CERTAIN IMPROVEMENTS IN THE PRODUCTION OF WORKS OF ART IN METAL BY ELECTRIC DEPOSITION
Year: 1841

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ALEXANDER
PARKES, of Birmingham, in the County of Warwick, Artist, send greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Letters Patent under the Great Seal of Great Britain, bearing date at West-
minster, the Twenty-ninth day of March, in the fourth year of Her- reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
Alexander Parkes, Her especial licence, full power, sole privilege and autho-
rity, that I, the said Alexander Parkes, .my exors, admors, and assigns, or
such others as I, the said Alexander Parkes, my exors, admors, or assigns,
should at any time agree with, and no others, from time to time and at
all times during the term of years therein expressed, should and lawfully
might make, use, exercise, and vend, within England, Wales, and the Town
of Berwick-upon-Tweed, my Invention of "CERTAIN IMPROVEMENTS IN THE
PRODUCTION OF WORKS OF ART IN METAL BY ELECTRIC DEPOSITION;" in which said
Letters Patent is contained a proviso, that I, the said Alexander Parkes, shall
cause a particular description of the nature of my said Invention, and in what
manner the same is to be performed, to be inrolled in. Her said Majesty's
High Court of Chancery within six calendar months next and immediately
after the date of the said in part recited Letters Patent, as in and by the sanie,
reference being thereunto had, will more fully and at large appear.

page_text: NOW KNOW YE, that in compliance with the said proviso, I, the said
Alexander Parkes, do hereby declare that the nature of my Invention, and
the manner in which the same is to be performed, are fully described and
ascertained in and by the following statement thereof, reference being had to
the Drawing hereunto annexed, and to the figures and letters marked thereon
(that is to say)—
My Invention relates to the manufacture of works of art of silver and of
gold, by causing these metals to be deposited by electric agency in or on
suitable moulds or models. And in order that my Invention may be most fully
understood and readily carried into effect, I will proceed to describe the means
pursued by me, and which I have found fully to answer; but I would first
remark, that in making works of art of gold or of silver, as heretofore practised,
two modes have been resorted to; first, that of casting, and which is performed
by casting molten gold or silver in suitable moulds of sand and other materials,
and subsequently finishing by gravers and other tools, as is well understood;
and, secondly, by obtaining gold or silver in sheets, and by means of dies and
pressure, or by hammering or stamping the same, the desired form or pattern
of the sheet metal is produced, and the surfaces of which, in some cases, are
afterwards ornamented by hand by the graver and other tools, as is also well
understood. And I would further remark, that I am aware that silver and
gold bave been deposited from a state of solution on to copper and other metal
surfaces by means of electric currents, for the purpose of permanently gilding
and of silvering such metal surfaces, and a Patent was obtained by George
Richards Elkington and Henry Elkington, of Birmingham, on the 25th day of
March 1840, for such purposes. I mention this circumstance in order to
state that I do not claim the depositing of gold or of silver on to metallic
surfaces, excepting when the process is so conducted that the moulds or models
used in producing any articles in gold or silver according to my Invention may
be removed by heat or otherwise from the deposition of gold or of silver, and
thus obtain the articles desired in gold or in silver, in place of producing such
articles by casting, or by pressure, or hanimering, or stamping in. dies or shapes,
as heretofore practised. The shapes of articles made in gold and silver. for
ornamental, household, and other purposes being so various, it will not be
necessary for nie to enter into a description of the formation of moulds, or
models for every article, as a description of the means pursued in manufac
turing a few articles of gold and silver will enable the workman to make
suitalile moulds or models for. other articles which he may desire. to make of
gold or silver. And to facilitate the workman in: understanding my Invention;
I would state that I prefer to use the following solution of gold when articles.

page_text: of gold are desired to be made according to my Invention:-Take one ounce
of pure gold and dissolve it in aqua regia,, evaporate' the same to dryness'
upon a sand bath,. then add two gallons of water and sixteen' ounces of prussiate
of potash (cyanide of potassium). I use this solution' at about 120 to 180°
of Fabrenlicit, and in-combination with electric currents, as horeafter described;'
andi when articles in silver are desired to be made according to my' Invention,
I prefer to employ the following solution of silver: Dissolve one ounce' pure'
silver in nitric acid, and precipitate the same by the aildition of lime water, as
oxide: of silver; having: well waslied this oxide; add two gallons of water and
one pound of prussiate of potash (cyanide of potassium); when' wax moulds or
models are used I prefer to use more water. I use this solution' cold, and in
combination with electric currents, as hereafter described; but I do not confine
myself to such solutions as others' may be employed, my Invention' nöt relating
to the mode of preparing suitable solutions of gold and of silver to be acted ori
by electric means to obtain depositions on. moulds or models in the carrying
out my Invention:
I will now proceed to describe the kinds of moulds or models which I prefer
to use in carrying out my Invention, which are eitlier of metal, or have
metallic' or electric conducting surfaces produced thereto, where the deposition
of gold or of silver is to take place: I shall divide my description' of these
moulds or models into two classes;: first, those where the required déposit' or
article is produced within them; and; secondly, where the deposit is obtained
upon or outside: these moulds or models; and I have found the former more
suitable to copy, such articles as busts, figures, and drinking and other vessels;
and the second more: suitable for flowers; leafage, scroll: work; and other pur-
poses where the pattern or ornament is more elaborate or complex.
The materials I employ are the same for both description of moulds, and are
either metallic or non-metallic;; if the latter, it should be understood that they
are in all cases when used to be prepared upon their surfaces in such manner
as to become conductors of electricity, and which is effected by a coating of
bronze or other conducting agent, as is well-known and in practice in obtaining:
electrotype impressions in copper..
In order to produce a mould 'within which I intend to deposit an article, I'
first have before me a perfect pattern of the subject' required; and the form or
substance of this pattern will generally influence the choice of the material to
be used for the moulds: If the pattern be formed of metal or plaster of paris,
I prefer the metallic or fusible metals, hereafter described, or wax or stearine:
may be employed. If the pattern be of wax, or of a substance that will not
bear the heat of the melted' metal or melted wax or stearine, I use plaster of

