AN IMPROVED PROCESS OF APPLYING METALS IN THE MANUFACTURE OF GLASSWARE FOR THE PRODUCTION OF A CERTAIN ORNAMENTAL EFFECT THEREON
Year: 1878

page_text: LETTERS PATENT to Alexander Melville Clark, of Chancery Lane, in the
County of Middlesex, Patent Agent, for the Invention of "AN IMPROVED
PROCESS OF APPLYING METALS IN THE MANUFACTURE OF GLASSWARE FOR THE
PRODUCTION OF A CERTAIN ORNAMENTAL EFFECT THEREON." A communica-
tion from abroad by Messieurs Monot, père et fils, and Stumpf, of Paris,
France
Sealed the 20th May 1879, and dated the 29th November 1878.
PROVISIONAL SPECIFICATION left by the said Alexander Melville Clark at
the Office of the Commissioners of Patents on the 29th November 1878.
ALEXANDER MELVILLE CLARK, of Chancery Lane, in the County of Middlesex,
Patent Agent.
"AN IMPROVED PROCESS OF APPLYING METALS IN THE MANUFAC-
TURE OF GLASSWARE FOR THE PRODUCTION OF A CERTAIN ORNAMENTAL EFFECT
THEREON." [A communication from abroad by Messieurs Monot, père et fils, and
Stumpf, of Paris, France.]
"
This Invention relates to a process of applying a layer of gold or other metal
either between two layers or thicknesses of glass or crystal, or on the exterior
thereof, for the purpose of producing the ornamental effect known in France as
chiné metallique."
The only methods hitherto used for obtaining this effect (which is produced by
disseminated particles of metal), whether externally on articles of glass, or internally,
i.e., imprisoned between two layers or thickness of glass, were as follows:-To take
the latter mode of application first, it has always been necessary to employ two
articles of glass of the same form, but the one slightly sinaller than the other, so
that it can be introduced or fitted therein, and the two be welded together. Thus,
for example, two tubes have been used, the one arranged to fit into the other; on
the external surface of the smaller tube a sheet of gold or silver or other foil or leaf
was applied, or it was coated with a metallic solution; the two tubes were then
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page_text: heated, and placed the one in the other; the outer tube was then closed at one end,
and, by blowing, the inner tube was expanded and made to fit and adhere closely
to the outer tube; the gold or other foil or leaf was thus imprisoned between the
two tubes. To produce the ornamental effect desired the tubes were reheated, and
then blown, so as to expand the tubes until the imprisoned layer or leaf is burst or
torn in all directions, thus producing the ornamental effect desired.
Or the same result (the metal leaf being imprisoned between two layers of glass,
as before) has been obtained in another way; the glass was taken from the glass
pot, and rolled on a marver to form a solid rod or cylinder, on which marver has
been previously laid a gold or other leaf or a layer of metallic powder which will
adhere to the cylinder or rod of glass which was then introduced into a rather
larger tube or hollow cylinder of glass, and the two together taken to the furnace
and then blown, to tear and subdivide the metal and produce the effect desired, and
afterwards finished.
To produce the ornamental effect on the exterior of objects or articles of glass
the cylinder of glass (tubular or solid, as the case may be) was coated with leaf or
powder by one of the ways above described, but instead of being then placed in an
outer tube of glass, it was carried to the furnace and blown, to bring it to the
desired shape and produce the ornamental effect desired. Instead of sprinkling
metallic powder on a slab, and rolling the glass upon it, the powder contained
in a sieve was sprinkled directly on the glass.
All these processes are tedious, and more or less impracticable.
In the first place, the wrapping of the leaf round the glass tube, whether hot or
cold, requires very great care, and the end or edge of the leaf always forms upon
the glass a line or streak, which is a blemish which shows when the article is
finished. Secondly, the processes render the manufacture very slow, as in intro-
ducing the one tube or cylinder in the other the metallic layer is liable to be
chafed and torn, thereby destroying the uniformity of distribution of the metal;
then it is necessary to heat the two tubes, blow them so as to weld them together,
reheat them with great precautions, so that the air between them shall not be
imprisoned when the two are welded together; all these accidents the most expert
glass worker has much difficulty to avoid. The process is moreover limited to
articles of small dimensions, and thus, owing to the length of time and labor it
involves, its complexity and difficulty, it is practically of little use.
All these
difficulties and objections are avoided by the process or means of this Invention,
which is characterised by the novel application of a sort of flared cap, crown, or
envelope of glass, termed by glass workers in France a chemise, for the production
of the above ornamental effects, whether on the exterior or on the interior of crystal
or glass ware, or in the midst or body even of the glass itself.
