IMPROVEMENTS IN SILVERING GILDING. AND PLATINIZING GLASS
Year: 1855

page_text: LETTERS PATENT to Tony Petitjean, of Tottenham Court Road, in the
County of Middlesex, Chemist, for the Invention of "IMPROVEMENTS IN
SILVERING GILDING. AND PLATINIZING GLASS."
PROVISIONAL SPECIFICATION left by the said Tony Petitjean at the
Office of the Commissioners of Patents, with his Petition, on the 24th
July 1855.
I, TONY PETITJEAN, of Tottenham Court Road, in the County of Middlesex,
Chemist, do hereby declare the nature of the said Invention for "IMPROVEMENTS
IN SILVERING, GILDING, AND PLATINIZING GLASS," to be as follows:-
My Invention consists in coating glass with a solution or product obtained
by combining vegetable acids or hydro-acids, (or these acids combined with
chlorine, iodine, or bromine,) with a metallic salt of silver, gold, or platinum,
the bases of which are easily reducible, and are combined with mineral acids
or hydro-acids. An alkali must be mixed with the metallic salt or with the
vegetable acid.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Tony Petitjean in the Great Seal Patent Office on the
24th January 1856.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, TONY
PETITJEAN, of Tottenham Court Road, in the County of Middlesex, Chemist,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-fourth day of July, in the year of our Lord
One thousand eight hundred and fifty-five, in the nineteenth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said Tony Petitjean, Her special licence that I, the said Tony Petitjean, my
executors, administrators, and assigns, or such others as I, the said Tony
Petitjean, 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 and Ireland, the Channel
Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN SILVERING,
GILDING, AND PLATINIZING GLASS," upon the condition (amongst others) that
1, the said Tony Petitjean, by an instrument in writing under my hand
and seal, should particularly 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 Oflice within six calendar months
next and immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Tony Petitjean, do hereby declare the
nature of my said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement thereof, that is to say:-
My Invention consists in coating glass with solutions or products obtained
by combining vegetable acids or hydracids (or these combined with chlorine,
iodine, or bromine,) with metallic salts of silver, gold, or platinum, the bases of a
which are combined with mineral acids or hydracids. An alkali must be
mixed with the metallic salt or with the vegetable acid.
The following are examples of the manner in which my Invention may be
-carried into effect:-
TO SILVER GLASS.
In order to silver glass I first prepare two solutions of silver.
Solution No. 1 is formed by combining four chemical equivalents of ammo-
niacal nitrate of silver with one equivalent of tartaric acid and a suitable

page_text: quantity of distilled water. To ten and a half ounces of nitrate of silver I add
six and a half ounces of liquid ammonia. I pour the ammonia upon the nitrate
of silver, the combination of the two being attended with a disengagement of
heat. I stir the mixture until the combination of the two is complete, and
then stand it by for several hours, after which crystals of ammoniacal nitrate
of silver are formed. I then add to the solution two pints and a half of dis-
tilled water, and stir the whole well in order to assist the crystals to dissolve.
I then filter the solution in order to separate from it a small quantity of black
powder which is formed during the combination of the nitrate of silver and the
ammonia, and add to the filtered liquid one and one-sixth ounces of tartaric
acid dissolved in four times that weight of distilled water, repeating the stirring
as before. I subsequently add six quarts of distilled water, stir the whole well,
and then leave it to stand for decanting. Upon the precipitate of tartrate of
silver which is left after the decanting has taken place, I pour from seven to
eight quarts of distilled water in order to dissolve as much as possible of it, and
stir and leave it to stand for a sufficient time, after which I decant the liquor
and mix it with the first solution. I thus obtain about fifteen quarts of a
solution of silver, to which I add two quarts of distilled water in order to make
it perfectly limpid. The solution is then quite ready for usc. What remains
of the precipitate of tartrate of silver after the liquor is the second time
decanted from it, is dissolved by means of a few drops of nitric acid, and
laid aside.
Solution No. 2 is formed by combining two chemical equivalents of ammo-
niacal nitrate of silver with one equivalent of tartaric acid and a suitable
quantity of distilled water. All the manipulations gone through in the pre-
paration of this solution are the same as in the case of solution No. 1, the only
difference between the two solutions being that the quantity of tartaric acid in
No. 2 is double that in No. 1. I should here observe, that these solutions
should be prepared for one day's use only.
The glass to be silvered should be well cleaned before it is operated upon.
For this purpose, I take a little of the solution No. 1, and dip slightly into it
a piece of cotton, and add to the moistened cotton a little putty powder, and
then rub it very carefully all over the surface of the glass, which is afterwards
allowed to dry. I then take a second piece of cotton perfectly clean and dry,
and placing upon it a little dry putty powder, rub it very carefully and slowly
over every part of the surface of the glass, moving it in straight lines as
nearly parallel as possible; after this I dust the glass with a badger brush,
in order to remove any fragments of powder that may remain upon it. I then
take (for looking glasses only) a roller formed of iron or wood, and covered with

