IMPROVEMENTS IN THE APPARATUS USED IN SILVERING LOOKING-GLASSES OF ALL SIZES
Year: 1869

page_text: LETTERS PATENT to Claude Adolphe Maugin, of No. 58, Boulevart
Richard Lenoir, in the City of Paris, in the Empire of France,
Looking-glass Maker, for the Invention of "IMPROVEMENTS IN THE
APPARATUS USED IN SILVERING LOOKING-GLASSES OF ALL SIZES."
Sealed the 29th March 1870, and dated the 2nd October 1869.
PROVISIONAL SPECIFICATION left by the said Claude Adolphe Maugin
at the Office of the Commissioners of Patents, with his Petition,
on the 2nd October 1869.
I, CLAUDE ADOLPHE MAUGIN, of No. 53, Boulevart Richard Lenoir,
in the City of Paris, in the Empire of France, Looking-glass Maker,.
do hereby declare the nature of the said Invention of "IMPROVEMENTS.
IN THE APPARATUS USED IN SILVERING LOOKING-GLASSES OF ALL SIZES," to be as.
follows:-
This Invention relates to silvering tables, the principal features of
which are that the surface is provided with a number of holes so
that the steam with which they are heated internally may escape,
and reaching the cotton cover placed above on which the glass to be

page_text: silvered is placed keeps it damp and thus prevents its being dried up or
burned, and by preventing the boiling of the silvering liquid preserves
the glass from breakage. These tables are made of sheet or cast iron,
zinc, earthenware, or any other hard substance the surface of which is
perfectly smooth and horizontal. Round the sides of this are trenches!
or gutters filled with water, in which the ends of the cover bathe, so as
to keep the surface level and to receive any particles of the silvery
liquid which may escape whilst casting or feeding its ends.
And in order to prevent the least flexion in any part the table is cross
quartered with angle irons and is supported by columns or pedestals. I
The gutters are cleared by means of two pipes, each of which clears two
gutters and are furnished with taps emptying themselves in troughs
made in the stone or brickwork of the base.
The condensed or other steam remaining in the interior after the
silvering is completed is expelled by aid of a blow-off cock. By this 1
system there is a great saving of steam and fuel, together with a perfect
security against breaking the glass which is of frequent occurrence with
the old method where the steam heats, the interior of the table only.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Claude Adolphe Maugin in the Great Seal Patent
Office on the 1st April 1870.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, CLAUDE
ADOLPHE MAUGIN, of No. 53, Boulevard Richard Lenoir, in the City
of Paris, in the Empire of France, Looking-glass Maker, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Second day of October, in the year of
our Lord One thousand eight hundred and sixty-nine, in the thirty-third
year of Her reign, did, for. Herself, Her heirs and successors, give
and grant unto me, the said Claude Adolphe Maugin, Her special.
licence that I, the said Claude Adolphe Maugin, my executors, adminis-
trators, and assigns, or such others as I, the said Claude Adolphe Maugin,
my executors, administrators, and assigns, should at any time agree
with, and no others, from time to time and at all times thereafter
during the term therein expressed, should and lawfully might make,
'use, exercise, and vend, within the United Kingdom of Great Britain

page_text: and Ireland, the Channel Islands, and Isle of Man, an Invention for
"IMPROVEMENTS IN THE APPARATUS USED IN SILVERING LOOKING-GLASSES OF ALL
SIXES," upon the condition (amongst others) that I, the said Claude
Adolphe Maugin, my executors or administrators, by an instrument in
writing under my, or their, or one of their hands and seals, should par-
ticularly describe and ascertain the nature of the said Invention, and in
what manner the same was to be performed, and cause the same to be
filed in the Great Seal Patent Office within six calendar months next
and immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Claude Adolphe Maugin, 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 thereof, reference being had to the Drawings
hereunto annexed, that is to say :-
For many years it has been the custom to make use for the quick-
silvering of looking-glasses and mirrors of silvering tables constructed
of cast iron with a smooth surface and of a length varying from about
10 feet, a breadth of 6%, feet, and a thickness of 6 inches. These tables
are very costly and weighty. Upon them a linen covering which has
been previously moistened is spread and they are heated by a current
of steam. The glass is laid upon the moistened covering, and upon the
surface of the latter as much of the argentiferous fluid is poured as
capillary attraction will retain. The table being very level the glass is
left upon it for about 20 minutes which is the time necessary to allow
the metallisation which takes place upon the decomposition of the argen-
tiferous solution, which precipitates the silver in the metallic state upon
the glass in consequence of the action of a reducing salt and of
ammonia in a quantity equivalent to the solution of nitrate of silver
dissolved in distilled water. After the mixture of these solutions a little
heat must be applied which is produced by a current of steam in order
to produce the deposit of silver. It is unnecessary to give the exact
formula of the argentiferous solution, as there are several processes for
obtaining it which are well known.
The object of the present Invention is to improve the silvering tables
above mentioned so as both to economise the steam and fuel as well as to
prevent the frequent breaking of the glasses which occurs in the present
apparatus, in which the steam only warms the interior of the table and
the covering is soon dried and burned for want of water, whilst according