To produce the ornamental effect desired between two layers or thicknesses of
glass I proceed as follows:-I apply a metallic coat or layer to the internal surface
of the cap or envelope, either in the form of a metallic solution or otherwise, as
found convenient, and I then take from the glass pot glass, which I place in the
said cup or envelope, and then by simple pressure by the aid of the blowing
iron, the glass being soft, adheres and becomes welded to the cap or envelope, the
metallic layer being thus imprisoned between two layers or thicknesses of glass,
which is then carried to the furnace, blown, moulded, and the article finished. By
blowing, the glass is expanded or dilated to an extent to which the metal cannot
conform, and the latter is therefore no longer a continuous layer, but is burst or
torn into particles or spangles, which are disseminated in the thickness of the
article, which thus acquires the ornamental aspect desired. Or the metallic coat or
layer may be applied on the external instead of on the internal surface of the cap
or envelope, and glass taken from the pot be placed and merely pressed therein, as
before, by means of the blow pipe, to make it adhere or weld itself thereto; the
whole is then dipped in the pot, and thus the metal coating is imprisoned between
two layers of glass, and the whole blown, to produce the effect desired, and moulded

page_text: and finished. If it is desired, the metal should remain at the external surface of the
article, instead of dipping it in the pot as last mentioned, it is carried to the furnace,
blown to tear or disseminate the metal, moulded, and finished.
By the above means uniformity in the distribution of the metal is obtained,
which is not liable to be destroyed by the subsequent operations; air bubbles are
avoided; the union of the two layers which imprison the metal does not necessitate
that they should be previously adjusted approximately the one to the other, as it is
effected by the simple introduction of a mass of glass of any form into the glass cap,
crown, or envelope, and the mere pressure on this mass, neither of which operations
require particular attention on the part of the glass worker. Lastly, the use of the
cap, crown, or envelope has this advantage over the use of tubes or cylinders, that
with the latter there is a great difficulty in making articles of a certain size,
whereas with the former, articles both large and small may be made with equal
facility.
The articles thus manufactured may be still further enriched or ornamented by
any known means. Thus the internal surface may be metallized and the external
surface craquelled or ornamented in any suitable way.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Alexander Melville Clark in the Great Seal Patent Office on the
29th May 1879.
cr
ALEXANDER MELVILLE CLARK, of Chancery Lane, in the County of Middlesex,
Patent Agent. "AN IMPROVED PROCESS OF APPLYING METALS IN THE MANUFAC-
TURE OF GLASSWARE FOR THE PRODUCTION OF A CERTAIN ORNAMENTAL EFFECT
THEREON. A communication from abroad by Messieurs Monot, père et fils, and
Stumpf, of Paris, France.
This Invention relates to a process of applying a layer of gold or other leaf either
between two layers or thicknesses of crystal or other glass, or upon the exterior
thereof, to form the spangles or disseminated particles of metal producing the
ornamental effect known in France as "chiné metallique genre Corinthien" (from
its resemblance to the spangled enamels found at Corinth), and which somewhat
resembles aventurine glass. The only methods hitherto used for obtaining this
effect, whether externally or internally (i.e., imprisoned between two layers of glass),
were as follows:-
To interpose a layer of metal between two layers of glass it has been necessary
to employ two articles of glass of the same form but of different sizes, so as to fit
the one in the other for the purpose of being welded together.
For example, two glass tubes have been so used, the external surface of the smaller
tube being first coated with gold or silver leaf or with a metallic solution; the two
tubes were then heated, and placed the one in the other, the outer tube then being
closed at one end and the inner tube expanded by blowing, and made to fit and
adhere closely to the outer tube so that the gold or other leaf was thus imprisoned
between the two tubes.
To produce the ornamental effect above referred to the tubes were then heated in
the furnace, blown, and expanded until the imprisoned metallic layer was burst or
torn in all directions. The same result has also been obtained in another way, viz.,
the glass was taken from the glass pot and formed into a solid rod or cylinder by
rolling on a marver on which has been previously laid a gold or other leaf or a
layer of metallic powder, which was thus caused to adhere to the cylinder or rod of
glass. The latter was then introduced into a rather larger tube or hollow cylinder
of glass, and the two together taken to the furnace and there blown to tear or
disseminate the metal and produce the effect desired, after which the proper form
was given to the work, and the article finished in the ordinary way.
To produce the ornamental effect on the exterior of articles of glass the cylinder
of glass (tubular or solid, as the case may be,) was coated with metallic leaf or
powder by one of the ways above described, or by sprinkling the powder contained
in a sieve directly on the glass while on the blowing iron, but instead of being then
placed in an outer tube of glass it was carried to the furnace and blown, to give the
article the desired shape and produce the ornamental effect, and afterwards finished
in the usual way.
