IMPROVEMENTS IN OBTAINING LIGHT BY ELECTRICITY, AND IN CONVEYING, DISTRIBUTING, MEASURING, AND REGU- LATING THE ELECTRIC CURRENT FOR THE SAME, AND IN THE MEANS OR APPA- RATUS EMPLOYED THEREIN
Year: 1878

page_text: LETTERS PATENT to St. George Lane Fox, of Telegraph Street, in the City of
London, for the Invention of "IMPROVEMENTS IN OBTAINING LIGHT BY
ELECTRICITY, AND IN CONVEYING, DISTRIBUTING, MEASURING, AND REGU-
LATING THE ELECTRIC CURRENT FOR THE SAME, AND IN THE MEANS OR APPA-
RATUS EMPLOYED THEREIN."
Sealed the 13th December 1878, and dated the 9th Octber 1878.
PROVISIONAL SPECIFICATION left by the said St. George Lane Fox
"
at the Office of the Commissioners of Patents on the 9th October 1878.
ST. GEORGE LANE Fox, of Telegraph Street, in the City of London. IMPROVE
MENTS IN OBTAINING LIGHT BY ELECTRICITY, AND IN CONVEYING, DISTRIBUTING,
MEASURING, AND REGULATING THE ELECTRIC CURRENT FOR THE SAME, AND IN THE
MEANS OR APPARATUS EMPLOYED THEREIN."
My Invention consists of improvements in obtaining light by electricity, and in
conveying, distributing, measuring, and regulating the electric current for the same,
and in the means or apparatus employed therein.
In order to produce a light I pass the electric current through thin leaves or foil
of some suitable material, for which purpose I prefer to use platinum or an alloy of
platinum and iridium.
The electric lamp in which the light is produced therefore consists of two con-
ductors, insulated from one another, having this leaf or foil stretched between them
and in contact with each. On each side of this leaf or foil I place a sheet of trans-
parent mica or tale to prevent as much as possible radiation of heat from the surfaces
and the cooling of the leaf or foil from atmospheric action; the sheets of mica or talc
can be covered with glass plates.
Instead of stretching a strip of leaf or foil between two conductors, as already
described, I sometimes coil a long strip of foil into a kind of spiral shape having a
tube of talc, glass, fire-clay, steatite, or lime within the spiral, and one of talc or

page_text: glass just covering it outside; a fine platinum wire may be used instead of a strip
of foil, but the foil is preferable. A chief object I wish to attain in this lamp is to
prevent as much as possible the dissipation of force in the form of heat and to con-
centrate and intensify it in the form of light.
An increase of light is attained by increasing the width or number of strips or by
diminishing their length; in the first place more volume of light will be attained,
in the second the light will be intensified.
Care should be taken that the length of the strips of foil is not too short and
that they should not be too fiue, otherwise there is a risk of fusing them; their
length and width must be fixed according to the intensity and quantity of light
required and of the electro-motive force used.
The way in which I work a number of these lamps from a single source of elec-
tricity is as follows:-From one pole or electrode of the electric generator or
generators proceeds, a large conductor from which branch out at various points
where lights are desired smaller conductors which again may have conductors
branching off from them, and so on. The other pole or electrode of each electric
generator is connected with the earth, so that the conductor and its branches and
sub-branches will be perpetually in a state of electric tension tending to develope
currents in every direction to the earth.
One pole of the electric lamp is connected with the earth, and this may be con-
veniently effected by means of gas or water pipes where such exist, so that wherever
the circuit is complete between the earth and any one of these branches a current
of electricity will pass through the thin leaf of metal rendering it incandescent and
so produce light. The method by which I measure the amount of electricity used
is as follows: I shunt off from any given length of the conductor (the amount of
electricity passing through which is to be ascertained) a "derived "circuit having
a voltameter joined up in it. The resistance of this circuit must be very much
greater than that of the length of conductor from which is has been shunted.
The resistance of both voltameter and conductor being fixed the quantity of
electricity passing through the voltameter will consequently bear a fixed ratio to
the amount passing through the conductor. In this manner with a graduated tube
the height of a column of liquid can be measured and so the quantity of electricity
passed can be ascertained.
The electro-motive force of the electric conducting mains should be kept as
nearly as possible constant at, say, 100 volts or British Association units of electro-
motive force.
A number of Plante's (lead and sulphuric acid) cells joined together in series
between the main and the earth will serve as a kind of reservoir for the electricity.
The electric current may be conducted through copper conductors which can con-
veniently be laid inside the existing gas pipes having insulators of earthenware or
other material around them to prevent their contact with the iron pipes. The con-
ducting mains may be formed of a number of copper bands. soldered together at the
joints and insulated as just described. A very high degree of insulation can be
obtained by filling the annular space between the copper conductors and the iron
pipes with some insulating liquid, preferably petroleum rock oil. In order to keep
the electro-motive force in the electric mains constant it is desirable to have in the
first place several generating machines, next, it is necessary to have some regulator
such as that about to be described. In my regulator I make use of what is known
as the quadrant electro-meter; in this instrument the position of the suspended
needle will depend on the relative electro-motive force of the so-called quadrants.
By connecting this instrument with the main and the earth in the ordinary way
the electro-motive force of the main will determine the position of the suspended
needle; if it increase or decrease the position of the needle will be altered accord-
ingly. Now I fit this electro-meter with small pegs so that a slight deviation of
the needle one way or the other will bring it in contact with one of the pegs and
thus complete a circuit and set up the electric current which acting upon an electro-
magnet sets a lever, or other suitable device in action. The contact with each peg

