IMPROVEMENTS IN AND CONNECTED WITH ELECTRIC LAMPS,
Year: 1882

page_text: LETTERS PATENT to Shackleton Hallett, Director of "The Electrolytic
Company," Charlotte Street, Blackfriars in the County of Surrey and of
No 1, Hare Court Temple in the City of London, Esquire, Barrister-at-Law for
an invention of "IMPROVEMENTS IN AND CONNECTED WITH ELECTRIC LAMPS,
PROVISIONAL SPECIFICATION left by the said Shackleton Hallett at the
Office of the Commissioners of Patents on the 31st May 1882.
SHACKLETON HALLETT, Director of the Electrolytic Company, Charlotte Street,
Blackfriars in the County of Surrey and of No 1 Hare Court Temple, in the City of
London Esquire, Barrister at Law, "IMPROVEMENTS IN AND CONNECTED WITH
ELECTRIC LAMPS, AND IN ELECTRODES THEREFOR
"
This Invention relates to certain improvements upon the subject matter of
Letters Patent bearing date 17th September 1881 No 4017, and granted to me and
to electrodes for electric lamps generally and primarily to that class of electric
lamps in which light is produced by the incandescence, on the passing of an electric
current, of a conductor or bridge of carbon enclosed in a glass vessel from which the
air has been exhausted and my invention consists chiefly of improvements in the
carbon conductor itself and in the mode of attaching it to its connections and also
to the preparation of carbons for electric lamps whether the arc or incandescent
description and an improvement in the sockets of electric lamps and in the method
of attaching the lamp socket to the bracket or holder, and an improvement in the
contact breaker of electric lamps.
In the manufacture of carbons for electric lamps, there has hitherto existed
considerable difficulty in securing a substance possessing sufficient homogeneity of
texture and presenting a uniform resistance to the electric current, one of the
objects of this invention is to overcome this difficulty by the treatment of certain
substances and their application to secure the requisite uniformity of quality or
texture in every part of the carbon.
To obtain this result (for electric lamps of the incandescent type) I take a cocoa-

page_text: nut, and having stripped off the outer husk, I make the outside surface of the shell
smooth either by working it in a lathe with emery cloth or applying a sand blast,
or by filing or grinding by an emery wheel or as may be convenient.
The nut is then either cut into larger or smaller segments quarter or half
segments, or otherwise according to the size and shape of the electrode required.
The fruit or pulp is then removed and the inside of the shell scraped clean, the
shell is then divided into slices or strips of the size and partly of the shape required
for the electrode by means of a fine band saw with very little "set" or by other
suitable means-The electrodes may be shaped-out in flat long pieces with
projecting ends or projections at the ends for convenience of connection with the
platinum conductors or holders.
The pieces of nut shell so cut out are then laid flat on a piece or block of wood
serving as a work block to which they are affixed by glue. They are then reduced
to the required thickness and smoothness by filing or by grinding or by the use of
a fine chisel, or by a combination of these methods. When one side is thus finished
the proposed electrode is then detached from the wood by water or steam and
again affixed by glue to the work block so as to expose the unfinished side; this
side is then ground or filed and finished as before described.
The pieces of cocoa-nut shell are then dried in a water bath (that is to say an
oven surrounded by a steam jacket and heated by means of the steam passing
through such steam jacket) or by other well known means to remove any moisture
either natural or which they may have absorbed in the above treatment-When
effectually dried the pieces can be bent to the required shape by first submerging
them for a short time in heated cocoa-nut oil, at à temperature of 200° Fahrenheit
or more is found desirable, (other oils than that of the cocoa-nut may be used but
I prefer cocoa-nut oil) and then bending them in the oil, and when bent to the
required shape the pieces are placed in the carbonizing metallic mould hereinafter
described.
