AN IMPROVED PROCESS OF GILDING on Glass.’ IMPROVED PROCESS OF GILDIng on Glass
Year: 1873

page_text: LETTERS PATENT to Valentin Schwarzenbach, Professor of Chemistry,.
at the University of Berne, Switzerland, for the Invention of "AN
IMPROVED PROCESS OF GILDING on Glass.’
IMPROVED PROCESS OF GILDIng on Glass.”
Scaled the 4th July 1873, and dated the 18th January 1873.
PROVISIONAL SPECIFICATION left by the said Valentin Schwarzenbachi
at the Office of the Commissioners of Patents, with his. Petition,
on the 18th January 1873.
I, VALENTIN SCHWARZENBACH, Professor of Chemistry, at the Univer- .
sity of Berne, Switzerland, do hereby declare the nature of the said
Invention of "AN IMPROVED PROCESS OF GILDING ON GLASS," to be as;
follows:-
:-
Take a solution of pure gold, that is to say, free from all other metals,
effected by the ordinary chemical process; when pure gold is employed
the work is simple, since it, is merely necessary to melt it in aqua regia
or nitro-muriatic acid, and to evaporate it in the bain maric till it
crystallizes in all other cases the operation is more complicated on
account of the manipulations necessary for separating the other metals,
and it is generally requisite to precipitate the gold once by oxalic
acid or by sulphate of iron to bring it to the desired state of purity.

page_text: In all cases the crystallized mass of perchlorate of gold should be
brought to boiling point with the water destined for its solution as it
invariably contains a considerable quantity of chlorid of gold insoluble
in water, which slowly decomposes in a cold state, very gently in per-
chlorate or in metal, but which is instantly effected by coction.
After filtration the solution of gold is ready for use, its dephlegmation
is regulated so that 200 cubic centimètres contain 1 grain of metallic
gold; this solution is then rendered alkaline by soda lye of mean
strength, that is to say, a sufficient quantity is added to it to turn red
litmus paper blue;
the addition of the soda should not cause any pre-
cipitate and should never trouble the auriferous liquor; the quantity of
soda must necessarily vary according to the dephlegmation of the
solution.
Before mixing the solution of gold with the principal reactive destined
to the reduction of the metal it is indispensable to prepare the surface
of the glass to be gilt with the greatest care, employing the same mani-
pulations and materials used for cleaning photographic glasses; the
reactive reductive is then prepared by saturating 30 per cent. of spirits
of wine with a current or mixture of marsh gas, or olcfiant gas; this
operation completed the spirits of wine is freed with its volume of
distilled water.
The glass to be gilt is then disposed horizontally on another surface
of glass, separated from it about the space of 3 millimètres, then 25
cubic centimètres of alcohol saturated with the gases is mixed with tho
auriferous solution, the liquid is then poured between the two glasses,
and then left to stand for 2 or 3 hours, at the expiration of which
time the gilding is completed. The upper gilt plate is then removed,
carefully washed and varnished.

page_text: WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Eighteenth day of January, in
the year of our Lord One thousand eight hundred and seventy-three, in
the thirty-sixth year of Her reign, did, for Herself, Her heirs and
successors, give and grant unto me, the said Valentin Schwarzenbach, Her
special licence that I, the said Valentin Schwarzenbach, my executors,
administrators, and assigns, or such others as I, the said Valentin Schwar-
zenbach,
1, my exccutors, administrators, and assigns, should at any time
agree with, and no others, from time to time and at all times there-
after 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 "AN IMPROVED PROCESS OF GILDING ON GLASS," upon the condition
(amongst others) that I, the said Valentin Schwarzenbach, my executors
or administrators, by an instrument in writing under my, or their, or one
of their hands and seals, 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
Office within six calendar months next and immediately after the date
of the said Letters Patent.
NOW KNOW YE, that I, the said Valentin Schwarzenbach, 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:-
Take a solution of pure gold, that is to say, free from all other metals,
effected by the ordinary chemical process; when pure gold is employed
the work is simple, since it is merely necessary to melt it in aqua regia
or nitro-muriatic acid and to evaporate it in the bain mario till it
crystallizes; in all other cases the operation is more complicated by the
necessary manipulations for separating the other metals, and it is
generally requisite to precipitate the gold once by oxalic acid, or by
sulphate of iron to bring it to the desired state of purity.
In all cases the crystallized mass of perchlorate of gold should be
brought to boiling point with the water destined for its solution as it
invariably contains a considerable quantity of chlorid of gold insoluble
in water, which only decomposes in a cold state very gently in per-
chlorate or in motal, but which is instantly effected by coction.

page_text: After filtration the solution of gold is ready for use, its dephlegmation
is regulated so that 200 cubic centimètres contain one grain of metallic
gold; this solution is thon rendered alkaline by soda lye of mean
strength, that is to say, a sufficient quantity is added to it to turn red
litmus paper blue; the addition of the soda should not cause any pre-
cipitate, and should never trouble the auriferous liquor; the quantity of
soda must necessarily vary according to the deplegmation of the
solution.
Before mixing the solution of gold with the principal reactive destined
to the reduction of the metal it is indispensable to prepare the surface 1
of the glass to be gilt with the greatest care, employing the same mani-
pulations and materials used for cleaning photographic glasses; the
reactive reductive is then prepared by suturating 30 per cent. of spirits
of wine with a current or mixture of marsh gas or olefiant gas; the
operation completed the spirits of wine is freed with its volume of
distilled water.
The glass to be gilt is then disposed horizontally on another surface of
glass, separated from it about the space of 3 millimètres, then 25 cubic
centimètres of alcohol saturated with the gases is mixed with the auri-
ferous solution, the liquid is then poured between the two glasses, leaving 2
the whole to stand for 2 or 3 hours, at the expiration of which
time the gilding is completed. The upper gilt plato is then removed,
washed carefully and varnished.
In witness whereof, I, the said Valentin Schwarzenbach have here-
unto set my hand and seal, this Twenty-fourth day of June, in
the year of our Lord One thousand eight hundred and seventy-
three.
VALENTIN SCHWARZENBACH, D.M. (L.S.)