page_text: forms a separate circuit acting independently on two of these levers or other devices
which are in connection with steam valves, one diminishing the other increasing the
supply of steam to the engine which works the electric generators. The electro-
motive force can be regulated either in this manner or by otherwise effecting the
action of the electric generators through the instrumentality of the currents set
up by the pegs above described so as to increase or diminish the action of the
generators.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said St. George Lane Fox in the Great Seal Patent Office on the 9th
April 1879.
"IMPROVE-
ST. GEORGE LANE Fox, of Telegraph Street, in the City of London.
MENTS IN OBTAINING LIGHT BY ELECTRICITY, AND IN CONVEYING, DISTRIBUTING,
MEASURING, AND REGULATING THE ELECTRIC CURRENT FOR THE SAME, AND IN THE
MEANS OR APPARATUS EMPLOYED THEREIN."
My Invention consists of improvements in obtaining light by electricity, and in
conveying, distributing, measuring, and regulating the electric current for the same,
and in the means or apparatus employed therein.
In order to produce a light I pass the electric current through a thin strip or
wire of some suitable material, for which purpose I prefer to use an alloy of platinum
and iridium. The electric lamp in which the light is produced therefore consists of
two conductors insulated from one another, having this strip or wire between them
and in contact with each.
The material or alloy employed should be capable of standing as high a degree of
temperature as possible without fusing, volatilizing, or falling to pieces; it should
also have a high specific resistance. The higher the temperature to which the
material can be raised the more economical will be the light produced, that is,
the light will be greater in proportion to the force or energy expended, inas-
much as the radiant energy proceeding from the surface of the material will be
more and more luminous as the temperature increases. In order to prevent the
deterioration of the material when incandescent, I sometimes surround it with
an atmosphere of nitrogen gas. The quantity of light will be proportional to
the extent of the luminous surface. The resistance of the luminous material and
its extent of surface should therefore depend on the amount of light it is required to
give and the electro-motive force used. Speaking broadly, it may be said that the
resistance of the luminous conductor should be so adjusted or fixed that the electro-
motive force of the mains to which it is attached is just sufficient to develop within
it the strength of current necessary to raise it to the right degree of incandescence.
. In order that the electric force may be conveyed at a high tension, that is, having
high electro-motive force, so that there may not be very great loss from the
resistance of the conducting mains or conductors, I make the lamps when I use an
alloy of platinum and iridium of lengths of fine wires, so that I may get a high

