Improvements in the Manufacture of Sodium and Potassium.
Year: 1890

page_text: Date of Application, 25th Aug., 1890
Complete Specification Left, 16th May, 1891-Accepted, 27th June, 1891
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Sodium and Potassium.
I, HAMILTON YOUNG CASTNER of 115 Cannon Street in the City of London'
Managing Director of the Aluminium Company Limited do hereby declare the
nature of this invention to be as follows:-
This invention relates to a process for the production of sodium or potassium
from caustic soda or potassa without distillation whereby the cost of production is
considerably reduced.
Briefly stated the process may be said to consist in submitting fused caustic
alkali, maintained at a low temperature, to the decomposing action of the electric
current, suitable apparatus being provided for collecting the separated metal.
I am aware that so long ago as 1808 Sir Humphrey Davy electrolized caustic
soda and produced the alkaline metal in a minute quantity, but the method adopted
in such experiment did not enable the metal to be commercially produced and I
believe that prior to my present invention it was not known that only under certain
conditions of temperature could the electrolysis be effected, as I have failed to find
that any process has heretofore been suggested for commercially manufacturing the
alkaline metals either by chemical or electrical means that did not involve the use
of a temperature sufficient to ensure the distillation of the metal. All such
processes are more or less wasteful owing to the loss of material and to the wear
and tear of the apparatus consequent upon the high temperature necessarily
employed.
My experiments have proved that to secure any practical result from the
electrolysis of either caustic soda or potassa it is absolutely necessary that the
temperature be kept as low as possible while ensuring the liquidity of the electrolyte.
At their melting points both caustic soda and caustic potassa while being electrolized
absorb in a degree both the alkaline metal and oxygen and at even slight elevations
of temperature this absorbing power rapidly increases and finally becomes so great
at higher temperature that the products from the electrolysis are absorbed as
rapidly as they are formed and practically no decomposition is obtained. Thus I
have found that in order to attain any practical result such means must be
employed as will ensure a constant and low temperature while at the same time the
elements produced from the decomposition should be given an opportunity of
escaping or being removed from the absorbing power of the electrolyte as quickly
as possible. In carrying out my present invention there is practically no waste or
loss of material, while the wear and tear upon the apparatus is small.
In order that others skilled in the art may fully comprehend my invention
reference is made to the accompanying drawing which represents a sectional
elevation of a convenient form of apparatus for carrying my invention into effect.
Said apparatus consists of an iron vessel or receptacle A suitably mounted
in brickwork R so that the heat applied by the gas burners G may be well
distributed. The vessel A is provided with one or more base pipes or extensions B
adapted to receive the negative electrodes H which are preferably of metal and
pass up into the vessel. Suspended directly above the said cathode is a tubular
iron receptacle or vessel C which is provided on its upper end with a lid N, and to
its lower edges is secured an iron wire gauze M, the said gauze when the
receptacle N is placed in position completely surrounding the cathode.
positive electrodes F are preferably made of such metal as will withstand
the oxidizing action of the evolved gases and either form part of the cover of the
vessel A or may be bolted thereon, being so placed that when the cover is
The

page_text: adjusted the electrodes are a suitable distance from, and directly surround the
gauze M. Electrical connection is made between the cover by the connection I
with the positive pole of the dynamo, and by the connection L with the negative.
The cover is provided with an opening P for the escape of gases resulting from the
electrical action, this opening also serving for the introduction of a thermometer or
other heat registering device. Insulation is made at the points S S, by means of
asbestos or other insulating medium. The size and distance apart of the electrodes
are both proportioned to the quantity of current to be supplied. Should the
electrodes have a larger surface than is actually required the elements set free at
each electrode are exposed to the absorbing alkali to a greater extent than
necessary, and a quantity of the electrical action is wasted owing to the elements
being absorbed and recombining. Should the electrodes be too small the resistance
will be increased to such an extent that the bath will be unduly heated and that at
the very points where an excess of temperature is most objectionable.
If a suitable electric current be passed through the molten caustic soda or
potassa E the alkali being kept at a very low temperature any water contained in
the caustic will be decomposed and resolved into its elements of hydrogen and
oxygen which will be given off at the negative and positive electrodes respectively.
