IMPROVEMENTS IN COLORED GLASS WINDOWS AND OTHER DECORATIVE GLASS PRODUCTS AND IN METHODS OF MAKING THE SAME
Year: 1883

page_text: PROVISIONAL SPECIFICATION left by Herbert John Allison at the Office of
the Commissioners of Patents on the 4th October 1883. Communicated to
him from abroad by John La Farge, of the City and State of New York,
United States of America, Artist,
HERBERT JOHN ALLISON, of the firm of Allison Brothers, Patent Agents,
Southampton Buildings, London, "IMPROVEMENTS IN COLORED GLASS WINDOWS
AND OTHER DECORATIVE GLASS PRODUCTS AND IN METHODS OF MAKING THE
SAME" a communication to me from abroad by John La Farge, of the City and
State of New York, United States of America, Artist,
The nature of these Improvements consists :-
First. In providing a light metallic frame-work as a substitute for the "leading'
hitherto universally employed for colored glass windows and other decorative glass
products, which while firmly holding the glass segments in position shall present
as thin and light a top or end surface as is consistent with suitable strength, so as
to interfere very slightly, if at all, with the artistic effect of the picture or design
which forms the window or other article; and
"
Second. In combining with the window or other decorative glass product, so
constructed, a thin sheet or film of glass on either the front or back side of the
picture or device, or on both sides of it, for the purpose not only of binding the
segments firmly together and better protecting the glass work from the action of
the atmosphere, but also of rendering the picture homogeneous in all its parts and
thereby greatly enhancing its decorative effect and artistic value.
Prior to my invention, the only mode of constructing colored glass windows and
analogous products has been to employ what are technically termed "" leads" formed
by casting lead into double flanged bars having in cross section substantially the
shape of the letter H laid on its side, and after the colored glass segments or pieces
intended to constitute the picture or device have been cut into the proper shapes,
to bend these leads around the edges of the segments which are fitted into the
space between the flanges, and then at all suitable points where the ends of
different portions of the lead bars come together to solder them in order to hold
the segments in position.
The serious defect in this method is that to give the lead bars sufficient strength
and the flanges sufficient hold upon the glass, it is necessary to make them so wide

page_text: or thick that when the picture or device is looked at they, so too speak, fill too
much of the field of view, and attract the eye too greatly and in obvious ways
seriously impair the artistic effect which the picture would otherwise produce.
It is to do away with this evil that the first part of my improvements is
intended.
To this end, I dispense entirely with the lead bars and flanges, and substitute
for them a light metallic framework made in the form of the design or picture
which the window or other decorative article is to present, and in one form of
framework I secure its connecting parts by soldering or brazing or in any
convenient manner before any portion of the glass segments are placed in position.
By this means the framework is finished complete before the glass is inserted in it.
The segments of differently colored glass are then cut, moulded, pressed, cast or
otherwise formed into the proper shapes to fill the different sections of the frame,
and the various parts or divisions which are to form the finished window or other
article being thus separately prepared, each division-of convenient size-may, if
desired, be placed in the usual manner upon a suitable flat or curved surface so
that the glass segments may be set in position in the sections of the framework in
accordance with the desired picture or design. The workman then sprinkles a
little of any suitable flux in powder, and also, preferably, some powdered white or
colored glass, around the edges of all of the glass segments and into the slight
spaces, if any, which may happen to be left by the workman or may otherwise
occur between the edges of the segments and the framework. In this condition
the work is put into a kiln or any suitable glass furnace and exposed to sufficient
heat therein to fuse the edges of the segments and the powdered glass also
when that is used and unite them securely to and bind them firmly into the
framework.
By this means, I enable the window or other structure, when finished and in
place, to present the picture or device which forms it with the richest effect and
almost entirely free from the disfigurement and artistic embarrassments which
have characterized all previous colored glass decorations of this nature.
Instead of making the framework complete before combining the glass segments
with it, I sometimes prefer to adopt another method. When this is done, the glass
segments may first be cut into the proper shape and size to suit the different parts
of the design, and the workman then places them on a suitable flat surface and
taking a plain flat strip of the thin metal which is to constitute the framework,
bends it around the edges of the segments, holding the segments and the bent
portions of the metallic strip or strips in position meanwhile by suitable pins or
nails, and solders or brazes the ends of the strips where they come together. In
this way, the framework is made as the work progresses. By means of it, con-
siderable time may often be saved, and the segments are not required to be cut
with so much exactness as when the first form of framework described is employed,
since if they chance to vary somewhat from the desired dimensions the flat strips
can be bent to them before being soldered.
To enhance the artistic results of the work, I usually prefer to combine with the
segments and frame a thin sheet or film of white or colored glass, placed on both
sides of the picture or on only one, as may be desired. These sheets of glass may
advantageously be about one thirty-second of an inch or somewhat more in
thickness, and they are laid upon the upper and under surfaces or upon either the
upper or under surface--as the case may be of the framework and segments when
the latter with the plaster or other suitable base on which they customarily rest in
the course of manufacture are put into the kiln or furnace as before described, and
while the edges of the segments are being fused the glass films will become partially
melted and will not only bind the segments and framework firmly together but will
also, when the work is done properly, cover both segments and framework with a
thin, level, smooth film or surface of glass which will tend materially to harmonize
the different portions of the window or other structure and blend them into a
homogeneous and artistic picture.

page_text: Besides these advantages, the employment of the glass films will protect the
work from the effects of the weather and atmospheric changes when it is placed in
an exposed situation, as will often be the case.
In addition to the superior decorative effects of my improvements, they enable
work of a high grade, which has hitherto been extremely costly, to be produced by
less skilful workmen and in far less time than has before been possible, and hence
greatly diminishes its cost.