page_text: resistance without having a large extent of luminous surface. I generally suspend
the wire as shewn in Figures 1 and 2 of the annexed Drawings, as I find that at a
high state of incandescence the alloy becomes soft, and would not retain its shape if
coiled or otherwise twisted.
In Figure 1 a represents the wire of alloy of platinum and iridium; it is
suspended between the two conductors b, b, which pass through the top c of the
lamp; d is a cover of glass or other suitable material cemented or hermetically
sealed to the top c. In Figure 2 the wire a is shewn as passing several times over
a bar or tube e of glass or other insulating material, the ends of the wire being
attached as before to the two conductors b, b.
The way in which I distribute the electric energy so as to work a number of
these lamps from a single source of electricity is represented in the diagrams,
Figures 3 and 5, and is as follows:-From one pole or electrode of the electric
generator or generators (situated at A, Figure 3) proceed one or more large con-
ductors, from which branch out at various points where lights are desired smaller
conductors, which again may have conductors branching off from them, and so on.
The other pole or electrode of cach electric generator is connected with the earth,
so that the conductor and its branches and sub-branches will be perpetually in a
state of electric tension tending to develop currents in every direction to the earth.
One pole of the electric lamp is connected with the earth e, and this may be con-
veniently effected by means of gas or water pipes where such exist, so that wherever
the circuit is complete between the lamp and any one of these branches a current of
electricity will pass through the thin strip or wire, rendering it incandescent, and so
produce light.
=
The way in which I measure the quantity of electric force or energy used is as
follows I shunt off from any given length or resistance of the conductor (the
quantity of electricity passing through which it is desired to ascertain) a "derived
circuit," having an elecro-magnetic voltameter joined up in it; the resistance of
this electro-magnetic voltameter should be much greater than the portion of the
conductor from which it has been shunted..
Figure 4 represents the electro-magnetic voltameter. a, al, is a portion of the
conductor; b, 61, 61, is a derived circuit in which is the coil of an electro-magnet c.
In conjunction with this electro-magnet is an automatic make-and-break pieco kc.
A voltameter v is joined between the set screw 7 and the hammer h, or between the
points where the contact is made and broken.
The action of the apparatus is as follows:-When a current passes through the
conductor a, a¹, there will necessarily be a difference of electro-motive force between
the points a and a¹, the result of which will be that an electric current will be made
to circulate through the coil c and magnetize the soft-iron core. The hammer h,
which is attached to a spring, will thus be drawn out of its normal position and
break the contact at between the set screw and the hammer h. The hammer
will then no longer be attracted, and will fall back to its original position and
re-establish the contact, and so on. The voltameter vis, as already stated, joined
up between the points of contact. The extra current formed on breaking contact will
pass through the voltameter and decompose the water it contains; the quantity of
water decomposed will be approximately proportional to the quantity of electricity
which has passed through the conductor a, a¹.
The electro-motive force of the electric conducting mains should be kept as
nearly as possible constant at, say, 100 volts or British Association units of electro-
motive force.
A number of secondary batteries, such as Plante's (lead and sulphuric acid), or
those formed with plates of copper in a solution of bicarbonate of soda, such
batteries being joined together in series between the main and the earth, will serve
as a kind of reservoir for the electricity. The cells should have a very large con-
ducting surface, and there should be several batteries connected up at various points
of the mains, so that by increasing the electro-motive force during the hours when
not much electricity is being used they will become charged and the electric force

page_text: will be stored up in them, so that a sufficient supply will be available when the
electro-motive force falls owing to the draft from the mains when the force is most
used and needed. The number of cells in each of these batteries will depend on the
electro-motive force of the mains.
Figure 5 is a diagram representing a secondary battery joined up between the
main and the earth for the purpose above described. E indicates earth and lamps.
The electric current may be conveyed through copper conductors which can
conveniently be laid inside the existing gas pipes with insulators of earthenware or
other material of annular or other suitable form around them to prevent their
contact with the iron pipes. The conducting mains may be formed of a number of
copper bands soldered together at the joints and insulated as just described.
I sometimes fill the space between the copper conductor and the iron pipes with
some insulating liquid, preferably petroleum or rock oil, by which means a very high
degree of insulation can be obtained. In order to keep the electro motive force in
the electric mains constant, it is desirable to have in the first place several generating
machines, also a number of reservoir batteries as before explained, next it is necessay
to have some regulator such as that about to be described. In my regulator I
make use of what is known as the quadrant electro-meter; in this instrument the
position of the suspended needle will depend on the relative electro-motive force of
the so-called quadrants. By connecting this instrument with the main and the
earth in the ordinary way, the electro-motive force of the main will determine the
position of the supended needle. If it increase or decrease the position of the
needle will be altered accordingly. Now I fit this electro-meter with small pegs so
that a slight deviation of the needle one way or the other will bring it in contact
with one of these pegs and thus complete a circuit and set up the electric current
which acting upon an electro-magnet sets a lever or other suitable device in action.
The contact with each peg forms a separate circuit acting independently on two of
these levers or other devices which are in connection with steam valves, one
diminishing the other increasing the supply of steam to the engine which works
the electric generators. The electro-motive force can be regulated cither in this
manner or by otherwise effecting the action of the electric generators through the
instrumentality of the currents set up by the pegs above described, so as to increase
or diminish the action of the generators.
the
Figure 6 represents a quadrant electro-meter adapted to regulating the electro
motive force in the mains as just described. a, a are the quadrants and
suspended needle; c, c, are pegs of platinum or other suitable material; and d, d,
are springs situated between the needle band these pegs; e is the wire connecting
with the the main, and f that connecting with the earth; y, g represent electro-
magnets in connection with the respective pegs c, c, the said magnets acting on
levers or other devices for operating the steam valves as above described.
And having now described the nature of my said Invention and in what manner
the same is to be performed, I declare that I claim as my "Improvements in
obtaining Light by Electricity, and in Conveying, Distributing, Measuring, and
Regulating the Electric Current for the same, and in the Means or Apparatus em-
ployed therein."
First. The mode or system herein before described of distributing the electric
current by mains, branches, and sub-branches, with returns by "earth."
Second. In combination with the said mode or system of distributing the electric
current by mains, branches, and sub-branches with returns by "carth," I claim the
production of light by the incandescence of a continuous conductor as herein-before
described.
Third. The means or apparatus substantially as herein-before described with
reference to Figure 4 for measuring the amount of electricity passed through
conductors.
Fourth. The employment as described of secondary batteries as reservoirs of
electricity in combination with a mode or system of distribution such as is herein-
before explained.