When this action has ceased the current will act upon the caustic alkali, oxygen
or a mixture of oxygen and water being given off at the positive pole, while the
alkaline metal and hydrogen or the alkaline metal alone are given off at the
negative pole.
In the apparatus as described the alkaline metal (being much lighter than the
caustic) together with the hydrogen will rise from the negative electrode and pass
into the receiver C, the hydrogen escaping around the edges of the cover N while
the molten metal continues to collect in quantity. From time to time this collected
metal D is removed by means of a large finely perforated spoon. The perforations
enabling the molten caustic to flow out while the metal remains in the spoon.
Caustic is added to the bath from time to time to replace the metal removed, and
in this manner a continuous process may be carried on without the aid of expensive
plant, and in an economical manner.
As before mentioned any increase of temperature is followed by a proportionate
loss of product and waste of electrical energy, but it is possible to so adjust the electrical
current and the quantity of caustic alkali forming the electrolyte, that the propre
temperature will be maintained in a previously melted bath without external heat or
even by an increase of current to melt the bath, subsequently reducing the quantity
of current, until the working temperature is attained, or if large currents are used
the bath and the electrodes may be artificially cooled by air or water circulation.
The cathode may be conveniently sealed in the extension B by means of molten
caustic K which is allowed to harden before beginning the process.
In order to secure a fair yield, of alkaline metal for the current applied it is
necessary that the temperature of the electrolyte should not be allowed to go
above 20° C. of the respective melting points of the caustic used, viz. in using
caustic soda having a melting point of about 310° C. for the electrolyte the
temperature should be maintained below 330° C. The same rule is to be observed
in respect to the caustic potassa or to a mixture of the two hydrates, the same
having a lower melting point than either the potassa or soda compound alone.
I do not of course confine myself to the particular form of apparatus shown but
simply describe it as one of the forms which may be employed.
Dated the 25th day of August 1890.
PHILIP M. JUSTICE,
55 & 56, Chancery Lane, London, Applicant's Agent,

page_text: COMPLETE SPECIFICATION.
Improvements in the Manufacture of Sodium and Potassium,
I, HAMILTON YOUNG CASTNER of 115 Cannon Street in the City of London,
Managing Director of the Aluminium Company Limited, do hereby declare the
nature of this invention and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement:-
This invention relates to a process for the production of sodium or potassium
from caustic soda or potassa without distillation whereby the cost of production is
considerably reduced.
Briefly stated the process may be said to consist in submitting fused caustic
alkali, maintained at a low temperature, to the decomposing action of the electric
current, suitable apparatus being provided for collecting the separated metal.
I am aware that so long ago as 1808 Sir Humphrey Davy electrolized caustic
soda and produced the alkaline metal in a minute quantity, but the method adopted
in such experiment did not enable the metal to be commercially produced and I
believe that prior to my present invention it was not known that only under certain
conditions of temperature could the electrolysis be effected, as I have failed to find
that any process has heretofore been suggested for commercially manufacturing the
alkaline metals either by chemical or electrical means that did not involve the use
of a temperature sufficient to ensure the distillation of the metal. All such processes
are more or less wasteful owing to the loss of material and to the wear and tear of
the apparatus consequent upon the high temperature necessarily employed.
My experiments have proved that to secure any practical result from
the electrolysis of either caustic soda or potassa it is absolutely necessary that
the temperature be kept as low as possible while ensuring the liquidity of the
electrolyte. At their melting points both caustic soda and caustic potassa while
being electrolized absorb in a degree both the alkaline metal and oxygen and at
even slight elevations of temperature this absorbing power rapidly increases and
finally becomes so. great at higher temperature that the products from the
electrolysis are absorbed as rapidly as they are formed and practically no
decomposition is obtained. Thus I have found that in order to attain any practical
result such means must be employed as will ensure a constant and low temperature
while at the same time the elements produced from the decomposition should be
given an opportunity of escaping or being removed from the absorbing power of
the electrolyte as quickly as possible. In carrying out my present invention there
is practically no waste or loss of material, while the wear and tear upon the
apparatus is small.
In order that others skilled in the art may fully comprehend my invention
reference is made to the accompanying drawing which represents a sectional
elevation of a convenient form of apparatus for carrying my invention into effect.
Said apparatus consists of an iron vessel or receptacle A suitably mounted in
brickwork R so that the heat applied by the gas burners G may be well distributed.
