IMPROVEMENTS IN ELECTRO-PLATING AND DEPOSITING METALS
Year: 1857

page_text: LETTERS PATENT to Charles Cowper, of No. 20, Southampton Buildings,
Chancery Lane, in the County of Middlesex, Patent Agent, for the In-
vention of "IMPROVEMENTS IN ELECTRO-PLATING AND DEPOSITING METALS."-
A communication from Hyppolite Landois and Léon Daniel, of Paris, in
France.
Sealed the 2nd October 1857, and dated the 27th April 1857.
PROVISIONAL SPECIFICATION left by the said Charles Cowper at the
Office of the Commissioners of Patents, with his Petition, on the
27th April 1857.
I, CHARLES COWPER, of No. 20, Southampton Buildings, Chancery Lane,
in the County of Middlesex, Patent Agent, do hereby declare the nature of the
said Invention for "IMPROVEMENTS IN ELECTRO-PLATING AND DEPOSITING METALS,"
to be as follows:-
The bath or solution of silver or other metal to be deposited is prepared by
adding tartaric acid to a double cyanide of patassium and the required metal,
so as to precipitate a tartrate or bitartrate of potash, leaving the metal in the
solution, which is then in a fit state to be employed for the electro-dopostion
of the metal. Thus, to make a gold bath or solution, two ounces of chloride
of gold are dissolved in five pints of distilled water, to which are added about
five ounces, more or less, of cyanide of potassium, or a sufficient quantity to

page_text: convert the chloride of gold. into the double cyanide of gold and potassium.
The solution is placed in a stoppered glass vessel, and there is added about two
ounces of tartaric acid, or a sufficient quantity to precipitate the potash of the
cyanide in combination with the tartaric acid. The vessel is immediately
closed air-tight, or the liquid is submitted to pressure; when the tartrate has
precipitated and the reaction is complete, the vessel is opened and the liquid is
filtered; the tartrate remains on the filter, and the solution which passes
through the filter is then ready for use. If not sufficiently acid, about half an
ounce of tartaric acid is added to it. A silver bath or solution is prepared in
a similar manner, substituting nitrato of silver for chloride of gold. The silver
solution should be neutral, or nearly so. The above-mentioned proportions
admit of variation. Solutions of other metals are prepared in a similar
These solutions are capable of being employed for depositing metals
on a great variety of other metals.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Charles Cowper in the Great Seal Patent Office on the
17th October 1857.
TO ALL TO WHOM THESE PRESENTS SHALL. COME, I, CHARLES
COWPER, of No. 20, Southampton Buildings, Chancery Lane, in the County of
Middlesex, Patent Agent, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-seventh.day of April, in the year of our Lord
One thousand eight hundred and fifty-seven, in the twentieth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the
said Charles Cowper, Her special licence that I, the said Charles Cowper,
my executors, administrators, and assigns, or such others as I, the said
Charles Cowper, my exccutors, 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
ELECTRO-PLATING AND DEPOSITING METALS," communicated to me from Hyppolite
Landois and Léon Daniel, of Paris, in France, upon the condition (amongst
others) that I, the said Charles Cowper, my executors or administrators, by
an instrument in writing under my, or their, or one of their hands and seals,

page_text: 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 Charles Cowper, do hereby declare the
nature of the 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:-
The bath or solution of silver or other metal to be deposited is prepared by
adding tartaric acid to a double cyanide of potassium and the required metal,
so as to precipitate a tartrate or bitartrate of potash, leaving the metal in the
solution, which is then in a fit state to be employed for the electro-deposition
of the metel: Thus, to make a gold bath or solution, two ounces of chloride
of gold are dissolved in five pints of distilled water, to which are added about
five ounces, more or less, of cyanide of potassium, or a sufficient quantity to
convert the chloride of gold into the double cyanide of gold and potassium.
The solution is placed in a stoppered glass vessel, and there is added about
two ounces of tartaric acid, or a sufficient quantity to precipitate the potash of
the cyanide in combination with the tartaric acid. The vessel is immediately
closed air-tight by inserting the stopper, or the liquid is submitted to pressure
in any other manner, so as to confine the vapour of hydrocyanic acid, which
would otherwise escape. When the tartrate has precipitated and the reaction
is complete, the vessel is opened and the liquid is filtered; the tartate or
bitartrate remains on the filter, and the solution which passes through the filter
is then ready for use. If not sufficiently acid, about half an ounce of tartaric
acid is added to it. A silver bath or solution is prepared in a similar manner,
substituting nitrate of silver for chloride of gold. The silver solution should
be neutral, or nearly so. The above-mentioned proportions admit of variation;
care should of course be taken to avoid inhaling the poisonous vapours of
hydrocyanic acid which may escape in closing and opening the vessel.
These
Solutions of other metals are prepared in a similar manner.
solutions are employed in connection with a galvanic battery or other source
of electricity in the ordinary manner, and they are capable of being employed
for electro-plating and depositing metals on a great variety of other metals.
Having now described the nature of the Invention, and in what manner the
same is to be performed, I wish it to be understood that what I claim is, the
application in electro-plating and depositing metals of solutions of gold and
silver and other metals prepared by adding tartaric acid to a double cyanide of.

page_text: potassium and the required metal, and submitting the mixture to pressure
by closing the vessel containing it, or otherwise, as herein-before described.
In witness whereof, I, the said Charles Cowper, have hereunto set my
hand and seal, this Seventeenth day of October, in the year of our Lord
One thousand eight hundred and fifty-seven.
CHARLES COWPER. (L.S.)