Improvements in the Manufacture of Glass Articles in Imitation of Agate.
Year: 1893

page_text: Date of Application, 26th May, 1893-Accepted, 25th Nov., 1893
COMPLETE SPECIFICATION.
Improvements in the Manufacture of Glass Articles in Imitation of
Agate.
I, Count SOLMS-BARUTH, of Klitschdorf, Silesia, in the German Empire, Glass
Manufacturer, do hereby declare the nature of my said invention and in what manner
the same is to be performed, to be particularly described and ascertained in and by
the following statement:-
The object of my invention is to manufacture glass articles in such a manner as
to resemble agate, this object being carried out in the following manner :
1. By introducing in the molten glass, to which coloring metal compounds have
been added, fluxes in large pieces, particularly basalt, which cause a certain amount
of turbidity, and produce effects resembling agate, owing to their incomplete
dissolution, and their irregular dissemination.
2. By adding an excess of these fluxes, which produce turbidity, to the mixed
raw materials used for glass making, and cooling irregularly the outer surface of
the glass when made, whereby dark or deeply colored effects are produced, on a
light ground, upon those parts of the outer surface of the glass which have cooled
more rapidly.
The process is carried out practically in the following manner :—
These ingredients are finely pulverized and intimately mixed, and are placed in a
powdered state in a glass furnace, heated to a very high temperature, that is to
say, are placed in the melting pots of the same.
Instead of basalt, lava or slag from glass or welding furnaces or iron ore or solid
residues of burnt pyrites, may be used.
After the mixture has been thoroughly converted into glass, which is accomplished
after a lapse of about six hours, 20 parts of basalt are gradually introduced in
pieces of the size of a hazel nut, or thereabouts; this last operation taking about
two hours. The whole glass mass is now stirred diligently with an iron bar, while
three parts of dichloride of tin is added to the mixture. After this is done, the
molten glass mass is left for two or three hours, and subjected to the process of
purification, when it is ready for working.
In the working of this glass, it is necessary to produce a cooling as efficient as
possible, not uniformly distributed, but more rapid and extended on parts of the
glass article which it is required to make.
The irregular cooling of the glass may be effected in various ways; one method
consisting in the application of porous wooden moulds, the porosity being so
arranged that some parts may absorb more moisture than others, when water is
applied to the mould.
The irregular cooling may also be effected by blowing the glass in moulds formed
with grooves or corrugations as herein after described.
And in order that my said invention may be more particularly described and
ascertained, reference is hereby made to the accompanying drawings, in which
similar letters of reference indicate corresponding parts.
Fig. 1 is a vertical section of a mould, and Fig. 2 is a top view of the same,
illustrating one method of carrying out my invention.

page_text: a is the mould.
b is a foot or stand. cc vertical grooves formed on the inside of
the mould a. dd are vertical passages for receiving the cooling liquid. e is an
annular passage or groove formed in the upper part of the mould, for distributing
the fluid to the passages dd. The groove e is covered by the annular plate f
is the feeding pipe for the fluid, leading to the groove e.
is the outflow passage
for the fluid.
The cooling fluid enters at 9, passes into the annular groove e, and down the
passages d, d, and out through h. The glass in the mould cools more quickly in
the deepest parts of the grooves c c, and therefore dark shades are in those parts
produced.
Another method of producing irregular cooling consists in forming the walls of
the glass vessels of various thicknesses, whereby the thinner portions cool more
quickly than the thicker parts, and thus produce varied shades of colour.
If instead of adding chloride of silver and dichloride of tin, suboxide of copper
and monoxide of tin are added, a red or black ground color is obtained, according
to the quantity of these fluxes used. By using other coloring fluxes the most
varied ground colors can be obtained.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
1. A process for the manufacture of glass articles resembling agate, characterized
by the introduction, in the molten glass (to which coloring metallic compounds
have been added), of fluxes which produce turbidity such as basalt, in large pieces;
these fluxes owing to their incomplete dissolution and irregular dissemination,
producing effects resembling agate, substantially as described, and illustrated by the
drawings.
2. In the process indicated above, the addition of an excess of the fluxes which
produce turbidity, and especially of basalt, to the glass making material before it
is melted, and the irregular cooling of the manufactured glass, for the purpose of
producing dark or deeply colored designs on a lighter ground, substantially as
described, and illustrated by the drawings.
Dated 26th May 1893.
GEO.
DOWNING,
8, Quality Court, London, W.C., Agent.