|
CYANUS.
|
126
|
||
|
|
|||
|
common
method (learnt from the Indians) of forging the transparent precious
stones in the age of Pliny. This mention of Crystal, and the idea
consequently involved of the imitation of a blue, transparent, lustrous
body, though merely based upon a mistranslation, was the sole
foundation for the belief that the Cyanos could be the modern Sapphire,
which the whole tenor of the statement of Theophrastus proves
conclusively it was not.
The
artificial Cyanos is the blue enamel, as our Museums show, used by the
old Egyptians for glazing all their works in terra-cotta, in imitation
of the more sumptuous articles in the then so precious Lapis-lazuli.
Davy found that the Egyptian azure, employed in fresco-painting, could
be exactly and cheaply produced by fusing together during two
hours 15 parts carbonate of soda, 20 powdered flint, and 3 of
copper-filings, yielding thus the true artificial Cyanos of the Greek
mineralogist. The chemist will perceive from its ingredients that this
composition could be applied as an enamel, as well as employed in
powder as a paint ; and that flint replaces the crystal of the old Egyptian recipe.
There can be no doubt that the Cyanos of the earlier Greeks was the mineral known to Pliny as Armenium : both
names being mere epithets, the first denoting its colour (blue), the
second its native country. " Armenia supplies the paint called by its
own name. It is a stone coloured like the Chrysocolla, and" the best
quality, that which approximates nearest to that mineral, yet mixing
its colour with a sky-blue. It is usually priced at 12 denarii per
pound. That found in Spain is in the form of sand, but is prepared for
use in the same manner. The cheapness of the latter brings it down to
6 denarii. It differs from Azure (Caeruleum) by reason of a slight
tinge of whiteness, which renders this colour more tender. Its
|
|||
|
|
|||