page_text: to my system the steam which proceeds through little holes or other
orifices and keeps up the dampness of the cotton covering entirely
obviates these inconveniences. The edges of the covering dip into
reservoir troughs filled with water and by capillay attraction supplies
itself with water enough to keep up its humidity as the heat withdraws
it. I make these tables of sheet or plate iron or other convenient metal
of 10th of an inch (3 millimetres) in thickness and well beaten by
the hammer and planed. The tables not only act regularly and prevent
the burning of their coverings, but they also effect an enormous economy
over those at present in use and weigh only one-tenth as much. I am
also enabled to accomplish the silvering of glasses by their means in ten
minutes which in all other methods takes double the time.
The Drawings annexed to this description will enable the advantages
of my system to be readily understood.
Figure 1 shows one of my improved tables partly in section and
partly in elevation. Figure 2 is a plan, part of which is in section in
order to show the interior of the apparatus. The table is composed of
a prism of sheet iron or other convenient metal, the upper face a of
which is perfectly smooth and horizontal. Upon this face a which is
perforated either by means of cylindrical holes b, b, b, b, or other
openings of any desired figure, the cotton covering is placed, and upon
this covering the glass to be silvered is laid. At one of the extremities
of the perforated surface of the table a small tube n is placed, through
which steam proceeds slowly in order to prevent any movement of the
covering with the glass upon it at the moment of the introduction of
steam upon the table. The table is conveniently cross quartered or
tied by iron pieces c, angle irons, or other similar means, so as to prevent
any flexion. It is supported by columns or pedestals d, d, variable in
number, and has upon each of its four sides double trenches or
gutters g, 9, 9, 9', the first of which are intended to receive any particles
of the silvering liquid which may escape when it is spread over the glass.
The second ones g³, 9', are filled with water in order to supply the.
capillary attraction. The trenches g', g', are provided with emptying
pipes ff, each serving for two trenches conveniently inclined, as shewn
in Figures 2 and 4 of the Drawings. To each of these pipes cocks are
adapted which it is easy to open and close. The pipes ff, lead into
one of the troughs h, h, placed upon the supporting stone or into any
other convenient receptacle. I said when stating my system that its

page_text: principle was to heat the surface which receives the glasses by means
of a jet of steam. The pipe & with its cock is intended to conduct from
the generator into the interior of the table the steam for heating the
upper surface. It will be understood that this steam has a double object;
to heat the upper surface a and passing through the holes b, b, b, b, to
condense upon the covering and become imbibed by it, and by pre-
venting the silvering liquid from boiling to avoid the breakage of the
glasses thus prepared. The pipe k is perforated and branches into the
interior of the table. The steam whether condensed or not which is
in the interior of the table after the silvering will be returned to the
exterior by the emptying cock m. I can, when necessary, instead of per-
forating the face a of the table dispose upon its surface an indeterminate
number of tubes, the object of which would be to produce identically
the same result as the holes b, b, b, b.
Figures 3 and 4 show in elevation, section, and plan another arrange-
ment which I may sometimes employ. It is composed of a prismatic
table with a plane or horizontal surface a, but differing from the table
shewn in Figures 1 and 2; in that this surface a instead of being
perforated is full. The table supported by columns d, d, is provided
with double trenches g, g, g', g³, with emptying pipes f, f, as before
explained. The steam introduced into the table by means of the
pipe heats the upper surface a, upon which the coverings which
receive the glasses to be silvered are placed. In order to avoid the
inconveniences of the methods employed up to this time I immerse these
coverings into trenches g¹, g', filled with water. It follows that by
the effect of capillary attraction in proportion as the covering becomes
heated the water in the trenches rises and spreads throughout the fabric,
which has the effect of producing upon the glasses the same result
as the steam arriving through the holes of the upper face of the table,
as previously explained. After the operation the steam is driven back
on opening the cock m. The liquid from the trenches will be renewed
as often as may be desired by means of the cocks of the pipes f,f.
The numerous and different experiments which I have made enable
me to obtain the same result by means of tables made of wood pro-
vided in the interior with very thin plate, lead, or zinc, gutta percha,
bituminous cardboard, or other insoluble material, metallic, vegetable, or
ceramic, and of a price very inferior to that of the tables of sheet or
cast iron. The upper surface of these tables of wood is formed by

page_text: means of perforated plates of cast or sheet iron of any shape united
to one another and allowing several glasses of different dimensions if
required to be silvered at the same time. These plates are supported by
an inner frame arranged for this purpose combined with the dimensions
of the table and fixed in a convenient manner.
And having now described the nature of the said Invention, and in
what manner the same is to be performed, I declare that I claim, the
'application of my new apparatus substantially as described, made either
from cast iron, sheet iron, zinc, earthenware, wood, or any suitable
mineral or vegetable substance to the silvering of glasses by the processes
or means above described.
In witness whereof, I, the said Claude Adolphe Maugin, have here-
unto set my hand and seal, this Twenty-sixth day of March, One
thousand eight hundred and seventy.