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 brass[87]. 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 brass[88]. 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-calamine[89]. 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 century[90]. This author tells us, that in order to make brass, Cyprus copper must be melted, and pounded _tutia_ must be strewed over it.