In further application of this treatment to prepare carbon electrodes both for
arc or incandescent lamps I take preferably carbon produced from the shell of the
cocoa-nut as hereinafter described, or the carbon from distillation of petroleum or
other carbon in a state of powder or minute division as to its particles; to this I
add sufficient water and sufficient fine gelatine, size, or glue to bring the mixture to
a mass of the consistancy of cream, I then heat the same and bring it to about
150° Fahrenheit I then add sufficient tannic acid to the heated mixture to coagulate
the carbon mass. The resultant paste is then again heated to reduce it to the
consistancy of about bread dough it is then pressed and moulded.
In place of pulverized carbon any ligneous or vegetable pulp (which has been
purified or not by treatment with any of the mineral acids in a diluted form) may
be substituted, tannic acid and gelatine being mixed with such pulp in the manner
already prescribed and the pulp is semi-dried and pressed and moulded.
To carbonize the prepared cocoa-nut-slips the moulded carbon mass, or ligneous,
or vegetable pulp, I proceed as follows:-The cocoa nut slips bent in manner before
described, or the moulded carbon mass, or ligneous or vegetable mass are either
placed or retained in a carbonizing metallic mould constructed substantially as
follows: In a plate of nickel steel, or other suitable metal, grooves are cut right
through corresponding to the shape of the proposed carbon electrodes, this sheet is
planed true on both sides and fitted to two corresponding sheets planed true, one
at the top and the other at the bottom and the whole are then bolted together by
bolts at convenient distances and arranged in such a way that the mould may be
easily separated from its coverings. The mould when charged with slips of prepared
cocoa-nut shell, compressed carbon mass, or ligneous or vegetable pulp prepared
respectively as before described is bolted together so as to make the mould
practically air tight, the mould is then submitted or heated gradually to nearly a
white heat in a carbonizing furnace until the contents of the mould have become
perfectly carbonized. The mould when sufficiently cool is opened and the carbonized
bridges or rods are removed, or the cocoa-nut bridges, moulded carbon mass, or

page_text: ligneous or vegetable mass may be carbonized in the manner now usually adopted
for carbonizing electrodes for electric lamps.
When cool the pieces of cocoa-nut shell carbon, compressed carbon, or carbonized
ligneous or vegetable mass, are removed from the mould or from the carbonizing
chamber and are forth with (if for incandescent lamps) tested with a testing
current of electricity in order to ascertain whether they offer uniform resistance to
the electric current. Those pieces which are not of uniform resistance are sub-
merged in some hydro-carbon oil (cocoa-nut oil by preference) previously heated
for some time to about a boiling point and when submerged a current of electricity
of sufficient strength to bring the proposed electrode to a bright red heat is
passed through them until by receiving a sufficient deposit of carbon from the
oil their resistance is brought up to the desired uniformity.
The above process may be carried out after the electrodes are mounted as
hereinafter described.
As to the making of the incandescent lamps a glass globe is employed, having.
an aperture at the base and a small hollow stem piece projecting from any
convenient part of it for the purpose of exhausting the air at the appropriate
time. The base of the globe is open for the insertion of the mounted carbon
electrode prior to the operation of exhausting the air.
The carbon electrode is mounted as follows:-A glass socket corresponding with
the opening at the base of the globe and to which it has eventually to be fused, has
two pieces of platinum wire fused into it projecting through the glass both on the
inside and the outside, on the outside they may be left straight for the purpose of
connecting up at and through the concave or square sockets or plugs hereinafter.
described.
To the two pieces of platinum projecting internally are fastened either by hard
soldering or other suitable means, two small flat pieces of mi the distance
apart of which said metal pieces will correspond with the dista between the
thickened ends of the carbon electrode.
