Year: 1877

where to the perfection it has attained
here. This work is often very artistic,
and can only be compared to the art of
engraving on precious stones. The en-
craving is done with copper wheels of
various sizes; upon these the glass is
cut away to a greater or less extent, or
the surface rendered opaque, as the ar
tist may wish. An elaborate pattern
will often require the use of a dozen or
twenty wheels, each of which has its
special work to do.


Glass-cutting is similar to engrav-
ing, being done on a revolving wheel
in the same manner, except that the
wheel is of iron and is used with sand,
which cuts away the surface of the
glass in any form desired. Afterward
the glass is polished on wood and cork
wheels, the finish being given with a
cloth wheel covered with rouge.


The different colors of glass are FORM
ed by the addition of metals, either pure
or in the form of oxides. The rich
rose color is produced by adding Pur-
pie of Cassius, which is largely COM
posed of gold. to the white glass The
blue color comes from cobalt, the yell
low from antimony, or silver, red from
gold, and violet from manganese. Black
glass is formed from mixture of man
ganese, copper, iron and cobalt, and
this composition is largely used in the
manufacture of artificial jet ornaments !;
but much finer quality of black glass,
called Hyalith, is formed by the addi-
tion of sulphur to the crystal glass.
This gives rich black glass that takes
a high polish, is very strong, and can
stand a great amount of heat. This
glass is at present the most fashionable
kind made; il is adapted to any style
of ornamentatiOn, is very durable, and
looks well with almost all surround
ings.


Articles are often formed of two or
more layers of glass, and these may af-
terward be cut away so as to show the
pattern in different colors.


Enameling is now the most popular
decoration for Bohemian glass. Enam-
ell is a glass, made white by adding the
oxide of tin, that melts at a less tenn
perature than the article to which il is
applied The enamel is laid on the
glass. and the piece is put in a muffie
or finishing oven and heated until the
enamel melts and fuses with the glass.
Afterward the enamel may be COlored
with mineral paints in the same way As
in glass painting. Bohemian glass is
especially well suited for this style of
decoration. as il will stand twice the
amount of heat required to weld French
or English crystal. \ very rich effect,
almost equaling in beauty cameO-cut-
ting or pate-sui-pate decoration, which
last it very closely resembles, is produ-
ced by painting figures in pure white
on the black Hyalith glass, the vary
ing thickness of the enamel producing
the richest effects of light and shade.
The pure white enamel is more difficult
toproduce and more artistic in effect
than that which is intended to be col
ored, as the latter is put on of an even
thickness throughout, the effects of
light and shade being added during the
coloring process. The painting of these
pieces is often very artistic; the color
stands out from the body of the ware in
manner unattainable by any other pro-
cess.


The Hyalith glass is sometimes deep
ly engraved in a set pattern, and the
cavities thus formed filled with col
ored paste which melts when the piece
is heated, thus giving a true champlerc
enamel on glass