page_text: Fifth. The employment of petroleum or rock oil or other suitable insulating liquid
in the space between the conductors and the pipes in which they are laid, as herein-
before described.
Sixth. Constructing apparatus substantially as herein-before described and
represented in Figure 6 for regulating the electro-motive force in the mains by
which the electricity is conveyed.
Seventh. The combination of the means or apparatus herein-before described
for obtaining light by electricity, and conveying, distributing, regulating, and
measuring the electric current for the same.
Eighth. Obtaining light by the incandescence of a continuous conductor, as herein-
before described and as represented in Figures 1 and 2 of the annexed Drawings.
Ninth. Insulating the conductors for conveying electricity for lighting purposes
by means of earthenware or other insulating supports in pipes, as herein-before
described.
In witness whereof, I, the said St. George Lane Fox, have hereunto set my hand
and seal, this Eighth day of April, One thousand eight hundred and seventy-
nine
ST. G. LANE FOX. (L.S.)

page_text: #t
En the Matter of Letters Patent granted to St. George Lane Fox, of
Telegraph Street, in the City of London, for the Invention of
IMPROVEMENTS IN OBTAINING LIGHT BY ELECTRICITY, AND IN CON-
VEYING, DISTRIBUTING, MEASURING AND REGULATING, THE ELECTRIC
CURRENT FOR THE SAME, AND IN THE MEANS OR APPARATUS EMPLOYED
THEREIN," dated the 9th day of October 1878, No. 3988.
DISCLAIMER AND MEMORANDUM OF ALTERATION entered by the
Anglo American Brush Electric Light Corporation, Limited, of Belvedere
Road, Lambeth, in the County of Surrey, the Assignees of the said Letters
Patent, pursuant to the Statutes in that case made and provided.
WHEREAS Letters Patent bearing date the 9th day of October 1878, and
numbered 3988, for the Invention of " IMPROVEMENTS IN OBTAINING LIGHT BY
ELECTRICITY, AND IN CONVEYING, DISTRIBUTING, MEASURING, AND REGULATING
THE ELECTRIC CURRENT FOR THE SAME, AND IN THE MEANS OR APPARATUS
EMPLOYED THEREIN," were granted to St. George Lane Fox, his executors,
administrators, and assigns, for the term of 14 years next ensuing, and to which
Letters Patent a Specification was duly filed on the 9th of April 1879: And whereas
by an indenture bearing date the 29th day of July 1881, and duly entered at the
Great Seal Patent Office, the said St. George Lane Fox assinged to the Anglo
American Brush Electric Light Corporation, Limited, the aforesaid Letters Patent:
And whereas, since the date of the said Letters Patent and of the filing of the
Specification thereto, it has been discovered that certain parts of the said Invention
are of doubtful novelty, and certain other parts are not of that utility which at the

page_text: *
#5
14
"
"
#f
" TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ST. GEORGE
LANE Fox, of Telegraph Street, in the City of London, send greeting.
"WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters Patent,
bearing date the Ninth day of October, in the year of our Lord One thousand
eight hundred and seventy eight, in the forty second year of Her reign, did, for
Herself, Her heirs and successors, give and grant unto me, the said St. George
Lane Fox, Her special license, that I, the said St. George Lane Fox, my
" executors, administrators, and assigns, or such others as I, the said St. George
Lane Fox, 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 Kingdon of Great Britain and Ireland, the Channel Islands,
"and Isle of Man, an Invention for "IMPROVEMENTS IN OBTAINING LIGHT BY
ELECTRICITY, AND IN DISTRIBUTING AND REGULATING THE ELECTRIC CURRENT
FOR THE SAME, AND IN THE MEANS OR APPARATUS EMPLOYED THEREIN," upon
"the condition (amongst others) that I, the said St. George Lane Fox, 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 St. George Lane Fox, 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
thereof, reference being had to the accompanying Drawings, that is to say :-
"
"
**
"My Invention consists of improvements in obtaining light by electricity, and