On to the two metallic plates the ends of the carbon electrode are fastened either
by hard soldering, by small metallic clips or by the following means, viz.—
I take small pieces of the carbonized cocoa nut or any form of carbon and
pulverize the same until the particles are in a state of minute division. To this I
add sufficient water and sufficient fine gelatine, size, or glue to bring the mixture
to about the consistancy of cream I then heat the same bringing it to about
150° Fahrenheit. I then add sufficient tannic acid to the heated mixture to
coagulate the carbon mass, the resultant paste is then laid around the point of
junction of the electrode and the conductors. The mounted electrodes are then
dried in a water bath or other well known means. The junction of the electrode
supports is then slightly heated by a blow-pipe flame.
The glass socket with the carbon electrode mounted upon it is now to be fused
into the aperture at the bottom of the glass globe from which the air is exhausted
in the usual way.
The base or socket of the globe may then be placed in a brass socket or plug of
conical or square shape moulded internally hollow and shaped to the base of the
globe at the upper and largest end of the said plug.
To the interior or the metallic substance of the conical piece or plug itself is
soldered one of the conducting wires of the lamp or I may clamp the same on to
the metallic interior of the plug by means of a screw passing through the solid side
of the plug, or I have a slot in the solid part of the interior of the conical plug in
which the conducting wire rests and forms contact, or it may be clamped gripped
or screwed or held in any convenient way to the metallic substance of the plug.
To the other conducting wire of the lamp I first solder a thickish piece of copper
wire and then cover the same with some insulating material the unsoldered end of
the copper wire protrudes about a quarter of an inch from the base of the square
or conical plug and this end I platinize either in a bath by the electrolytic process
or I solder a small pieces of platinum on to the end of it.

page_text: The square or conical plug may or may not at its upper end where the neck or
base of the globe of the lamp rests upon it be filled with a sufficient quantity of
suitable cement.
The bracket or holder to be used has a square or circular cavity turned in its
surface corresponding to the outer surface of the conical or square plug.
At the bottom of this socket of the bracket or holder into which the conical plug
holding the electric lamp is to be fitted, I have a connector formed of two small
spring contact pieces which may be of hard spring copper platinized these are
soldered on to an insulated copper wire which passes through the hollow tube of
the bracket or holder into this socket the plug carrying the globe is dropped and
simultaneously the platinized end of the wire is clipped between the spring contact
pieces perfect contact being obtained, by this arrangement an electric lamp is
obtained of strong construction and having the more delicate and easily injured
portion of its construction effectually protected from the effects of rough or careless
handling.
Where gas fittings already exist I utilize the same by bringing one wire properly
insulated through the hollow of the bracket tube and connecting the same as above
mentioned with a spring clip contained in a metallic socket on to the gas fitting
and I use the metallic bracket itself and the accompanying pipes in place of a
second wire for the return current, contact being made by the metallic plug of the
lamp, or I use the bracket alone for the return current and at the back thereof
where it is affixed to the wall or ground or at a short distance from the point
where the bracket is affixed to the wall I solder or otherwise connect a second
wire.
The square or conical plug may be steadied in the holder where additional
steadiness is required other than that afforded by its shape by passing a screw or
pin through the holder and the plug or using any suitable clip or catch.
To make and break contact I use the following novel form of contact breaker.
In gas brackets I take out the plug of the ordinary tap (or in brackets or holders
specially constructed I use a tap similar to that used in gas brackets and treated
as follows) in the bracket there is to be found a transverse hole of the size of the
bore of the pipe or less as the case may be as already mentioned through the
tubular portion of the bracket or holder a properly insulated copper wire is passed
having at one end a clip piece into which the wire of the lamp falls or is clipped.
At the point where is the gas tap or plug this wire is severed and on to the top side
of the end of one of these wires at the tap opening I solder a flat platinum contact
piece and on to the reverse side of the other half of the wire I solder another
platinum flat contact piece. Through the hole in the plug of the tap I place a
copper wire thoroughly insulated by or with a hard resisting material such as
Ebonite vulcanized fibre or the like and projecting sufficiently to have soldered to
each end of it a flat platinum contact piece, I then insert the plug in the pipe
(filing away if necessary portions of the tube for that purpose) and arrange the
plug in such a way with a small stop pin as to admit of its being turned partly in
one particular direction to a certain point on and off when on the four platinum
contact pieces are all in connection-when off the tap is turned in the opposite
direction and the contact is broken so acting as a switch.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Shackleton Hallett in the Great Seal Patent Office on the
30th November 1882.