The vessel A is provided with one or more base pipes or extensions B adapted to
receive the negative electrodes H which are preferably of metal and pass up into
the vessel. Suspended directly above the said cathode is a tubular iron receptacle
or vessel C which is provided on its upper end with a lid N, and to its lower edges
is secured an iron wire gauze M, the said gauze when the receptacle N is placed in
position completely surrounding the cathode. The positive electrodes F are
preferably made of such metal as will withstand the oxidizing action of the evolved
gases and either form part of the cover of the vessel A or may be bolted thereon,
being so placed that when the cover is adjusted the electrodes are a suitable
distance from, and directly surround the gauze M. Electrical connection is made
between the cover by the connection I with the positive pole of the dynamo, and by
the connection L with the negative. The cover is provided with an opening P for

page_text: the escape of gases resulting from the electrical action, this opening also serving
for the introduction of a thermometer or other heat registering device. Insulation
is made at the points S S, by means of asbestos or other insulating medium. The
size and distance apart of the electrodes are both proportioned to the quantity of
current to be supplied. Should the electrodes have a larger surface than is actually
required the elements set free at each electrode are exposed to the absorbing alkali
to a greater extent than necessary, and a quantity of the electrical action is wasted
owing to the elements being absorbed and recombining. Should the electrodes be
too small the resistance will be increased to such an extent that the bath will be
unduly heated and that at the very points where an excess of temperature is most
objectionable.
If a suitable electric current be passed through the molten caustic soda or
potassa E the alkali being kept at a very low temperature any water contained in
the caustic will be decomposed and resolved into its elements of hydrogen and
oxygen which will be given off at the negative and positive electrodes respectively.
When this action has ceased the current will act upon the caustic alkali, oxygen or
a mixture of oxygen and water being given off at the positive pole, while the
alkaline metal and hydrogen or the alkaline metal alone are given off at the
negative pole.
In the apparatus as described the alkaline metal (being much lighter than the
caustic) together with the hydrogen will rise from the negative electrode and pass
into the receiver C, the hydrogen escaping around the edges of the cover N while
the molten metal continues to collect in quantity. From time to time this collected
metal D is removed by means of a large finely perforated spoon. The perforations
enabling the molten caustic to flow out while the metal remains in the spoon.
Caustic is added to the bath from time to time to replace the metal removed, and
in this manner a continuous process may be carried on without the aid of expensive
plant, and in an economical manner.
As before mentioned any increase of temperature is followed by a proportionate
loss of product and waste of electrical energy, but it is possible to so adjust the
electrical current and the quantity of caustic alkali forming the electrolyte, that
the proper temperature will be maintained in a previously melted bath without
external heat or even by an increase of current to melt the bath, subsequently
reducing the quantity of current, until the working temperature is attained, or if
large currents are used the bath and the electrodes may be artificially cooled by air
or water circulation.
The cathode may be conveniently sealed in the extension B by means of molten
caustic K which is allowed to harden before beginning the process.
In order to secure a fair yield of alkaline metal for the current applied it is
necessary that the temperature of the electrolyte should not be allowed to go
above 20° C. of the respective melting points of the caustic used, viz. in using
caustic soda having a melting point of about 310° C. for the electrolyte the
temperature should be maintained below 330° C. The same rule is to be observed
in respect to the caustic potassa or to a mixture of the two hydrates, the same
having a lower melting point than either the potassa or soda compound alone.
I do not of course confine myself to the particular form of apparatus shown but
simply describe it as one of the forms which may be employed.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is
1. The hereinbefore described process of manufacturing the alkaline metals,
which consists in treating the caustic alkali while constantly maintained at a
temperature of not more than 20° C. above its melting point to the action of the
electric current substantially as described.
2. The hereinbefore described process of manufacturing the alkaline metals which
consists in submitting the caustic alkali to the action of the electric current, said

page_text: alkali being kept at such a low temperature that the metal may be separated but
not distilled, substantially as described.
3. In apparatus for carrying out the process described in the foregoing claims
the combination with the two electrodes of an interposed screen or gauze and a vessel
adapted to receive the reduced metal, the surface area of the electrodes and their
distance apart being proportioned to the quantity of current employed so that the
bath may be kept at a constant temperature.
Dated this 15th day of May 1891.
