IMPROVEMENTS IN PROVISIONAL SPECIFICATION
Year: 1873

page_text: LETTERS PATENT to Desmond Gerald Fitz-Gerald, of 6, Loughborough
Road North, in the County of Surrey, Electrician, and Bernard
Charles Molloy, of 1, Elm Court, Temple, in the County of
Middlesex, Barrister-at-Law, for the Invention of "IMPROVEMENTS IN
PROVISIONAL SPECIFICATION left by the said Desmond Gerald Fitz-
Gerald and Bernard Charles Molloy at the Office of the Com-
missioners of Patents, with their Petition, on the 13th June 1873.
We, DESMOND GERALD FITZ-GERALD, of 6, Loughborough Road
North, in the County of Surrey, Electrician, and BERNARD CHARLES
MOLLOY, of 1, Elm Court, Temple, in the County of Middlesex, Barrister-
at-Law, do hereby declare the nature of the said Invention for "IMPROVE-
MENTS IN THE CONSTRUCTION AND WORKING OF VOLTAIC BATTERIES," to be as
follows:
-
Our Invention consists in the construction of voltaic couples with a
negative element (which may be either flat or cylindrical in form)

page_text: dividing the cell into two compartments, and pierced or made with
apertures which are filled up with a porous material in such manner as
to allow of the passage of local currents from one surface of the clement
(when this surface becomes "polarized" by the electrolytic liberation of
hydrogen or other electro-positive body) to the other surface (which is
maintained in contact with a fluid or moistened solid capable of oxidizing
nascent hydrogen).
One compartment of the cell contains the positive element of the
couple, and an electrolyte with which this element and ono surface of
the negative element (preferably of carbon) are in contact, and the other
compartment contains a solution (preferably of potassic dichromate
acidulated with sulphuric and nitric acids) capable of oxidising nascent
hydrogen, and necessarily in contact with the other surface of the
negative element.
When the carbon elements are required to be of large surface we
build them of several pieces or numerous fragments of carbon (preferably
gas carbon), graphite, or coke, these pieces or fragments being in
electrical contact with each other at one or more points, but having
apertures or spaces between them which are filled up with porous
material, by means of which the pieces or fragments may be cemented
or held together.
We also use in certain cases for exciting the negative element of
batteries constructed as above (or of other forms of battery in which
carbon is used as the negative element), the insoluble chromates of lime,
baryta, and chromium, which may be mixed with sulphuric acid, or with
a mixture of sulphuric and nitric acids in suitable proportions.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Desmond Gerald Fitz-Gerald and Bernard Charles
Molloy in the Great Seal Patent Office on the 13th December 1873.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, DESMOND 3
GERALD FITZ-GERALD, of 6, Loughborough Road North, in the County
of Surrey, Electrician, and BERNARD CHARLES MOLLOY, of 1, Elm
Court, Temple, in the County of Middlesex, Barrister-at-Law, send
greeting.

page_text: WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Thirteenth day of June, 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 us, the said Desmond Gerald Fitz-Gerald and
Bernard Charles Molloy, Her special license that we, the said Desmond
Gerald Fitz-Gerald and Bernard Charles Molloy, our executors, admini-
strators, and assigns, or such others as we, the said Desmond Gerald
Fitz-Gerald and Bernard Charles Molloy, our 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 THE CONSTRUCTION AND WORKING
OF VOLTAIC BATTERIES," upon the condition (amongst others) that we, the
said Desmond Gerald Fitz-Gerald and Bernard Charles Molloy, our
exccutors or administrators, by an instrument in writing under our or
their hands and seals, or under the hand and seal of one of us or them,
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

page_text: One compartment of the cell contains the positive element of the
couple, and an electrolyte with which this clement and one surface of
the negative element (which is preferably of carbon) are in contact.
The other compartment contains a solution or a mixture of solid and
fluid ingredients capable of oxidising nascent hydrogen, and necessarily
in contact with the other surface of the negative element.
We give the following as examples of this mode of construction. We
take a rectangular or elliptical shaped jar or vessel of glass, earthenware,
or any other suitable material, and preferably made with a groove down
two of the sides (or elliptical surfaces), and along the bottom within the
cell, the said groove being for the purpose of receiving the plate which is
to divide the cell into two compartments. We take also a plate of
carbon (preferably "gas carbon"), of such size as to project slightly
above the top of the cell whilst dividing the latter into two compartments
in the direction of its greater width or otherwise. This plate of carbon
is perforated with apertures or holes, the size and number of which
should be varied proportionately to the intensity of the current which the
cell is required to transmit, and these apertures are filled up with Paris
plaster, pipe clay, or kaolin (baked or otherwise), plugs of asbestos, or
other suitable porous material. The plate is inserted or maintained in
its position across the cell into which it may now be cemented, either by
pouring a little plaster into the bottom of the cell, and subsequently
along the lateral surfaces of junction of the cell and carbon plate, or by
the use of any cement (such as those containing a large proportion of
paraffin wax) which is not readily acted upon by acids and oxidants.
Or to form a hollow negative element of cylindrical or polygonal form,
we take any number of rods or narrow plates, preferably of gas carbon,
and arrange them with a small interval between each rod or plate
longitudinally around the axis of a cylinder or prism (of wood or metal),
with their ends projecting beyond it. In this position they may be
maintained by binding them with wire or twine, whilst by means of a
suitable mould a ring of lead or other metal is cast upon the projecting
ends of the rods or plates in such manner as to bring them into clectrical
contact with each other whilst holding them securely in position. A
binding screw having been secured to the ring of metal the interstices
between the rods or plates are now filled up with Paris plaster or other
suitable porous material, an operation which is best effected by means
of a suitable mould. The cylinder thus formed may be placed con-

