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Book IX artificially coloring of metals such as gold, silver, copper

Book IX artificially coloring of metals such as gold, silver, copper Page of 251 Book IX artificially coloring of metals such as gold, silver, copper Text size:minus plus Restore normal size   Mail page  Print this page
194
DE NATURA FOSSILIUM
piles. It is not obtained from furnaces in which they smelt copper ores, copper, cadmia, or pyrite. It is produced in furnaces in which they smelt gold, silver, and lead ores and here it forms instead of pompholyx. In these furnaces the material is gray while that obtained from furnaces in which silver is parted from lead is yellow. Part of the lead is consumed in the fire and carried upward with the smoke and this produces spodos.
Dioscorides mentions plumbaria from the Cyprian copper smelters. Pliny writes that similar material from gold smelters is very good for the eyes and that the product from silver smelters is called lauriotis. This evidently takes its name from Mt. Laurium in Greece where there are silver mines. After the Athenians abandoned these mines the name con­tinued to be used for spodos from silver smelters. All spodos when cleansed of filth such as carbon, earth, hair, dirt, etc. has the same properties as pompholyx. As a rule it is, in part at least, coarser grained or more dense.
Flowers of copper (flos aeris), also called άνθος χαλκός by the Greeks, consists of small particles of copper that have been loosened from the main mass and have, in general, the appearance of millet. It is produced in two ways, one when the copper has been refined from roasted ore and flows from the hearth along canals into the crucible. It is also obtained when copper that has had the lead and silver removed is melted in the crucible of a single hearth. With either method, after the slag has been removed from the mass of glowing copper the latter is poured into water immediately so that it can be divided into bars. The copper, since it con­geals and hardens quickly, spurts out into a flower. These flowers are cut from the bars by a helper with a pair of pinchers and thrown into a basin or trough to quench them. After pouring the water from the basin they are collected. The best of these can be ground easily and when ground have a red color. They have a moderate luster. This material is adulter­ated with copper filings but the fraud can be detected by biting since the copper filings will spread under pressure. Flowers of copper can be dis­tinguished from the scale the Greeks call Xeiros since the former is produced spontaneously from copper bars that are chilled in water while the latter is torn from masses of copper by the blows of a hammer, from nails and then called ήλϊτκ, and from other copper objects. The best material is dense and copper-red. When sprinkled with acid it produces verdigris, the same kind as is now scraped from red copper and at one time was made from Cyprian copper. On the other hand tenuous, crumbling, white or black material is discarded. This is produced from white or black copper. Both flowers of copper and copper scale have the same properties as roasted copper, that is, a certain acridness except that it is astringent. Flowers of copper is more tenuous than either scale or roasted copper and for that reason is mixed with eye remedies to cure irritations and ulcers. When the scale is drunk with honey and water it draws water from the body.
Scale {squama) is broken from the hard iron the Greeks call στομωμα,
Book IX artificially coloring of metals such as gold, silver, copper Page of 251 Book IX artificially coloring of metals such as gold, silver, copper
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