page_text: india-rubber perfectly clean, and after wetting the india-rubber with No. 1
solution, rub it quickly over the glass, occasionally turning the roller a little
round as the rubbing is proceeded with. I then lay the glass upon a suitable
apparatus heated to about 150° Fahrenheit, and pour upon it No. 1 solution
until all the surface of the glass is covered with the liquid. In about fifteen
or twenty minutes a thin coating of silver is seen to be deposited all over the
surface of the glass, and I then pour upon it as much of No. 2 solution as the
surface can retain. (The surface will retain about half a pint of the liquid on
cach square foot of it.) I then leave the glass with the liquid upon it for about
fifteen minutes (or twenty minutes at most), in which time the coating of silver
is so much increased in thickness by a deposit from the second solution that it
becomes opaque. (One pennyweight of silver is thus deposited upon every
square foot of the surface of the glass.) After removing from it the excess of
the solution, I now take the glass, and after well washing the coating of silver
with warm water in order to cleanse the surface from any remains of the
solution, I dry it, and coat the silver surface with quickly-drying oil color or
brown varnish. In this manner I obtain a looking glass incomparably finer,
lighter, and more solidly coated than those made by the common process, and
that too without in any way injuring the health of the operator.
Glasses which are of such shapes that they cannot be cleaned by the process
hercin-before described, such as smelling bottles, for example, are first plunged
into a strong solution of hyposulphite of soda, and left to lie in it for ten or
twelve hours. They are then washed several times, and filled with solutions
No. 1 and No. 2 successively.
I do not necessarily require to heat the glass, as the deposition from the
solutions takes place at either high or low temperatures, but the rapidity of
the action increases with an increase of heat, and vice versa.
To GILD AND PLATINIZE GLASS.
The operations berein-before described in reference to the silvering of glass
are repeated in the gilding and platinizing of glass with no other alteration
except that a change is made in the solutions employed, the solutions of silver
being replaced by solutions of gold and platinum respectively, and that one
solution of gold and one of platinum only are needed. I shall therefore require
to do no more-than-describe these latter solutions, in order to make the method
of carrying this part of my Invention into effect clearly understood.
Solution of gold.-This solution is formed by combining two chemical
equivalents of per-chloride of gold with one equivalent of citrate of ammonia.
In a quart of distilled water I dissolve one ounce of chloride of gold and

page_text: filter the mixture; I then mix ten and a half drachms of citric acid previously
dissolved in four or five times its weight of distilled water with five and a half
drachms of liquid ammonia. After allowing this mixture to stand an hour or
more to cool, I pour it into the mixture of chloride of gold and water, and the
resulting mixture is the solution of gold which I require. This solution should
not be prepared until it is required for use.
Solution of platinum.-This solution is formed by combining one chemical
equivalent of per-chloride of platinum with one equivalent of bitartrate of soda.
In a quart of distilled water I dissolve one ounce of chloride of platinum and
filter the mixture; I then add to it thirteen drachms of bitartrate of soda
previously dissolved in eight or nine times its weight of distilled water, and
after well stirring the whole the solution is ready for use.
In the foregoing examples of the manner in which my Invention may be
carried into effect, I have selected chemicals which are cheap and easily acces-
sible; but there are of course many others which may be used in carrying out
the principle of my Invention.
And having now described the nature of my said Invention, and in what
manner the same is to be performed, I declare that I claim,―
First, coating glass with solutions or products obtained by combining vege-
table acids or hydracids (or these combined with chlorine, iodine, or bromine,)
with metallic salts of silver, gold, or platinum, the bases of which are combined
with mineral acids or bydracids, an alkali being combined with the metallic
salt or with the vegetable acid.
Second, the several processes herein-before described.
In witness whereof, I, the said Tony l'etitjean, have hereunto set my
hand and seal, this Twenty-first day of January, One thousand eight
hundred and fifty-six.
T. PETITJEAN.
(L.S.