page_text: centrically within a suitable cylindrical jar or vessel and made to divide
the latter into two compartments simply by pouring a little Paris plaster
or suitable cement into the bottom of such jar or vessel. The positive
(zinc) clement and a suitable electrolyte are placed within the central
compartment, whilst the outer compartment contains the solution or
mixture of solid and fluid ingredients used to obviate the "polarisation
of the negative (carbon) element.
""
The lower end of the cylinder constituting the central compartment
may if preferred be closed with plaster (saturated with paraffin or
otherwise), or any other suitable material, so as to allow of its removal
from the containing vessel. Or if preferred a carbon element so con-
structed may be used in conjunction with a central porous vessel
containing the positive element, the interstices between the rods or
plates being in this case left open. A ring composed wholly or in part
of metal and made with apertures or slots into which the rods or plates
of carbon are inserted (being held in position by binding screws or
otherwise) may be substituted for the ring of cast metal.
When the carbon elements are required to be of large surface we
build them of several pieces or numerous fragments of carbon (gas
carbon, graphite, or coke), these pieces or fragments being in electrical
contact with each other, but having apertures or spaces between them,
which are filled up with porous material, by means of which the pieces
or fragments are cemented or held together. This porous material may
be Paris plaster or clay baked in a closed vessel with powdered charcoal
or otherwise so as to exclude the air. Such "carbon diaphragm
batteries, depolarised by local currents are adapted either for experi-
mental and telegraphic purposes, or for use on a large scale in manu-
facturing operations.
"
The second part of our Invention relates to the mode of advantageously
working batteries of the above-mentioned construction, and also to
improvements in the means of working certain other batteries con-
structed on the ordinary principle, that is to say, in which the "exciting
fluid" of the negative element is in contact with both of its surfaces.
The object of constructing voltaic cells according to our Invention
in two compartments, which may be conveniently termed the positive
(zinc) and negative (oxygen) compartments is whilst dispensing with
a porous vessel, and thus removing from the circuit the resistance it

page_text: offers to the passage of the current, to obviate the "polarisation" of the
negative element by means of local currents resulting in the oxidation of
hydrogen. These currents induced by the presence of a powerful
oxidant in contact with one of the surfaces of the negative element pass
from the initially polarised carbon surface in the positive compartment
through the electrolyte contained in the porous material, which closes
the apertures in the negative element to the carbon surface in the
negative compartment, completing the local circuit through the
substance of the carbon. This arrangement allows of the use not only
of powerfully corrosive but also of highly crystallisable oxidising
compounds; the zinc element and the effective carbon surface immersed
in a suitable electrolyte being protected from their effect.
Thus a
mixture of nitrate of potash, of soda, and sulphuric acid might be used
in the negative compartment without any ill results from corrosion of
the zinc element by local action or from the deposition of crystals upon
one or both of the surfaces constituting the anode and cathode within
the cell. But we prefer to use a salt, such, for instance as the bichro-
mate of potash, which may with greater advantage and convenience be
deoxidised in the negative compartment. We mix one equivalent of
bichromate of potash in warm saturated solution, with four equivalents
of sulphuric acid, and charge with this mixture the negative compart-
ment of the cell; the positive compartment being charged with dilute
sulphuric acid, solution of sal-ammoniac, or of common salt, or other
suitable electrolyte. Chrome alum is formed in the negative compart-
ment, according to the equation :
--

page_text: In the latter case the valuable salt, sulphate of chromium (Or, 3 SO₂)
which is formed exists in solution with sulphate of zinc. In working
the "carbon diaphragm" battery and double fluid carbon batteries of
the ordinary construction this product may be obtained in a condition
of greater or less purity.
3 SO₁₂)
In the latter case the valuable salt, sulphate of chromium (Cr,
which is formed exists in solution with sulphate of zinc.
In working
the "carbon diaphragm" battery and double fluid carbon batteries of
the ordinary construction this product may be obtained in a condition
of greater or less purity.
What we claim as our Invention is
-
1. The construction of voltaic cells having a combined diaphragmı
and negative electrode composed of conducting and porous non-
conducting materials, and "depolarised" by local currents as herein-
before described.
2. The construction in the manner herein-before described of com-
pound carbon elements in the form of a hollow cylinder or prism,
and the use of such elements either as portion of a carbon diaphragm
depolarised by local currents or in batteries of ordinary construction.
3. The use in voltaic batteries of oxidising compounds formed by the
addition of acids to chromate of lime.
In witness whereof, I, the said Desmond Gerald Fitz-Gerald,
have hereunto set my hand and seal, this Twelfth day of
December, in the year of our Lord One thousand eight hundred
and seventy-three.
DESMOND G FITZGERALD
(L..S.)