"
SHACKLETON HALLETT Director of The Electrolytic Company" Charlotte
Street Blackfriars in the County of Surrey and of 1 Hare Court Temple in the
City of London Esquire Barrister at Law "IMPROVEMENTS IN AND CONNECTED
WITH ELECTRIC LAMPS AND IN ELECTRODES THEREFOR
"
This Invention relates to certain improvements upon the subject matter of
Letters Patent bearing date 17th September 1881 No 4017 and granted to me and
to electrodes for electric lamps generally and primarily to that class of electric lamps
in which light is produced by the incandescence of the passing of an electric
current of a conductor or bridge of carbon enclosed in a glass vessel from which
the air has been exhausted; and my invention consists chiefly of improvements in
the carbon conductor itself and in the mode of attaching it to its connections and
also to the preparation of carbons for electric lamps whether of the arc or incan-
descent description and an improvement in the sockets of electric lamps and in the
method of attaching the lamp and socket to the bracket or holder and an
improvement in the contact breaker of electric lamps.
In the manufacture of carbons for electric lamps there has hitherto existed con-
siderable difficulty in securing a substance possessing sufficient homogeneity of
texture and presenting a uniform resistance to the electric current one of the
objects of this invention is to overcome this difficulty by the treatment of certain
substances and their application to secure the request uniformity of quality or
texture in every part of the carbon
To obtain this result (for electric lamps of the incandescent type) I take a
cocoanut and having stripped off the outer busk I make the outside surface of the
shell smooth either by working it in a lathe with emery cloth or applying a sand
blast or by filing or grinding by an emery wheel as may be convenient The nut
is then either cut into larger or smaller segments quarter or half segments or
otherwise according to the size and shape of the electrode required. The fruit or
pulp is then removed and the inside of the shell scraped clean. The shell is then
divided into slices or strips (of the size and partly of the shape required for the
electrode) by means of a fine band saw with very little set or by other suitable
means, the electrode may be shaped out in flat long pieces with projecting ends or
projections at the ends for convenience of connection with the platinum conductors
or holders.
The pieces of nut shell so cut out are then laid flat on a piece or block of wood
serving as a work block to which they are affixed by glue. They are then reduced
to the required thickness and smoothness by filing or by grinding or by use of a
fine chisel or by a combination of these methods. When one side is thus finished
the proposed electrode is then detached from the wood by water or steam and
again affixed by glue to the workblock so as to expose the unfinished side, this
side is then ground or filed and finished as before described.
The pieces of cocoanut shell are then dried in a water bath (that is to say an
oven surrounded by a steam jacket and heated by means of the steam passing
through such steam jacket) or by other well known means to remove any moisture
either natural or which they may have absorbed in the above treatment. When
effectually dried the pieces can be bent to the required shape by first submerging
them for a short time in heated cocoa nut oil at a temperature of 200° Fahrenheit
or more if found desirable (other oils than that of the cocoa-nut may be used-.
cocoa nut oil gives good result) and then bending them in the oil and when bent

page_text: to the required shape the pieces are placed in a carbonizing metallic mould herein-
after described.
In further application of this treatment to prepare carbon electrodes both for
arc or incandescent lamps I take carbon in a state of powder or minute division as
to its particles; preferably carbon produced from the shell of the cocoa-nut as
hereinafter described or the carbon from distilation of crude petroleum to this I add
sufficient water and sufficient fine gelatine size or glue to bring the mixture to a
mass of consistency of cream I then heat the same and bring it to about 150°
Fahrenheit I then add sufficient taunic acid to the heated mixture to coagulate
the carbon mass the resultant paste is then again heated to reduce it to the
consistency of about bread dough it is then pressed and moulded and dried.