page_text: "
“in distributing and regulating the electric current for the same, and in the
means or apparatus employed therein.
"In order to produce a light I pass the electric current through a thin strip of
"wire of some suitable material, for which purpose I prefer to use an alloy or
platinum and iridium. The electric lamp in which the light is produced therefore
"consists of two conductors insulated from one another, having this strip or wire
"between them and in contact with each.
"
14
"The material or alloy employed should be capable of standing as high a
degree of temperature as possible without fusing, volatilizing, or falling to pieces;
"it should also have a high specific resistance. The higher the temperature to
"which the material can be raised the more economical will be the light produced,
that is, the light will be greater in proportion to the force or energy expended,
"inasmuch as the radiant energy proceeding from the surface of the material will
"be more and more luminous as the temperature increases. In order to prevent
the deterioration of the material when incandescent I sometimes surround it
"with an atmosphere of nitrogen gas. The quantity of light will be proportional
"to the extent of the luminous surface. The resistance of the luminous material
"and its extent of surface should therefore depend on the amount of light it is
required to give and the electro motive force used; speaking broadly it may be
"said that the resistance of the luminous conductor should be so adjusted or fixed
"that the electro motive force of the mains to which it is attached is just sufficient
"to develop within it the strength of current necessary to raise it to the right
degree of incandescence.
"
In order that the electric force may be conveyed at a high tension, that is,
having high electro-motive force, so that there may not be very great loss from
"the resistance of the (conducting mains or conductors, I make the lamps_when
I use an alloy of platinum and iridium of lengths of fine wires, so that I may
"get a high resistance without having a large extent of luminous surface. I
generally suspend the wire, as shewn in Figures 1 and 2 of the annexed Drawings,
as I find that at a high state of incandescence the alloy becomes soft and would
"not retain its shape if coiled or otherwise twisted.
CE
tr
"
"
"In Figure 1 a represents the wire of alloy of platinum and iridium; it is
suspended between the two conductors b, b, which pass through the top c of the
lamp; d is a cover of glass or other suitable material cemented or hermetically
sealed to the top c. In Figure 2 the wire a is shewn as passing several times
over a bar or tube e of glass or other insulating material, the ends of the wire
being attached as before to the two conductors b, b.
"The way in which I distribute the electric energy so as to work a number of
these lamps from a single source of electricity is represented in the diagram,
Figures 3 and 5, and is as follows:-From one pole or electrode of the electric
generator or generators (situated at A, Figure 3.) proceed one or more large
conductors from which branch out at various points where lights are desired
smaller conductors, which again may have conductors branching off from them,
and so on.
The other pole or electrode of each electric generator is connected
with the earth, so that the conductor and its branches and sub-branches will be
perpetually in a state of electric tension tending to develop currents in every
direction to the earth.
*
One pole of the electric lamp is connected with the earth e, and .this may be
conveniently effected by means of gas or water pipes, where such exist, so that
wherever the circuit is complete between the lamp and any one of these branches
a current of electricity will pass through the thin strip or wire rendering it
incandescent and so produce light.
**
The electro motive force of the electric conducting mains should be kept as
nearly as possible constant at, say, 100 volts or British Association units of
electro motive force.
"A number of secondary batteries, such as Plantés (lead and sulphuric acid), or

page_text: 15
"f
"those formed with plates of copper in a solution of bicarbonate of soda, such
" batteries being joined together in series between the main and the earth will
serve as a kind of reservoir for the electricity. The cells should have a very
large conducting surface, and there should be several batteries connected up at
" various points of the mains, so that by increasing the electro motive force during
"the hours when not much electricity is being used they will become charged and
"the electric force will be stored up in them, so that a sufficient supply will be
"available when the electro motive force falls owing to the draft from the mains
"when the force is most used and needed. The number of cells in each of these
"batteries will depend on the electro motive force of the mains.
**
<<
**
"
"
Figure 5 is a diagram representing a secondary battery joined up between the
"main and the earth for the purpose above described; E indicates earth, and lamps.
In order to keep the electro motive force in the electric mains constant, it is
"desirable to have in the first place several generating machines; also a number of
"reservoir batteries, as before explained; next it is necessary to have some
regulator, such as that about to be described. In my regulator I make use of
"what is known as the quadrant electrometer; in this instrument the position of
"the suspended needle will depend on the relative electro motive force of the so
"called quadrants. By connecting this instrument with the main and the earth
" in the ordinary way the electro motive force of the main will determine the
position of the suspended needle. If it increase or decrease the position of the
"needle will be altered accordingly. Now I fit this electro meter with small pegs
so that a slight deviation of the needle one way or the other will bring it in
" contact with one of these pegs, and thus complete a circuit and set up the electric
" current, which acting upon an electro magnet sets a lever or other suitable
"device in action. The contact with each peg forms a separate circuit acting
independently on two of these lovers or other devices, which are in connection
with steam valves, one diminishing the other increasing the supply of steam to
the engine which works the electric generators. The electro motive force can be
regulated either in this manner or by otherwise effecting the action of the
electric generators through the instrumentality of the currents set up by the
pegs above described, so as to increase or diminish the action of the generators.
Figure 6 represents a quadrant electrometer adapted to regulating the electro
"motive force in the mains, as just described; a, a, are the quadrants, and b the
suspended needle; c, c, are pegs of platinum or other suitable material; and d, d,
are springs situated between the needle band these pegs; e is the wire connecting
"with the main, and f, that connecting with the earth; g, g, represent electro-
magnets in connection with the respective pegs c, c, the said magnets acting on
"levers or other devices for operating the steam valves, as above described.
"
"
$$
"
##
"
$4
"
"
"
"
"1
"
"And having now described the nature of my said Invention, and in what
manner the same is to be performed, I declare that I do not claim generally the
obtaining of light by the incandescence of a continuous conductor nor the lamps
represented in Figures 1 and 2, and hereinbefore described, but I claim as my
improvements in obtaining light by electricity and in distributing and regulating
"the electric current for the same, and in the means or apparatus employed
"therein,-
"
"First. The mode or system hereinbefore described of distributing the electric
"current by mains, branches and sub branches, with returns by earth.'
"Second. In combination with the said mode or system of distributing the
" electric current by mains, branches, and sub-branches, with returns by 'earth,'
"I claim the production of light by the incandescence of a continuous conductor,
as hereinbefore described.
68
"
"Third. The employment as described of secondary batteries as reservoirs of
electricity, in combination with a mode or system of distribution, such as is
" herein before explained.
"Fourth. Constructing apparatus substantially as hereinbefore described and