PHILIP M. JUSTICE,
55 & 56, Chancery Lane, London, Applicant's Agent.

page_text: Date of Application, 25th Aug., 1890
Complete Specification Left, 16th May, 1891-Accepted, 27th June, 1891.
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Sodium and Potassium.
I, HAMILTON YOUNG CASTNER of 115 Cannon Street in the City of London,
Managing Director of the Aluminium Company Limited do hereby declare the
nature of this invention to be as follows:-
This invention relates to a process for the production of sodium or potassium
from caustic soda or potassa without distillation whereby the cost of production is
considerably reduced.
Briefly stated the process may be said to consist in submitting fused caustic
alkali, maintained at a low temperature, to the decomposing action of the electric
current, suitable apparatus being provided for collecting the separated metal.
I am aware that so long ago as 1808 Sir Humphrey Davy electrolized caustic
soda and produced the alkaline metal in a minute quantity, but the method adopted
in such experiment did not enable the metal to be commercially produced and I
believe that prior to my present invention it was not known that only under certain
conditions of temperature could the electrolysis be effected, as I have failed to find
that any process has heretofore been suggested for commercially manufacturing the
alkaline metals either by chemical or electrical means that did not involve the use
of a temperature sufficient to ensure the distillation of the metal. All such
processes are more or less wasteful owing to the loss of material and to the wear
and tear of the apparatus consequent upon the high temperature necessarily
employed.
My experiments have proved that to secure any practical result from the
electrolysis of either caustic soda or potassa it is absolutely necessary that the
temperature be kept as low as possible while ensuring the liquidity of the electrolyte.
At their melting points both caustic soda and caustic potassa while being electrolized
absorb in a degree both the alkaline metal and oxygen and at even slight elevations
of temperature this absorbing power rapidly increases and finally becomes so great
at high temperature that the products from the electrolysis are absorbed as
rapidly as they are formed and practically no decomposition is obtained. Thus I
have found that in order to attain any practical result such means must be
employed as will ensure a constant and low temperature while at the same time the
eleinents produced from the decomposition should be given an opportunity of
escaping or being removed from the absorbing power of the electrolyte as quickly
as possible. In carrying out my present invention there is practically no waste or
loss of material, while the wear and tear upon the apparatus is small.
In order that others skilled in the art may fully comprehend my invention
reference is made to the accompanying drawing which represents a sectional
elevation of a convenient form of apparatus for car ying my invention into effect.
Said apparatus consists of an iron vessel or receptacle A suitably mounted
in brickwork R so that the heat applied by the gas burners G may be well,
distributed. The vessel A is provided with one or more base pipes or extensions B
adapted to receive the negative electrodes H which are preferably of metal and
pass up into the vessel. Suspended directly above the said cathode is a tubular
iron receptacle or vessel C which is provided on its upper end with a lid N, and to
its lower edges is secured an iron wire gauze M, the said gauze when the
receptacle N is placed in position completely surrounding the cathode. The
positive electrodes F are preferably made of such metal as will withstand
the oxidizing action of the evolved gases and either form part of the cover of the
vessel A or may be bolted thereon, being so placed that when the cover is

page_text: adjusted the electrodes are a suitable distance from, and directly surround the
gauze M. Electrical connection, is made between the cover by the connection I
with the positive pole of the dynamo, and by the connection L with the negative.
The cover is provided with an opening P for the escape of gases resulting from the.
electrical action, this opening also serving for the introduction of a thermometer or
-other heat registering device. Insulation is made at the points S S, by means of
asbestos or other insulating medium. The size and distance apart of the electrodes
are both proportioned to the quantity of current to be supplied. Should the
electrodes have a larger surface than is actually required the elements set free at
each electrode are exposed to the absorbing alkali to a greater extent-than
necessary, and a quantity of the electrical action is wasted owing to the elements
being obsorbed and recombining. Should the electrodes be too small the resistance
will be increased to such an extent that the bath will be unduly heated and that at
the very points where an excess of temperature is most objectionable.
If a suitable electric current be passed through the molten caustic soda or
potassa E the alkali being kept at a very low temperature any water contained in
the caustic will be decomposed and resolved into its elements of hydrogen and
oxygen which will be given off at the negative and positive electrodes respectively.
