AN IMPROVED GALVANO-PLASTIC PROCESS FOR DEPOSITING IRON, APPLICABLE FOR THE REPRODUCTION OF ENGRAVED SURFACES, STEREOTYPING, AND USEFUL AND ORNAMENTAL PURPOSES
Year: 1869

page_text: LETTERS PATENT to Maurice Herrmann Jacobi, of St. Petersburg, in
the Empire of Russia, and of 53, Chancery Lane, in the County
of Middlesex, Doctor of Philosophy, for the Invention of "AN
IMPROVED GALVANO-PLASTIC PROCESS FOR DEPOSITING IRON, APPLICABLE FOR
THE REPRODUCTION OF ENGRAVED SURFACES, STEREOTYPING, AND
USEFUL AND ORNAMENTAL PURPOSES."-Partly a communication from
abroad by Eugene Klein, Engineer, of St. Petersburg.
Sealed the 8th February 1870, and dated the 17th August 1869.
PROVISIONAL SPECIFICATION left by the said Maurice Herrmann
Jacobi at the Office of the Commissioners of Patents, with his
Petition, on the 17th August 1869.
I, MAURICE HERRMANN JACOBI, of St. Petersburg, in the Empire of
Russia, and of 53, Chancery Lane, in the County of Middlesex, Doctor
of Philosophy, do hereby declare the nature of the said Invention for
"AN IMPROVED GALVANO-PLASTIC PROCESS FOR DEPOSITING IRON, APPLICABLE, FOR
THE REPRODUCTION OF ENGRAVED SURFACES, STEREOTYPING, AND OTHER USEFUL
AND ORNAMENTAL PURPOSES," to be as follows:-
My Invention consists in the application of a practical galvano-plastic
process for depositing iron in moulds or otherwise for reproducing

page_text: purposes.
The galvano-plastic bath I use is composed of sulphate of iron
combined with the sulphates of either ammonia, potash, or soda, which
forms with sulphate of iron analogous double salts. The sulphate of
iron may also be used in connection with the chlorides of the said
alkalies, but I prefer the use of sulphates. The bath should be kept
as neutral as possible, though a small quantity of a weak organic acid
may be added in order to prevent the precipitation of salts of peroxide
of iron. A small quantity of gelatine will improve the texture of the
iron deposit.
As in all galvano-plastic processes the elevation of the
temperature of the bath contributes to the uniformity of the deposit
of iron and accelerates its formation, in order to maintain the con-
centration of the bath I use as anodes large iron plates or bundles of
wire of the same metal. Having observed that the spontaneous dis-
solution of the iron anode is in some cases insufficient to restore to
the bath all the iron deposited on the cathode, I find it useful to
combine the iron anode with a layer of gas coal or a plate of copper,
platinum, or any other metal being electro-negative towards iron, and
which I place in the bath itself. As a matter of course this negative
plate may also be placed in a separate porous cell filled with an exciting
fluid, such as diluted nitric or sulphuric acid, or the nitrates or sulphates
of potash and soda. For producing the current I usually take one or
two cells only of Daniell's or Smee's battery, the size of which is pro-
portionate to the surface of the cathode. The Daniell's cells should
have a large surface, and contain a solution of sulphate of magnesia
instead of diluted sulphuric acid. It is indispensable that the current
should be regulated and kept always uniform with the assistance of a
galvanometer having but few coils, and therefore offering only a small
resistance. The intensity of the current ought to be such as to admit
only of a very slight evolution of gas bubbles at the cathode, but it
would become prejudicial to the beauty of the deposit if gas bubbles
were allowed to adhere to its surface. The same moulds as are employed
for depositing copper may also be used for depositing iron according to
this improved process, only it is advisable in employing moulds made of
lead or gutta percha to coat them previously with a thin film of copper
deposited in the usual way by the aid of galvanism, and then bring
them, after being washed with water, immediately into the iron bath.

page_text: This film of copper may be removed from the deposit either by me-
chanical means or by immersion in strong nitric acid. The deposited
iron-is very hard and rather brittle, so that some precautions must be
taken in separating it from the mould. By annealing it acquires the
malleability and softness of tempered steel.
After many trials with different substances I have found the best
proportions for the iron galvano-plastic bath to consist in a mixture of
139 parts of sulphate of iron and 123 parts of sulphate of magnesia
dissolved together in hot water with the addition of some oxalic acid and
iron shavings. I do not, however, intend to limit myself to the above
proportions. This solution it is best to keep in a concentrated state in
well closed glass vessels. When used it should be diluted with water so
as to have a specific gravity of 1155, pure water having 1000. The
oxide of iron appearing on the surface of the iron galvano-plastic bath
should be taken off daily together with some of the solution, which is
then shaken in a bottle with some carbonate of magnesia, and may after
the formation of the sediment be again added to the bath. The iron
deposit has a particularly fine appearance if brushed from time to time
with some carbonate of magnesia. In order to prevent air bubbles
adhering to the mould while dipped in the bath the surface of the
mould should be previously well washed first with alcohol and then
with water, after which it is to be placed immediately in the bath
before drying.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Maurice Herrmann Jacobi in the Great Seal Patent
Office on the 15th February 1870.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, MAURICE
HERRMANN JACOBI, of St. Petersburg, in the Empire of Russia, and of
53, Chancery Lane, in the County of Middlesex, Doctor of Philosophy,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent bearing date the Seventeenth day of August, 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 Maurice Herrmann Jacobi, Her special licence