In place of pulverized carbon any ligneous or vegetable pulp which has been
purified by treatment with any of the mineral acids in a diluted form may be
substituted for making electrodes, tannic acid and gelatine being mixed with such
pulp in the manner already prescribed and as before described and the pulp is
semidried and pressed and moulded.
To carbonize the prepared cocoa-nut shell slips the moulded carbon massor
ligneous or vegetable pulp I proceed as follows. The cocoa nut slips bent in
manner before described or the moulded carbon mass or ligneous or vegetable mass
are either placed or retained in a carbonizing metallic mould constructed as
follows:-
In a plate of nickel steel or other suitable metal grooves are cut right through
corresponding to the shape of the intended carbon electrodes. This sheet is planed
true on both sides and fitted to two corresponding sheets planed true one at the
top and the other at the bottom and the whole is then bolted together by bolts at
convenient distances and arranged in such a way that the mould may be easily
separated from its coverings the mould when charged with slips of prepared cocoa
nut shell compressed carbon mass or ligneous or vegetable pulp prepared respec-
tively as before described is bolted together so as to make the mould practically
air tight the mould is then submitted or heated gradually to nearly a white heat
in a carbonizing furnace until the contents of the mould have become perfectly
carbonized the mould when sufficiently cool is open and the carbonized bridges or
rods are removed. The moulded carbon mass or the cocoanut bridges or ligneous
vegetable mass may be carbonized in the manner now usually adopted for
carbonizing electrodes for electric lamps.
When cool the pieces of cocoa nut shell carbon compressed carbon or carbonized
ligneous or vegetable mass are removed from the mould or from the carbonizing
chamber and are forthwith (if for incandescent lamps) tested with a testing
current of electricity in order to ascertain whether they offer a uniform resistance
to the electric current those pieces which are not of uniform resistance are
submerged in some hydrocarbon oil as cocoanut oil previously heated for some time
to about a boiling point and when submerged a current of electricity of sufficient
strength to bring the proposed electrode to a bright red heat is passed through
them until by receiving a sufficient deposit of carbon from the oil their resistance
is brought up to the desired uniformity
The above process may be carried out after the electrodes are mounted as
hereinafter described. As to the making of the incandescent lamps a glass globe
is employed having an aperture at the base and a small hollow stem piece
projecting from any convenient part of it for the purpose of exhausting the air at
the appropriate time the base of the globe is open for the insertion of the mounted
carbon electrode all as usual.
The carbon electrode is mounted as follows: A glass socket corresponding with
the opening at the base of the globe in which it is intended to be used, has two
pieces of platinum wire fused into it and projecting through the glass both on the
inside and the outside. On the outside they may be left straight for the
purpose of connecting up in and through the cocoa nut square sockets or plugs
hereinafter described.

page_text: To the two pieces of platinum projecting internally are fastened either by hard
soldering or other suitable means two small flat pieces of metal the distance apart
of which said metal pieces will correspond with the distance between the thickened
ends of the carbon electrode.
On to the metallic plates the ends of the carbon electrode are fastened either by
hard soldering by small metallic clips or by the following means viz I take small
pieces of the carbonized cocoanut or any form of carbon and pulverize the same
until the particles are in a state of minute division. To this I add sufficient water
and sufficient fine gelatine size or glue to bring the mixture to about the
consistancy of cream,. I then heat the same and bring it to about 150° F. I then
add sufficient tannic acid to the heated mixture to coagulate the carbon mass the
resultant paste is then laid round the point of junction of the electrode and the
conductors the mounted electrodes are then dried in a water bath or other well
known means.
The junction of the electrode supports is then slightly heated by a
blow pipe flame.
