Millheim Journal. [volume] (Millheim, Pa.) 1876-1984, 1879-12-11
IrIdescent Glass.

Ii is not generally known, that the beau
tiful 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 Ro-
man days. Most of the old glass brought
to light from the buried cities of Pompeii
and Herculaneum, from Roman tombs, and
more recently from the treasures of the
Cypriote cities or temples, 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
RRffteeh RRfffteeh Afhhae, 6f' 81 Hwhtel6eF ir acquired Tms
quality subsequently by some natural
agency. The more reasonable conclusion,
and the one adapted by Mr.. Peligot, the
celebrated French chemist, is that the glass
originally plain, became iridescent from
long exposure to the action of the air and
moisture at high temperature, these con-
ditIons being admirably fulfilled in the old
Roman tombs, where most OF the glass is
found. all glass has a tendency to be-
come iridescent under certain conditions;
but in some kinds this tendency is more
strongly marked than in others. In glass
for optical instruments tendency ID be-
come iridescent is serious fault and differ-
ent kinds of glass are combined to form a
perfect colorless lens. Modern chemists
and glassmakers have long been trying to
discover the art of making glass iridescent
by some more speedy means than that OF
burying it in damp soil for the benefit of
a thankless posterity. With all the pro-
gress made in kindred branches Of the art,
nothing OF note was done in this direction
until two French chemists quite recently
succeeded in artifcially producing this
lridescence The process they make use
of is said to consist essentially in submitting
the glass, under considerable pressure, and
at an elevated temperature, to the action Of
water containing fifteen per cent. OF hydro
chloric 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
I.dissolving the alkaline silicates and leaving
the surface of the glass finely ridged or cor
rugated, and thus capable of refracting the
lights with prisInatic or rainbow colors, like
those of mother-ot-pearl. The modern glass
stands any amount of rubbing or cleaning
without losing its curious property /; but, if
the exposed surface be cut or ground oil,
the iridescent effect is instantly lost, show
| eAA~N
not structural, as is the case with mother
of pearl. The Bohemian glass, so far, seems
to be the favorite for embellishing with the
new iridescence. Bohemian glass will re-
sist much greater heat than any other
kind, and is made in graceful shapes, and
is clear and transparent. At present the
leading Bohemian factory is producing q
good deal of this iridescent glassware, prin
cipally for the European market, as the
American public is hardly yet acquainted
with this novel and beautiful glassware
One of the greatest charms of this new glas
is its infinite variety and freshness. NJ
two pieces are alike in color, and no piec
remains the same when placed in a new
position or regarded from different poin
of view All show greater or smalle
range of the spectrum, curve or bent, &C
cordipg TO the shape of the glass; but Will
some pieces flash with red and yellow, 9th
4 ers are tender, with silvery blue or ricl
gold gray, and still others exhibit all tn
colors OF the rainbow.