IMPROVEMENTS IN THE PROCESS OF SILVERING GLASS BY PRECIPITATION OF SILVER
Year: 1882

page_text: LETTERS PATENT to James Edmondson Pratt of Clifton Lodge Flodden Road
Camberwell Surrey for an Invention of "IMPROVEMENTS IN THE PROCESS
OF SILVERING GLASS BY PRECIPITATION OF SILVER"
PROVISIONAL SPECIFICATION left by the said James Edmondson Pratt
at the Office of the Commissioners of Patents on the 2nd February 1882.
JAMES EDMONDSON PRATT of Clifton Lodge Flodden Road Camberwell Surrey
"IMPROVEMENTS IN THE PROCESS OF SILVERING GLASS BY PRECIPITATION OF
SILVER"
This Invention of improvements in the process of silvering glass by precipitation
of silver relates to the manipulation and management of the process and the manner
of supporting the glass to be silvered, the ordinary solutions known to glass silverers
being employed.
The success of the process depends as is well known upon obtaining a regular
deposit over every part of the glass and the method of doing this at present is to
have a large and perfectly level table upon which the glass to be silvered is placed,
round the edge of the glass are placed battens of wood or other material to confino
the liquid to be used whilst the silver in it is being deposited upon the plate, of a
certain required depth and equal in depth all over the plate, so important is this
that means are used to ease up by wedges any hollow part of the glass lying on the
table.
A Patent was only taken by myself in 1876 N° 1258 in which this table was
supported on a frame with trunnions on a suitable stand so that the liquid could be
rocked to and fro, such manipulation of the plate and the expense of such frames
and stand are however very costly.
I have discovered that a much better deposit can be made and much more quickly
and with very greatly increased economy in the manual labour by the following
method.
I make a fixed incline of about 1 inch in a foot inclination which is covered with
the usual covering, upon this incline I place the glass or glasses to be silvered, the

page_text: sides of the inclined bed are raised to prevent waste of liquid, at the bottom of the
incline is a trough with an inclination to one of the lower corners of the incline so
that the liquid escaping over or running down the incline can be brought to this
corner or nearly so and a small outlet in the trough will conduct the liquid into a
jug or vessel placed there to receive it.
The inclined bed is heated by steam or other suitable means and the glasses or
glass to be silvered being placed upon the inclined table the workman takes a jug
of the prepared liquid and rapidly pours it over the top edge of the glass plate or
if there are two or more plates upon the highest portion of the highest plate or in
the middle the object being to cover all parts of the plate as quickly as possible.
As the liquid escapes by the outlet described it is caught in the jug or vessel which
is then taken by the workman and replaced by the now empty jug or vessel first
used and so alternately. In this way an almost constant stream of liquid is flowing
over the surface of the glass plate or plates and the deposit of silver takes place
quickly and evenly.
There are very great economies resulting from this Invention-Firstly-In the
quantity of solution used. Secondly-In the evenly distributed film of silver-
Thirdly In the saving of manual labour employed and Fourthly-In the saving
of time, a few minutes sufficing to complete a very large plate.
It will be seen that the principle of success in this Invention depends upon the
fact of giving the plate such an inclination that the solution Bows over rapidly and
being caught and repoured over the plate, the deposit forms quickly evenly and
with little labour. It is evident that these conditions could bo secured by the
glass being held (at the required inclination) or suspended in a frame means being
taken to prevent the liquid escaping over the sides and the under side of the glass
could be warmed by steam or warin air or water by jets or otherwise but in the
description given I have described the best means I am acquainted with for the
purpose.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said James Edmondson Pratt in the Great Seal Patent Office on tho
2nd August 1882.
JAMES EDMONDSON PRATT of Clifton Lodge Flodden Road Camberwell Surrey
"IMPROVEMENTS IN THE PROCESS OF SILVERING GLASS BY PRECIPITATION OF
SILVER."
This Invention of improvements in the process of silvering glass by precipitation
of silver relates to the manipulation and management of the process and the manner
of supporting the glass to be silvered, the ordinary solutions known to glass silverers
being employed.
The success of the process depends as is well known upon obtaining a regular
deposit over every part of the glass and the method of doing this at present is to
have a large and perfectly level tablo upon which the glass to be silvered is placed,
round the edges of the glass are placed batteries of wood or other material to
confine the liquid to be used; whilst the silver in it is being deposited upon the plate;
of a certain required depth and equal in depth all over the plate so important is
this that means are used to case up by wedges any hollow part of the glass lying
on the table.
A Patent was also taken by myself in 1870 N° 1258 in which this table was
supported on a frame with trunnions on a suitable stand so that the liquid could be
rocked to and fro such manipulation of the plate and the expense of such frames
and stand are however very costly.
I have discovered that a much better deposit can be made and much more quickly
and with very greatly increased economy in the manual labour by the following
method.
I make a fixed incline of about 1 inch in a foot inclination which I find very
suitable though a greater incline may be used or even a less one the incline is
covered with the usual covering, upon this incline I place the glass or glasses to be
silvered the sides of the inclined bed are raised to prevent waste of liquid, at the
bottom of the incline is a trough with an inclination to one of the lower corners of
the incline so that the liquid escaping over or running down the incline can be
brought to this corner or nearly so and a small outlet in the trough will conduct
the liquid into a jug or vessel placed there to receive it the inclined bed is covered
with the ordinary and various coverings used by glass silverers.
The inclined bed is heated by steam or other suitable means and the glasses or
glass to be silvered being placed upon the inclined table the workman takes a jug
of the prepared liquid and rapidly pours it over the top edge of the glass plate or
if there are two or more plates upon the highest portion of the highest plate or in
the middle the object being to cover all parts of the plate as quickly as possible.
As the liquid escapes by the outlet described it is caught in the jug or vessel which
is then taken by the workman and replaced by the now empty jug or vessel first
used and so alternately. In this way an almost constant stream of liquid is flowing
over the surface of the glass plate or plates and the deposit of silver takes place
quickly and evenly.
There are very great economies resulting from this Invention. First in the
quantity of solution used for covering the plates. Secondly In the more evenly
distributed film of silver and in tho greater solidity and firmness of the deposit.
Thirdly In the saving of manual labour employed, and Fourthly In the saving of
time; a few minutes sufficing to complete a very large plate.

page_text: It will be seen that the principle of success in this Invention depends upon the
fact of giving the plate such an inclination that the solution flows over rapidly and
can be caught quickly and repoured over the plate the deposit forms quickly evenly
and with little labour; it is evident that these conditions could be secured by the
glass being held at the required inclination or suspended in a frame means being
taken to prevent the liquid escaping over the sides and the under side of the glass
could be warmed by steam or warm air or water, by jets or otherwise but in the
description given I have described the best means I am acquainted with for tho
purpose of carrying out my Invention.
Having now described and particularly set forth the nature of the said Invention
and the manner of carrying the same into effect I would have it understood that
what I claim is:-
The use of an inclined and fixed table heated and covered in any suitable
way for the purpose of silvering glass plates in the manner substantially as
described.
In witness whereof I the said James Edmondson Pratt have hereunto set
my hand and seal this Thirty first day of July in the year of our Lord
One thousand eight hundred and eighty two.