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BOOK IX
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193
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the
flame comes out and since it has been completely burnt it has the same
lightness as glowing ashes. The foregoing is a description of the cadmia produced from copper ores or from pyrite that contains silver and the plumbum metals. The cadmia found in gold and silver furnaces is usually whiter and lighter since they are cleaned more often.
All cadmia produced
in furnaces dries and is moderately astringent. If it is washed first
it will not cause pain. That obtained from gold, silver, and plumbum ores is less efficacious than that from copper ores.
Pompholyx, after cadmia, adheres to the upper Avails of furnaces and is associated with the latter. It is the ash of either copper or cadmia fornacum or
both. It forms when copper is smelted from cakes of the roasted ores or
when, having been parted from silver, it is refined in a copper
furnace. It is here that the ash is carried to the upper part of the
furnace where it adheres to the walls and back. It first collects in
small balls like drops of water and then swells, whence the name. It
grows by addition of other material until it has the appearance of a
woolen brush. It forms spontaneously in a furnace. When the copper is
smelted from roasted ore the pompholyx is sometimes of a copper
color and when the copper is refined, of a grayish white color, both
being somewhat unctuous. That obtained from the pyrite from Goslar is
white.
By exercising care and diligence furnace workers produce pompholyx from cadmia in three ways. First, by sprinkling cadmia fornacum on copper that is being refined. Pure pompholyx is produced when alternate layers of copper and native cadmia (cadmia fossilis) are
put in retorts to make brass. The ash of the molten copper is carried
up to the hollow in the cover of the retort. If there is no cover on
the retort this ash together with the ash of the burning wood is
carried upward and adheres to the Avails of the furnace producing spodos. A third method is to heat furnace cadmia with
a bellows until it glows. By these methods first quality material is
obtained, that is, the whitest and lightest. Today furnace workers
produce it by another method and at one time it was produced by two
other methods that Dioscorides describes in a manuscript. All three
methods produce a white and light material but the one used today
produces the whitest.
According to Galen the most tenuous portion of pompholyx, after
being washed, is the best remedy known to stop the bite of pain. For
that reason it is used on malignant ulcers and tumors. It is added to
eye salves to stop watering of the eyes and to cure ulcers of the eyes
as well as the pustules the Greeks call φλύκταινα (phyctena). It is also used to cure ulcers of the rectum.
Spodos, that some understand to mean ash, does not differ from pompholyx in origin since both are ashes that are produced in the same way although they are different genera. Pompholyx is white and light, spodos, gray
and heavy. Some of it adheres to the outside of a furnace while some
falls into the lowest part. It is scraped from the walls and swept into
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