page_text: paris in forming the mould or models, and saturate them with tallow, and
bronze the surface, as before directed.
In order to produce moulds to be deposited upon internally I proceed as
follows: Having prepared a plaster model or mould in- the usual way, in parts,
of the article to be made in gold or silver, I take the pattern with the plaister
mould thereon, I remove one of the pieces of the plaster mould and run into
the space left vacant melted fusible metal, or wax, or stearine, and thus obtain
a portion of a mould, which I remove and replace the portion of plaster cast,
and next remove another portion of the plaster cast and run in melted metal,
wax, or stearine, and thus obtain another portion of the mould in the material
desired, and so on, till I obtain a complete mould; these parts or portions of a
mould are then bound together with wire or other material, and are to receive
the deposit of gold or silver. If carefully performed, all the sharpness of the
original pattern will be preserved, and the same mould may be employed to
obtain a number of deposited copies.
Another method of producing articles in gold or silver from internal moulds
is as follows: Having prepared a plaster mould as before described, and the
pattern removed, I pour therein. some one of the substances before directed; if
I use wax or stearine, I prefer to have the plaster mould first saturated with
warm water, and having poured in sufficient of the substance to form a hollow
mould strong enough to bear handling, I keep the mould in motion until the
wax or stearine be cold; I then remove the cast of wax or stearine. If I use a
fusible metal, I introduce a core of sand or of plaster of paris (in parts, if
necessary), leaving a space between the core and the mould (into which space
pour the fusible metal.
I now proceed to deposit upon the external surface
I
of such models or moulds a coating of copper, and when the same is strong
enough to serve as the mould I melt out the internal substance.
I have now
a copper mould, in which is to be produced in gold or silver the article desired,
and having made the same perfectly clean, and protected the outer surface with
wax or clay coated with a solution of caoutchouc, I proceed to deposit gold or
silver therein, as hereafter directed, and when I have obtained a sufficient
thickness I remove the copper mould by dissolving the same, or by mechanical
means; if I dissolve, I use muriatic acid in a hot state, having colcothar (per-
oxide of iron) in combination with it; but as these moulds are destroyed after
producing one copy, I sometimes use metal moulds made in parts, by depositing
metal by electric agency, so as to fit together and make a perfect mould, by
which several of the articles may be made of gold or silver. I also sometimes
use moulds or models (in parts, when required) prepared or cast of brass or
other metals, the surfaces being subsequently chased on ground, or highly

page_text: finished and fitted together, but these are only desirable where a considerable
number of copies may be required of one article. In order to produce moulds
of the second description, or where the deposit required is obtained outside the
mould, I use the same substances as directed for moulds of the first class.
If fusible metals are used, they may be cast in sand from patterns, as is
practised for casting brass, silver, and other metals, care being taken to have
the sand well "faced," as is practised for fine castings, and the moulds dried
and cooled before pouring the fusible metal. If wax or stearine are to be used,
I employ plaster of paris moulds to produce the mould or model, and I some-
times cast fusible metals for models or moulds in plaster of paris moulds..
Having obtained the desired mould or model, I proceed to deposit gold or silver
thereon, and when using these moulds I cause the deposition to proceed slowly,
in order to obtain the external surface smooth. When I have obtained
sufficient strength of deposit I remove the internal core by heat or otherwise,
according to the nature of the substance used for the model or mould. If
after cleaning the same I require more strength of metal than I have obtained
by this external deposition, I protect the outer surface by wax or clay and
caoutchouc, as before explained, and proceed to deposit a further quantity
within, in the same manner as directed for depositing within an inner mould,
and this may be carried on more rapidly, as a slight roughness of surface inside
is seldom an objection.
. I would remark, that I do not confine myself to the use of the materials
above mentioned for making moulds or models for receiving depositions of gold
or silver by electric means, as other materials may be used, but I believe those
above mentioned will be found best for all purposes.
The fusible metals I prefer for the above-described purposes vary according
to the kind and size of the mould or model desired; I prefer No. 1, stated
below, or No. 3, for fine work; No. 2 and No. 4 for larger articles.
Fusible metal, No. 1, fourteen parts by weight bismuth, sixteen parts of
mercury, and thirty-two parts of lead. No. 2,.four parts bismuth, four parts
lead, one part tin, and one part mercury. No. 3, two parts of lead and one
part bismuth. No. 4, three parts bismuth, six parts lead, one part antimony.
I prefer to pour the fusible metals at as low a heat as they remain fluid.;
and in order to do this, I keep the same, if of No. 1 or No. 2, heated over
boiling water, and No. 3 & 4 over a gas burner, in a vessel with a tap or plug
at the bottom, which will prevent any oxidized portion of the metal flowing
upon the surface from injuring the cast. In some cases I make the pattern
upon which the mould or model is to be cast in pieces, and finish or work it
up to the desired design, the parts being so formed as to separate and be

