The History of Chemistry. Thomas Thomson
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Copper was put by the ancients to almost all the uses to which it is put by the moderns. One of the great sources of consumption was bronze statues, which were first introduced into Rome after the conquest of Asia Minor. Before that time, the statues of the Romans were made of wood or stoneware. Pliny gives various formulas for making bronze for statues. Of these it may be worth while to put down the most material.
1. To new copper add a third part of old copper. To every hundred pounds of this mixture, twelve pounds and a half of tin37 are added, and the whole melted together.
2. Another kind of bronze for statues was formed, by melting together 100lbs. copper, 10lbs. lead, 5lbs. tin.
3. Their copper-pots for boiling consisted of 100lbs. of copper, melted with three or four pounds of tin.
The four celebrated statues of horses which, during the reign of Theodosius II. were transported from Chio to Constantinople; and, when Constantinople was taken and plundered by the Crusaders and Venetians in 1204, were sent by Martin Zeno and set up by the doge, Peter Ziani, in the portal of St. Mark; were in 1798, transported by the French to Paris; and finally, after the overthrow of Buonaparte, and the restoration of the Bourbons in 1815, returned to Venice and placed upon their ancient pedestals. The metal of which these horses had been made was examined by Klaproth, and found by him composed of Copper, 993 Tin, 7 1000 38
Klaproth also analyzed an ancient bronze statue in one of the German cabinets, and found it composed of Copper, 916 Tin, 75 Lead, 97 1000 39
Several other old brass and bronze pieces of metal, very ancient, but found in Germany, were also analyzed by Klaproth. The result of his analyses was as follows:
The metal of which the altar of Krodo was made consisted of Copper, 69 Zinc, 18 Lead, 13 100 40
The emperor’s chair, which had in the eleventh century been transported from Harzburg to Goslar, where it still remains, was found to be composed of Copper, 92·5 Tin, 5·0 Lead, 2·5 100 41
Another piece of metal, which enclosed the high altar in a church in Germany, was composed of Copper, 75·0 Tin, 12·5 Lead, 12·5 100 42
These analyses, though none of them corresponds exactly with the proportions given by Pliny, confirms sufficiently his general statement, that the bronze of the ancients employed for statues was copper, alloyed with lead and tin.
Some of the bronze statues cast by the ancients were of enormous dimensions, and show decisively the great progress which had been made by them in the art of working and casting metals. The addition of the lead and tin would not only add greatly to the hardness of the alloy, but would at the same time render it more easily fusible. The bronze statue of Apollo, placed in the capitol at the time of Pliny, was forty-five feet high, and cost 500 talents, equivalent to about £50,000 of our money. It was brought from Apollonia, in Pontus, by Lucullus. The famous statue of the sun at Rhodes was the work of Chares, a disciple of Lysippus; it was ninety feet high, was twelve years in making, and cost 300 talents (about £30,000). It was made out of the engines of war left by Demetrius when he raised the siege of Rhodes. After standing fifty-six years, it was overthrown by an earthquake. It lay on the ground 900 years, and was sold by Mauvia, king of the Saracens, to a merchant, who loaded 900 camels with the fragments of it.
Copper was introduced into medicine at rather an early period of society, and various medicinal preparations of it are described by Dioscorides and Pliny. It remains for us to notice the most remarkable of these. Pliny mentions an institution, to which he gives the name of Seplasia; the object of which was, to prepare medicines for the use of medical men. It seems, therefore, to have been similar to our apothecaries’ shops of the present day. Pliny reprobates the conduct of the persons who had the charge of these Seplasiæ in his time. They were in the habit of adulterating medicines to such a degree, that nothing good or genuine could be procured from them.43
Both the oxides of copper were known to the ancients, though they were not very accurately distinguished from each other: they were known by the names flos æris and scoria æris, or squama æris. They were obtained by heating bars of copper red-hot and letting them cool, exposed to the air. What fell off during the cooling was the flos, what was driven off by blows of a hammer was the squama or scoria æris. It is obvious, that all these substances were nearly of the same nature, and that they were in reality mixtures of the black and red oxides of copper.
Stomoma seems also to have been an oxide of copper, which was gradually formed upon the surface of the metal, when it was kept in a state of fusion.
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