page_text: represented in Figure 6, for regulating the electro motive force in the mains, by
which the electricity is conveyed.
#
"In witness whereof, I, the said St. George Lane Fox, have hereunto set
iny hand and seal, this Eighth day of April One thousand eight hundred
" and seventy nine.
" ST. GEORGE LANE FOX. (L.S.)"
In witness whereof the said Anglo American Brush Electric Light
Corporation, Limited, have caused their common seal to be hereunto
affixed the Twenty first day of December One thousand eight hundred and
eighty one.
I hereby grant my fiat, giving leave to the above named Anglo American Brush
Electric Light Corporation, Limited (the Assignees and now legal and equitable
owners of the herein before recited Letters Patent) to file in the Great Seal Patent
Office, with the Specification to which the same relates, the above written
Disclaimer and Memorandum of Alteration.
Dated this Twenty fourth day of January One thousand eight hundred and
5 eighty two

page_text: DISCLAIMER AND MEMORANDUM OF ALTERATION entered by the
said St George Lane Fox and The Anglo American Brush Electric Light
Corporation Limited of Belvedere Road Lambeth in the County of Surrey,
pursuant to the Statutes in that case made and provided.
"
WHEREAS Letters Patent bearing date the 9th day of October One thousand
eight hundred and seventy eight and numbered 3988 for the invention of
"IMPROVEMENTS IN OBTAINING LIGHT BY ELECTRICITY AND IN CONVEYING
DISTRIBUTING MEASURING AND REGULATING THE ELECTRIC CURRENT FOR THE
SAME AND IN THE MEANS OR APPARATUS EMPLOYED THEREIN were granted to
St George Lane Fox his executors administrators and assigns for the term of
fourteen years next ensuing and to which Letters Patent a Specification was duly
filed on the ninth day of April One thousand eight hundred and seventy nine And
whereas by an Indenture bearing date the twenty ninth day of July One thousand
eight hundred and eighty one and duly entered at the Great Seal Patent Office
the said St George Lane Fox assigned to the Anglo American Brush Electric Light
Corporation Limited the aforesaid Letters Patent And whereas on the twenty
sixth day of January One thousand eight hundred and eighty two the said

page_text: Corporation as assignees of the said Letters Patent did by leave of Her Majesty's
Solicitor General as certified by his fint and signature and for reasons then shown
file in the Great Seal Patent Office a Disclaimer and Memorandum of Alteration
disclaiming the words "conveying" and "measuring" from the title of the said
Letters Patent and disclaiming certain parts of the specification thereto and
making certain alterations therein And whereas by an Agreement bearing date
the twelfth day of August One thousand eight hundred and eighty two and duly
entered at the Great Seal Patent Office and made between the said Anglo
American Brush Electric Light Corporation Limited of the one part and the said
St George Lane Fox of the other part for the consideration therein mentioned the
said Anglo American Brush Electric Light Corporation Limited agreed to resell
to the said St George Lane Fox and the said St George Lane Fox agreed to
repurchase the said Letters Patent as from the date of the said agreement
And whereas since the filing of the said Disclaimer and Memorandum of Alteration
the said St George Lane Fox has been advised that certain parts of the said
invention in addition to those already disclaimed by the said Corporation by
the said Disclaimer and Memorandum of Alteration are of doubtful utility and
that certain of the claims in the Specification of the said Letters Patent are of
doubtful validity and the said St George Lane Fox is for the above reasons
desirous of entering a Disclaimer and Memorandum of Alteration in respect of
the said Letters Patent and of thereby disclaiming and altering certain portions of
the Title thereof and of the Specification filed thereto as amended by the Disclaimer
and Memorandum of Alteration aforesaid and the said Anglo American Brush
Electric Light Corporation Limited consent to be parties to such Disclaimer and
Memorandum of Alteration NOW KNOW ALL MEN that the said St George
Lane Fox and the said Anglo American Brush Electric Light Corporation Limited
therefore disclaim from the Title of the Letters Patent the words "in obtaining
light by electricity and" and they further alter the title by striking out therefrom
the words "the same and substituting for these words the words "obtaining
light by electricity;" and they disclaim from the said specification reference being
had to the Queen's Printers printed copy of the said former Disclaimer and
Memorandum of Alteration the words "in obtaining light by electricity and" in
in line forty
page two lines forty two and forty three and the words "the same
four and they substitute for these two words the words 'obtaining light by
electricity" and they disclaim the words in obtaining light by electricity and
in line fifty five on the same page, and the words "the same in page three line
one and they substitute for these two words the words "obtaining light by
electricity" and they disclaim from the said specification the following parts viz :-
the word "or" in page three line fifty six; the words "those formed with plates
of copper in a solution of bicarbonate of soda" in page four line one; all the
"
next in line fifteen and the word
portion in page four between the word
"described "in line thirty nine both inclusive; the words "in obtaining light by
in line forty four and the words the same
electricity; and
in line forty five
and they substitute for these two words the words "obtaining light by electricity;"
and they disclaim all the portion in page four between the word "first" in line
forty seven and the word Third" in line fifty three both inclusive; and all the
portion in line fifty six page four and in lines one and two page five and they
also strike out and disclaim Figure 6 on the sheet of drawings attached to the
said specification.
"
"
"
"
"
And the said specification when so amended by Disclaimer and Memorandum
of Alteration will read and be as follows:-

