These oxides of copper were used as external applications in cases of polypi of the nose, diseases of the anus, ear, mouth, &c., seemingly as escharotics.
Ærugo, verdigris, was a subacetate of copper, doubtless often mixed with subacetate of zinc, as not only copper but brass also was used for preparing it. The mode of preparing this substance was similar to the process still followed. Whether verdigris was employed as a paint by the ancients does not appear; for Pliny takes no notice of any such use of it.
Chalcantum, called also atramentum sutorium, was probably a mixture of sulphate of copper and sulphate of iron. Pliny’s account of the mode of procuring it is too imperfect to enable us to form precise ideas concerning it; but it was crystallized on strings, which were extended for the purpose in the solution: its colour was blue, and it was transparent like glass. This description might apply to sulphate of copper; but as the substance was used for blackening leather, and on that account was called atramentum sutorium, it is obvious that it must have contained also sulphate of iron.
Chalcitis was the name for an ore of copper. The account given of it by Pliny agrees best with copper pyrites, which is now known to be a sulphur salt, composed of one atom of sulphide of copper (the acid) united to one atom of sulphide of iron (the base). Pliny informs us, that it is a mixture of copper, misy, and sory: its colour is that of honey. By age, he says, it changes into sory. I think it most probable that native sory, of which Pliny speaks, was sulphuret of copper, and artificial sory sulphate of copper. The native sory is said to constitute black veins in chalcitis. Pliny’s description of misy (μισυ) best agrees with copper pyrites. Dioscorides describes it as hard, as having the colour of gold, and as shining like a star.[44] All this agrees pretty well with copper pyrites.
Scoleca (so called because it assumed the shape of a worm) was formed by triturating alumen, carbonate of soda, and white vinegar, till the matter became green. It was probably a mixture of sulphate of soda, acetate of soda, acetate of alumina, and acetate of copper, probably with more or less oxide of copper, &c., depending upon the proportions of the respective constituents employed.
Such are the preparations of copper, employed by the ancients. They were only used as external applications, partly as escharotics, and partly to induce ulcers to put on a healthy appearance. It does not appear that copper was ever used by the ancients as an internal remedy.
4. Though zinc in the metallic state was unknown to the ancients, yet as they knew some of its ores, and employed preparations of it in medicine, and were in the habit of alloying copper with it, and converting it into brass, it will be proper to state here what was known to them concerning it.
Pliny nowhere makes us acquainted with the process by which copper was converted into brass, nor does he seem to have been acquainted with it; but from several facts incidentally mentioned by him, it is obvious that their process was similar to that which is followed at present by modern brass-makers. The copper in grains is mixed with a certain quantity of calamine (cadmia) and charcoal, and exposed for some time to a moderate heat in a covered crucible. The calamine is reduced to the metallic state, and imbibed by the copper grains. When the copper is thus converted into brass, the temperature is raised sufficiently high to melt the whole: it is then poured out and cast into a slab or ingot.
The cadmia employed by the ancients in medicine was not calamine, but oxide of zinc, which sublimed during the fusion of brass in an open vessel. It was distinguished by a variety of names, according to the state in which it was obtained: the lighter portion was called capnitis. Botryitis was the name of the portion in the interior of the chimney: the name was derived from some resemblance which it was supposed to have to a bunch of grapes. It had two colours, ash and red. The red variety was reckoned best. This red colour it might derive from some copper mixed with it, but more probably from iron; for a small quantity of oxide of iron is sufficient to give oxide of zinc a rather beautiful red colour. The portion collected on the sides of the furnace was called placitis: it constituted a crust, and was distinguished by different names, according to its colour; onychitis when it was blue externally, but spotted internally: ostracitis, when it was black and dirty-looking. This last variety was considered as an excellent application to wounds. The best cadmia in Pliny’s time was furnished by the furnaces of the Isle of Cyprus: it was used as an external application in ulcers, inflammations, eruptions, &c., so that its use in medicine was pretty much the same as at present. Sulphate and acetate of zinc were unknown to the ancients. No attempt seems to have been made by them to introduce any preparations of zinc as internal medicines.
Pompholyx was the name given to oxide of zinc, sublimed by the combustion of the zinc which exists in brass. Spodos seems to have been a mixture of oxides of zinc and copper. There were different varieties of it distinguished by various names.[45]