page_text: that I, the said Maurice Herrmann Jacobi, my executors, administrators,
and assigns, or such others as I, the said Maurice Herrmann Jacobi, 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 "AN IMPROVED
GALVANO-PLASTIC PROCESS FOR DEPOSITING IRON, APPLICABLE FOR THE REPRODUCTION
OF ENGRAVED SURFACES, STEREOTYPING, AND OTHER USEFUL AND ORNAMENTAL
PURPOSES," partly my own Invention and partly a communication to me
from abroad by Eugene Klein, Engineer, of St. Petersburg, aforesaid,
upon the condition (amongst others) that I, the said Maurice Herrmann
Jacobi, 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 Maurice Herrmann Jacobi, 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 (that is to say) :-
-:
My Invention consists in the application of a practical galvano-plastic
process for depositing iron in moulds or otherwise for reproducing
engraved surfaces, stereotyping, and for other useful or ornamental
purposes.
The galvano-plastic bath I use is composed of sulphate or chloride
of iron combined with the sulphate or chloride of ammonia, potash, or
soda, or combinations of them, either with or without other salts (such
as the soluble salts of alkaline earths, magnesium or calcium for
instance), but I prefer using them when combined in such proportions
as will form compound or double salts, although I do not confine myself
to strict equivalent proportions. The bath should be kept as neutral
as possible, though a small quantity of a weak organic acid may be
'added in order to prevent the precipitation of peroxide of iron. A small
quantity of gelatine will improve the texture of the iron deposit. As
in all galvano-plastic processes the elevation of the temperature of the
ath contributes to the uniformity of the deposit of iron and accele-

page_text: rates its formation, in order to maintain the concentration of the bath
I use as anodes large iron plates or bundles of iron wire. Having
observed that the spontaneous dissolution of the iron anode is in some
cases insufficient to restore to the bath all the iron deposited on the
cathode, I find it useful to combine the iron anode with pieces of gas
coal or other form of carbon, or with a plate of copper, platinum, or any
other metal being electro-negative towards iron. I place the pieces or
plates in the bath itself, but it is better to make the containing vessel
of such metal electro-negative to iron and preferably of copper. This
negative plate may also be placed in a separate porous cell filled with
an exciting fluid, such as dilute nitric or sulphuric acid, or the nitrates
or sulphates of potash or soda. For producing the current I usually
take one or two cells of Daniell's, Smee's, or of any other suitable
galvanic battery, the size of which is proportionate to the surface of
the cathode. When using Daniell's cells they should have a large
surface, and contain a solution of sulphate of magnesia instead of diluted
sulphuric acid. For producing the electric current I may employ a
magneto-electric battery in place of a galvanic battery. It is indispensible
that the current should be regulated and kept always uniform with the
assistance of a galvanometer having but few coils, and therefore offering
only a small resistance. The intensity of the current should be such as
to admit only of a very slight evolution of gas bubbles at the cathode, but
it would become prejudicial to the beauty of the deposit if gas bubbles
were allowed to adhere to its surface.
Moulds similar to those used for depositing copper may also be used
for depositing iron according to this improved process, only it is advisable
when employing moulds made of lead or gutta percha or other suitable
materials to coat them previously with a thin film of copper deposited
in the usual way by the aid of galvanism, and then bring them after
being washed in water immediately into the iron bath. If on removal
of the deposit of iron from the mould the copper film should adhere it
can be removed by mechanical means or by immersion in strong nitric
acid. But the best and surest method is to make the deposit the anode
in a bath of strong cyanide of potassium, which will rapidly dissolve
the film of copper without in the least injuring the iron. The deposited
iron is very hard and rather brittle, so that some precaution must be
taken in separating it from the mould. By annealing it acquires the
malleability of tempered steel.

page_text: After many trials with different substances I have found the best
proportions for the iron galvano-plastic bath to consist of 139 parts of
sulphate of iron and 123 parts of sulphate of magnesia dissolved together
in hot water with the addition of some oxalic acid and iron shavings.
I do not, however, intend to limit myself to the above proportions.
This solution is best kept in a concentrated state in well closed glass
vessels. When used it should be diluted with water, so as to have a
specific gravity of 1155, or near it, pure water having 1000. The
oxide of iron appearing on the surface of the iron galvano-plastic bath
should be taken off daily, together with some of the solution, which is
then shaken in a vessel with some carbonate of magnesia, and may after
the formation of the sediment be again added to the bath. The iron
deposit presents a particularly fine appearance if brushed from time.to
time with some carbonate of magnesia. In order to prevent air bubbles
adhering to the mould while dipped in the bath the surface of the mould
should be previously well washed, first with alcohol and then with
water, after which it is to be placed immediately in the bath before
drying.
Having described the nature of my Invention, and the manner of
performing the same, I declare that what I claim as my Invention
to be protected by the herein-before in part recited Letters Patent is,
depositing iron, as and for the purposes herein-before mentioned, by
means of the improved galvano-plastic process described, in which the
bath is composed of compound or double salts formed by the com-
bination of sulphate or chloride of iron with one or more of the other
salts herein-before specified.
In witness whereof, I, the said Maurice Herrmann Jacobi, have
hereunto set my hand and seal, this Ninth day of February, in the
year of our Lord One thousand eight hundred and seventy.
MAURICE HERRMANN JACOBI. (L.S.)