page_text: "
"the ninth day of October in the year of Our Lord One thousand eight hundred
"and seventy eight in the forty second year of Her reign, did for herself, her
" heirs and successors give and grant unto me the said St George Lane Fox
"Her special license that I the said St George Lane Fox my executors adminis-
"trators and assigns or such others as I the said St George Lane Fox 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 IMPROVEMENTS IN DISTRIBUTING AND REGULATING THE
"ELECTRIC CURRENT FOR OBTAINING LIGHT BY ELECTRICITY AND IN THE MEANS
OR APPARATUS EMPLOYED THEREIN' upon the condition (amongst others) that
I the said St George Lane Fox 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
inanner 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 St George
"Lane Fox 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 thereof, reference being had to the
accompanying drawings, that is to say :-
"
"
es
"
"
"
"
<<
My invention consists of improvements in distributing and regulating the
" electric current for obtaining light by electricity and in the means or apparatus
employed therein.
«
"
"In order to produce a light I pass the electric current through a thin strip of
"wire of some suitable material for which purpose I prefer to use an alloy of
platinum and iridium. The electric lamp in which the light is produced
"therefore consists of two conductors insulated from one another having this strip
or wire between them and in contact with each.
"
"
"
"The material or alloy employed should be capable of standing as high a degree
" of temperature as possible without fusing, volatilizing or falling to pieces; it
"should also have a high specific resistance. The higher the temperature to which
the material can be raised the more economical will be the light produced, that
is, the light will be greater in proportion to the force or energy expended,
inasmuch as the radiant energy proceeding from the surface of the material will
"be more and more luminous, as the temperature increases.
In order to prevent
"the deterioration of the material when incandescent I sometimes surround it with
an atmosphere of nitrogen gas. The quantity of light will be proportional to the
"extent of the luminous surface. The resistance of the luminous material and its
" extent of surface should therefore depend on the amount of light it is required to
give and the electro motive force used; speaking broadly it may be said that the
" resistance of the luminous conductor should be so adjusted or fixed that the
" electro motive force of the mains to which it is attached is just sufficient to
develop within it the strength of current necessary to raise it to the right degree
of incandescence.
"
st
"
"
"
"In order that the electric force may be conveyed at a high tension, that is,
having high electro motive force, so that there may not be very great loss from the
"resistance of the conducting mains or conductors, I make the lamps when I use
an alloy of platinum and iridium of lengths of fine wires, so that I may get a
high resistance without having a large extent of luminous surface. I generally
suspend the wire, as shown in Figures 1 and 2 of the annexed drawings, as I
"find that at a high state of incandescence tho alloy becomes soft and would not
"retain its shape if coiled or otherwise twisted.
#
<<