When this action has ceased the current will act upon the caustic alkali, oxygen
or a mixture of oxygen and water being given off at the positive pole, while the
alkaline metal and hydrogen or the alkaline metal alone are given off at the
negative pole.
In the apparatus as described the alkaline metal (being much lighter than the
caustic) together with the hydrogen will rise from the negative electrode and pass
into the receiver C, the hydrogen escaping around the edges of the cover N while
the molten metal continues to collect in quantity. From time to time this collected
metal D is removed by means of a large finely perforated spoon. The perforations
enabling the molten caustic to flow out while the metal remains in the spoon.
Caustic is added to the bath from time to time to replace the metal removed, and
in this manner a continuous process may be carried on without the aid of expensive
plant, and in an economical manner.
As before mentioned any increase of temperature is followed by a proportionate
loss of product and waste of electrical energy, but it is possible to so adjust the electrical
current and the quantity of caustic alkali forming the electrolyte, that the proper
temperature will be maintained in a previously melted bath without external heat or
even by an increase of current to melt the bath, subsequently reducing the quantity
of current, until the working temperature is attained, or if large currents are used
the bath and the electrodes may be artificially cooled by air or water circulation.
The cathode may be conveniently sealed in the extension B by means of inolten
caustic K which is allowed to harden before beginning the process.
In order to secure a fair yield of alkaline metal for the current applied it is
necessary that the temperature of the electrolyte should not be allowed to go
above 20° C. of the respective melting points of the caustic used, viz. in using
caustic soda having a melting point of about 310° C. for the electrolyte the
temperature should be maintained below 330° C. The same rule is to be observed
in respect to the caustic potassa or to a mixture of the two hydrates, the same
having a lower melting point than either the potassa or soda compound alone.
I do not of course confine myself to the particular form of apparatus shown but
simply describe it as one of the forms which may be employed.
Dated the with day of Au 1000
PHILLIP M. JUSTICE,
55 & 56, Chancery Lane, London, Applicant's Agent.

page_text: Improvements in the Manufacture of Sodium and Potassium.
I, HAMILTON YOUNG CASTNER of 115 Cannon Street in the City of London,
Managing Director of the Aluminium Company Limited, do hereby declare the
nature of this invention and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement:-
This invention relates to a process for the production of sodium or potassium
from caustic soda or potassa without distillation whereby the cost of production is
considerably reduced.
Briefly stated the process may be said to consist in submitting fused caustic
alkali, maintained at a low temperature, to the decomposing action of the electric
current, suitable apparatus being provided for collecting the separated metal.
I am aware that so long ago as 1808 Sir Humphrey Davy electrolized caustic
soda and produced the alkaline metal in a minute quantity, but the method adopted
in such experiment did not enable the metal to be commercially produced and I
believe that prior to my present invention it was not known that only under certain
conditions of temperature could the electrolysis be effected, as I have failed to find
that any process has heretofore been suggested for commercially manufacturing the
alkaline metals either by chemical or electrical means that did not involve the use
of a temperature sufficient to ensure the distillation of the metal. All such processes
are more or less wasteful owing to the loss of material and to the wear and tear of
the apparatus consequent upon the high temperature necessarily employed.
My experiments have proved that to secure any practical result from
the electrolysis of either caustic soda or potassa it is absolutely necessary that
the temperature be kept as low as possible while ensuring the liquidity of the
electrolyte. At their melting points both caustic soda and caustic potassa while
being electrolized absorb in a degree both the alkaline metal and oxygen and at
even slight elevations of temperature this absorbing power rapidly increases and
finally becomes so great at higher temperature that the products from the
electrolysis are absorbed as rapidly as they are formed and practically no
decomposition is obtained. Thus I have found that in order to attain any practical
result such means must be employed as will ensure a constant and low temperature
while at the same time the elements produced from the decomposition should be
given an opportunity of escaping or being removed from the absorbing power of
the electrolyte as quickly as possible. In carrying out my present invention there
is practically no waste or loss of material, while the wear and tear upon the
apparatus is small.
In order that others skilled in the art may fully comprehend my invention
reference is made to the accompanying drawing which represents a sectional
elevation of a convenient form of apparatus for carrying my invention into effect.
Said apparatus consists of an iron vessel or receptacle A suitably mounted in
brickwork R so that the heat applied by the gas burners G may be well distributed.
