The Democratic press. [volume] (Ravenna, O. [Ohio]) 1868-1901, 1879-12-11
lR1DEscENr GLASS.
The Revival of One of the LO
Arts OF Old lS oman Days.

1ne h0V1Val Oh one OF tine Lost
Arts OF Old Roman Days.
1t is not generally known, says the
Boston Commercial Bulletin, that the
beautiful vases, and other forms Of
iridescent glass, which have recently
begun to adorn the windows of our
chinaware dealers, mark the revival
of one of the lost arts of old Roman
days. Most of the old lglass brought
to light from the buried cities of Pom
peii and Herculaneum, from Roman
tombs, and more recently from the
treasures of the Cypriotic cities or
temple, possesses this curious property
of iridescence, by means of which it
reflects light with all the colors of the
rainbow. There has been some dis
pute as to whether this glass was ir-
idescent when made, or whether it
acquired this quality subsequently by
some natural agency. The more rea-
sonable conclusion, and the one adopt
ed by Mr.. Peligot, the celebrated
French chemist, is that the glass, Or
iginally plain, became iridescent
from long exposure to the action of
the air and moisture at high rate of
temperature, these conditions being
admirably fulfilled in the old Roman
toombs, where most of this glass is
found. ALI glass has q tendency to
become iridescent under certain con-
ditions; but in some kinds this tend
ency is more strongly marked than in
others. In glass for optical instru-
ments tendency to become rides
cent is q serious fault, and different
kinds of glass are combined to form a
perfectly c0lorless lens. Modern
chemists and glass makers have long
been trying to discover the art of
making glass iridescent by some more
speedy means than that of buryipg it
in damp soil for the benefit of thank
less posterity. With all the progress
made in kindred branches of the art,
nothing of note was done in this di-
rection until two French chemists
quite recently succeeded in artificially
producing iridescence. The process
they make use of is said to con-
sist essentially in submitting the glass
under a considerable pressure, and an
temperature, to the action of
water containing Is per cent. of hy-
acid. Only certain kinds
of glass are suitable for this operation.
The action of this acid is thought to be
analogous to that of the elements upon
the older glass in dissolving the aka
line silicates and leaving the surface of
the glass finely ridged or corrugated.
and thus capable of refracting the
lights with prismatic or rainbow COL
ors, like those of mother of-pearl.
The modern glass stands any amount
of rubbing or cleaning without losing
its curious property; but if the ex-
posed surface be cut or ground off,
the iridescent effect is instantly losts
showing that its cause is merely su-
perficial and not structural, AS is the
case with mother-of-pearl. The Boz
hemian glass, so far, seems to be the
faYorite for embellishing with the
new iridescence. At present the lead
ing Bohemian factory is producing q
good deal of this iridescent glassware,
principally for the European market,
as the American public is hardly yet
acquainted with this novel and beau
tiful glassware.
One of the greatest charms of this
glass is its infinite variety and fresh
ness. No two pieces are alike in color
and no piece remains the same when.
placed In a new position or regarded
from different point of view. All
show greater or smaller range of the
spectrum, curve or bent, according to
The shape of the glass but while some
pieces fash with red and yellow, 9TH
srs are tender with the silvery blue or
-ich gold gray, and still others exhibit
I'll the colors of the rainbow,