page_text: removed from: within a casting, produced on the outer surface, and in obtaining
a: casting, or mould from such, pattern I, place it, as a core, in a hollow mould,.
and run, the melted material between the pattern and the mould,. and when
cold I.remove; the parts. of. the pattern.. I thus obtain a hollow mould in one.
piece, and receive-thie. deposition: of gold or silver therein,, and, then.remove the
moull by heat or otherwise; depending on the material used..
The use, of electric; agency, in precipitating. metals: being, now well under-
stood; it will. not. be, necessary to enter into any description of the various.
means of obtaining it,.further than to state that.I prefer to use: the compound
or independent: battery, by which the, electric current is, conveyed from the
.battery, into, an. adjoining cell, or vessel containing: the solution of: gold or of
silver,, and also a plate of gold.or of silver. to be dissolved during, the continu--
ance off the deposition.. This plate may be made. to surround.the. whole.of the
interior of the cell' where: the: deposition is taking place.upon the moulds; but.
when, the, deposition is upon. internal moulds, I prefer to. bave a plate. or. wire
of silver, or. gold introduced. within, the, mould;, and in connection. with the
negative plate of the:battery,
Having thus stated the nature of the solutions.of gold: and silver which I
prefer to use, and, also the nature of moulds. employed, I will proceed: to
describe, by aid of the annexed: Drawings, the means pursued by me ini pro-
ducing any article of gold or silver according to my Invention; and in.doing, so
I will suppose the article desired to be obtained: is: a vase, as represented in
Figure 1, where A represents a wire from the positive plate in connection.with
the mouldiC; B, the; wire from the negative. plate. in connection with. B', which
is a plate of gold or silver, to be.dissolved;: E represents a solution. of gold or
silver within and without the model or mould C.
In: Figure 2,,C represents a mould. or model of a branch, upon; the external
surface of which the deposition of gold or silver is supposed to be. proceeding;
B, a plate ofigold or silver surrounding the model.or mould: C,,and.immersed
in a solution of gold or silver: E..
:
In Figure,3,.F represents a:copper.deposited model.or: mould,,within which
the deposition of gold or silver is desired to be obtained';, the other letters of
reference are used to denote the same things as in Figure 1..
Having produced the article desired in gold or in silver, if it :bc.a bust.or figure
or ornament, and requires.to.be.of greater strength than it is desired to obtain
by, a,thickness of gold or silver, I strengthen the article. by: causing a deposit of
copper or other metal by electric: means within the article of silver or gold, or
Ifill the article of gold or silver with fusible metal or other material.
Having thus described the nature of my Invention, and the manner of per-

page_text: forming the same, I would wish it to be understood that what I claim as the
Invention secured under the above-recited Letters Patent is,―
First, the mode of manufacturing articles of gold and silver by depositions
thereof by electric agency in or on suitable moulds or models, which may be
removed from the articles of gold or silver when the same have been formed,
as above described.
Secondly, I claim the mode of manufacturing articles of gold or silver on or
in metal moulds or models which are deposited by electric means, such moulds
or models being afterwards removed, as described.
Thirdly, I claim the mode of manufacturing articles of gold or silver by
electric deposition on or in moulds or models, when such moulds or models are
removed by heat or solution.
Fourthly, I claim the mode of manufacturing articles of gold or silver by
electric deposition in or on moulds or models made up of parts.
Fifthly, I claim the mode of strengthening articles of gold and silver pro-
duced in or on moulds by electric depositions, by introducing a baser metal
within them.
In witness whereof, I, the said Alexander Parkes, have hereunto set
my hand and seal, this Twenty-eighth day of September, in the year
of our Lord One thousand eight hundred and forty-one.
ALEXANDER (L.S.)
(L.s.) PARKES.
AND BE IT REMEMBERED, that on the Twenty-eighth day of Sep-
tember, in the year of our Lord 1841, the aforesaid Alexander Parkes came
before our said Lady the Queen in Her Chancery, and acknowledged the
Specification aforesaid, and all and every thing therein contained and specified,
in form above written. And also the Specification aforesaid was stamped
according to the tenor of the Statute made for that purpose.
Inrolled the Twenty-ninth day of September, in the year of our Lord One
thousand eight hundred and forty-one.