The vessel A is provided with one or more base pipes or extensions B adapted to
receive the negative electrodes H which are preferably of metal and pass up into
the vessel. Suspended directly above the said cathode is a tubular iron receptacle
or vessel C which is provided on its upper end with a lid N, and to its lower edges
is secured an iron wire gauze M, the said gauze when the receptacle N is placed in
position completely surrounding the cathode. The positive electrodes F are
preferably made of such metal as will withstand the oxidizing action of the evolved
gases and either form part of the cover of the vessel A or may be bolted thereon;
being so placed that when the cover is adjusted the electrodes are a suitable
distance from, and directly surround the gauze M. Electrical connection is made
between the cover by the connection I with the positive pole of the dynamo, and by
the connection L with the negative. The cover is provided with an opening P for

page_text: the escape of gases resulting from the electrical action, this opening also serving
for the introduction of a thermometer or other heat registering device. Insulation
is made at the points SS, by means of asbestos or other insulating medium. The
size and distance apart of the electrodes are both proportioned to the quantity of
current to be supplied. Should the electrodes have a larger surface than is actually
required the elements set free at each electrode are exposed to the absorbing alkali.
to a greater extent than necessary, and a quantity of the electrical action is wasted
owing to the elements being absorbed and recombining. Should the electrodes be
too small the resistance will be increased to such an extent that the bath will be
unduly heated and that at the very points where an excess of temperature is most
objectionable.
"
If a suitable electric current be passed through the molten caustic soda or
potassa E the alkali being kept at a very low temperature any water contained in
the caustic will be decomposed and resolved into its elements of hydrogen and
oxygen which will be given off at the negative and positive electrodes respectively.
When this action has ceased the current will act upon the caustic alkali, oxygen or.
a mixture of oxygen and water being given off at the positive pole, while the
alkaline metal and hydrogen or the alkaline metal alone are given off at the
negative pole.
In the apparatus as described the alkaline metal (being much lighter than the
caustic) together with the hydrogen will rise from the negative electrode and pass
into the receiver C, the hydrogen escaping around the edges of the cover N while
the molten metal continues to collect in quantity. From time to time this collected
metal D is removed by means of a large finely perforated spoon. The perforations
enabling the molten caustic to flow out while the metal remains in the spoon.
Caustic is added to the bath from time to time to replace the metal removed, and
in this manner a continuous process may be carried on without the aid of expensive
plant, and in an economical manner.
As before mentioned any increase of temperature is followed by a proportionate
loss of product and waste of electrical energy, but it is possible to so adjust the
electrical current and the quantity of caustic alkali forming the electrolyte, that
the proper temperature will be maintained in a previously melted bath without
external heat or even by an increase of current to melt the bath, subsequently
reducing the quantity of current, until the working temperature is attained, or if
large currents are used the bath and the electrodes may be artificially cooled by air
or water circulation.
The cathode may be conveniently sealed in the extension B by means of molten
caustic K which is allowed to harden before beginning the process.
In order to secure a fair yield of alkaline metal for the current applied it is
necessary that the temperature of the electrolyte should not be allowed to go
above 20° C. of the respective melting points of the caustic used, viz. in using
caustic soda having a melting point of about 3.10° C. for the electrolyte the
temperature should be maintained below 330° C. The same rule is to be observed
in respect to the caustic potassa or to a mixture of the two hydrates, the same
having a lower melting point than either the potassa or soda compound alone.
I do not of course confine myself to the particular form of apparatus shown but
simply describe it as one of the forms which may be employed.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is:-
1. The hereinbefore described process of manufacturing the alkaline metals,
which consists in treating the caustic alkali while constantly maintained at a
temperature of not more than 20° C. above its melting point to the action of the
electric current substantially as described..
2. The hereinbefore described process of manufacturing the alkaline metals which
Bonsists in submitting the caustic alkali to the action of the electric current, said

page_text: alkali being kept at such a low temperature that the metal may be separated but
not distilled, substantially as described.
3. In apparatus for carrying out the process described in the foregoing claims
the combination with the two electrodes of an interposed screen or gauze and a vessel
adapted to receive the reduced metal, the surface area of the electrodes and their
distance apart being proportioned to the quantity of current employed so that the
bath may be kept at a constant temperature.
PHILIP M. JUSTICE,
55 & 56, Chancery Lane, London, Applicant's Agent.