page_text: #
"In Figure 1 a represents the wire of alloy of platinum and iridium; it is
suspended between the two conductors b b which pass through the top c of the
lamp; d is a cover of glass or other suitable material cemented or hermetically
"sealed to the top c. In Figure 2 the wire a is shown as passing several times
"over a bar or tube e of glass or other insulating material, the ends of the wire.
"being attached as before to the two conductors b b.
**
"The way in which I distribute the electric energy so as to work a number of
"these lamps from a single source of electricity is represented in the diagram
Figures 3 and 5 and is as follows:-From one pole or electrode of the electric
generator or generators (situated at A Figure 3) proceed one or more large
" conductors from which branch out at various points where lights are desired
"smaller conductors, which again may have conductors branching off from them
"and so on.
The other pole or electrode of each electric generator is connected
"with the earth so that the conductor and its branches and sub-branches will be
"perpetually in a state of electric tension tending to develop currents in every
"direction to the earth.
"
"One pole of the electric lamp is connected with the earth e and this may be
conveniently effected by means of gas or water pipes where such exist, so that
"wherever the circuit is complete between the lamp and any one of these branches
a current of electricity will pass through the thin strip or wire rendering it
" incandescent and so produce light.
"The electro motive force of the electric conducting mains should be kept as
nearly as possible constant at, say, 100 volts or British Association units of
" electro motive force.
"
"A number of secondary batteries such as Plantés (lead and sulphuric acid) such
"batteries being joined together in series between the main and the earth will
serve as a kind of reservoir for the electricity. The cells should have a very
large conducting surface and there should be several batteries connected up at
" various points of the mains so that by increasing the electro motive force during
"the hours when not much electricity is being used they will become charged and
"the electric force will be stored up in them so that a sufficient supply will be
"available when the electro motive force falls owing to the draft from the mains
"when the force is most used and needed. The number of cells in each of these
" batteries will depend on the electro motive force of the mains.
Figure 5 is a diagram representing a secondary battery joined up between the
"main and the earth for the purpose above described; E indicates earth and
7 lamps.
"In order to keep the electro motive force in the electric mains constant, it is
"desirable to have in the first place several generating machines; also a number of
" reservoir batteries as before explained.
"
**
at
"And having now described the nature of my said invention and in what
manner the same is to be performed I declare that I do not claim generally the
obtaining of light by the incandescence of a continuous conductor nor the lamps
represented in Figures 1 and and hereinbefore described, but I claim as my
improvements in distributing and regulating the electric current for obtaining
light by electricity and in the means or apparatus employed therein :-
"The employinent as described of secondary batteries as reservoirs of electricity,
" in combination with a mode or system of distribution such as is hereinbefore
explained.
"In witness whereof I the said St George Lane Fox have hereunto set my
"hand and seal this eighth day of April One thousand eight hundred and
“ST G. LANE FOX (L.S.)"

page_text: In witness whereof the said St George Lane Fox has hereunto set his hand and
seal and the said Anglo American Brush Electric Light Corporation Limited
have caused their common seal to be hereunto affixed the twenty ninth
day of November One thousand eight hundred and eighty two
he Common Seal of the Anglo American Brush
Electric Light Corporation, Limited, affixed
in the presence of the undersigned, being
two of the Directors and the Secretary of
the said Corporation.
Company's
Seal.
Notice of the application for leave to file the above written Disclaimer and
Memorandum of Alteration having been advertized in accordance with my
directions, and the Oppositions entered against the said Disclaimer being placed
upon the File, having been disposed of by me
I hereby grant my Fiat giving leave to the above named St. George Lane Fox
and the Anglo American Brush Electric Light Corporation Limited to file in the
Office of the Commissioners of Patents with the Specification to which the same
relates the above written Disclaimer and Memorandum of Alteration; but never-
theless upon condition that no proceedings for infringement be taken against the
Swan United Electric Light Company Limited or against Messieurs R. E. B.
Crompton and Cuy or against any person or persons in respect of the use or
employment of any combination of instruments or apparatus constituting the
system described and claimed in the hereinbefore written Specification, which
has been set up on or before the eighth day of December 1882. Or in respect of
any combination of instruments or apparatus constituting the system described and
claimed as aforesaid which has been or shall be set up after the said eighth day of
December 1882 under any contract or contracts bonâ fide entered into by the said
Swan United Electric Light Company Limited or Mess". R. E. B. Crompton and
Company on or previous to the said eighth day of December 1882.
Particulars of all such apparatus or systems as have been set up on or previous
to the said eighth day of December 1882 and of all contracts bona fide entered
into on or previous to that date to be furnished to The Solicitor General, to the
said St. George Lane Fox, and to the Anglo American Brush Electric Light
Corporation Limited and the same to be verified by Statutory Declaration on or
before the 21 day of August 1883 and an opportunity to be given to the said
S' George Lane Fox and the Anglo American Brush Electric Light Corporation
Limited to inspect the same.
Any question of bona fides to be referred to the Solicitor General who shall be
nt liberty if he think fit to appoint any person or persons to enquire into and
report upon the question or questions in dispute.
The costs of and incidental to such enquiry to be borne by the parties in such
manner as to the Solicitor General shall seem equitable.
Dated this twenty fifth day of July 1883

page_text: We, the above mentioned St. George Lane Fox and the Anglo American Brush
Electric Light Corporation Limited hereby accept and undertake to abide by
the conditions imposed by the Solicitor General and mentioned in the above
written Fiat. Dated this 25th day of July 1883.