All these processes are tedious, and more or less impracticable. In the first place,
the wrapping of the leaf round the glass tube, whether hot or cold, requires very
great care, and the edge of the leaf always produces upon the glass a line or streak
which forms a blemish in the finished article. Secondly, the processes are very
slow, because in introducing the one tube or cylinder into the other the metallic
layer is liable to be chafed and torn, thereby destroying the uniformity of the
distribution of the metal; then it is necessary to heat the two tubes, blow them so
as to weld them together, and reheat them with great precautions, so that the air
between them shall not be imprisoned when the two are welded together. All these

page_text: accidents the most expert glass worker has much difficulty to avoid, and even
then he is limited by practical considerations to the production of articles of small
or moderate dimensions. This fact, coupled with the amount of labor they
involve, render these processes of little practical use. All these objections are
avoided by the process of this Invention, which consists in the employment of a
bowl shaped shell or "casing" as used in making cased glass, and in the application
therein or thereon, first, of the metallic layer, and, secondly, of a mass of plastic glass
which unites with the casing, the two being then blown together to produce the
said ornamental effect and form the article desired.
To produce the said ornamental effect between two layers or thicknesses of glass,
I proceed as follows:-A casing is made in the ordinary way by blowing a bulb of
glass whilst its lower part rests in a mould of the form of the end of an egg, and
then severing the glass just above the mould, leaving the lower part of the bulb,
which forms the "casing," in the mould, where it is allowed to cool. When cold it
is removed and coated internally in any suitable way with a layer of gold, silver, or
other metallic leaf, or with a metallic solution (nitrate of silver or chloride of gold,
for instance). The casing is then replaced in the mould, and I then take glass from
the pot on the end of the blowing iron, blow it to a small bulb, and press it in the
casing with the aid of the blowing iron until the plastic glass adheres or becomes
welded to the "casing," without leaving any air space between the two. The
metallic layer being thus imprisoned between two layers of glass, the whole is then
removed from the mould and carried to the furnace, blown, and moulded to the form
of the article desired, which is afterwards finished in the usual way. By blowing,
the bulb of glass and its enveloping casing become expanded to such an extent as
to burst or tear the metallic layer into particles or spangles, which are thus dissemi-
nated in the body of the glass, imparting to the article the decorative effect herein
designated "chiné metallique genre Corinthien." Or the metallic coating or layer
may be applied upon the external instead of on the internal surface of the "casing,"
and glass taken from the pot be introduced and merely pressed therein, as before,
by means of the blowing iron, to make it adhere or weld itself thereto, the whole
being then dipped in the pot. The metal coating is thus imprisoned between two
layers of glass, which is then blown to produce the spangled effect desired, moulded,
and finished. If it is desired that the metallic ornamentation should remain upon
the external surface of the article the metal is applied upon the outside of the
casing," into which glass is then introduced from the pot, and by pressure caused
to adhere or be welded to the "casing." The glass is then carried to the furnace,
blown to tear or disseminate the metal, moulded, and finished.
"
"
By the above means uniformity in the distribution of the metal is obtained,
which is not liable to be destroyed by the subsequent operations; air bubbles are
avoided, and the union of the two layers which imprison the metal does not neces-
sitate that they should be previously adjusted approximately the one to the other,
as it is effected by simply introducing a mass of soft glass of any form into the
casing" (to the shape of which the plastic glass readily conforins), and merely
pressing on this mass, neither of which operations requires particular care on the
part of the glass worker. Lastly, the use of the "casing". has this advantage over
the use of tubes or cylinders, that with the latter there is a great difficulty in
making articles beyond a certain size, whereas with the former articles both large
and small may be made with equal facility.
The articles thus manufactured may be still further enriched or ornamented.
Thus the internal surface may be metallized and the external surface "crackled "
by the methods described in the Specifications of Letters Patent of even date here-
with, Nos. 4880 and 4881.
Having described the nature of the Invention and the manner of performing
the same,
I declare that what I claim as the Invention to be protected by the
hereinbefore in part recited Letters Patent is,-

page_text: The process or method of producing in the manufacture of articles of glass the
ornamental effect herein specified, which process consists in the employment of a
bowl shaped shell of glass termed a "casing," to the inside or outside of which a
metallic layer is first applied, and in or on which a mass of soft glass is then applied,
the two being afterwards blown together to form the article and produce the chiné
metallique effect, substantially as herein described.
In witness whereof, I, the said Alexander Melville Clark, have hereunto set
my hand and seal, this Twenty-ninth day of May, in the year of our Lord
One thousand eight hundred and seventy nine.