitable brass-works in the Harz forest to pick up carefully that which before had been thrown aside. Duke Julius, who endeavoured to improve every branch of manufacture, and particularly what related to metallurgy,