The glass socket with the carbon electrode mounted upon it is now to be fused
into the aperture at the bottom of the glass globe from which the air is to be
exhausted in the usual way.
The base or socket of the globe may now be placed in a brass socket or plug of
conical or square shape moulded internally hollow and shaped to the base of the
globe at the upper and largest end of the plug
To the interior of the metallic substance of the conical piece or plug itself is
soldered one of the conducting wires of the lamp or I may clamp the same on to
the metallic interior of the plug by means of a screw passing through the solid
side of the plug or I have a slot in the solid part of the interior of the conical plug
in which the conducting wire rests and forms contact or it may be clamped or
gripped or screwed or held in any convenient way to the metallic substance of the
plug. To the other conducting wire of the lamp I first solder a thickish piece of
copper wire and then cover the same with some insulating material the unsoldered
end of the copper wire protrudes about a quarter of an inch from the base of the
square or conical plug and this end I platinise either in a bath by the electrolytic
process or I solder a small piece of platinum on to the end of it.
The square or conical plug may or may not at its upper end, where the neck or
base of the globe of the lamp rests upon it, be filled with a sufficient quantity of
suitable cement.
The bracket or holder to be used has a square or circular cavity turned in its
surface corresponding to the outer surface of the conical or square plug.
At the bottom of this socket of the bracket or holder into which the conical
plug holding the electric lamp is to be fitted I have a connector formed of two
small spring contact pieces which may be of hard spring-copper platinised these
are soldered on to an insulated copper wire which passes through the hollow tube
of the bracket or holder and into this socket the plug carrying the globe is placed
and simultaneously the platinised end of the wire is clipped between the spring
contact pieces, perfect contact being obtained the removal is equally simple. By
this arrangement an electric lamp is obtained of strong construction and having
the more delicate and easily injured portions of its construction effectually
protected from the effects of rough or careless handling.
The square or conical plug may be steadied in the holder where additional
steadiness is required other than that afforded by its shape by passing a screw or
pin through the holder and the plug.
To make and break contact I use the following novel form of contact breaker.
In gas brackets I take out the plug of the ordinary tap (and in brackets or holders
specially constructed) I use a tap similar to that used in gas brackets and treated
as follows-In the bracket there is to be found a transverse hole of the size of the
bore of the pipe or less as the case may be as already mentioned through the
tubular portiou of the bracket or holder a properly insulated copper wire is passed
having at one end a clip piece into which the wire of the lamp falls or is clipped.

page_text: At the point where is the gas tap or plug this wire is severed and on to the top
side of the end of one of these wires at the tap opening I solder a flat platinum
contact piece and on to the reverse side of the other half of the wire I solder
another platinum flat contact piece through the hole in the plug of the tap I place
a copper wire thoroughly insulated by or with a hard resisting material such as
ebonite vulcanized fibre or the like and projecting sufficiently to have soldered to
each end of it a flat platinum contact piece I then insert the plug in the pipe
(filing away if necessary portions of the tube for that purpose and arrange the
plug in such a way with a small stop pin as to permit of its being turned only in
one particular direction to a certain point "on" and "off.". When turned " on
the four platinum contact pieces are all in connection; when "off" the tap is
turned in the opposite direction and the contact is broken so acting as a switch.
Having now described the said Invention I claim :-
"
First. The manufacture of electrodes for electric lamps from cocoa nut shell as
and for the purpose herein set forth
Second. The manufacture of carbon electrodes from pulverous carbonaceous
matter prepared with gelatine or glue and the admixture of tannic acid forming
the carbon mass which is to be moulded pressed and recarbonized as herein set
forth,
Thirdly The manufacture of electrodes from ligneous or vegetable pulp treated
with mineral acid in dilute form and mixed with gelatine or glue and tannic acid
to form the carbon mass which is to be moulded pressed and carbonized as herein
set forth.
Fourth. The mounting of the electrodes for incandescent lamps with the sockets
and connections of the bulb and of the supporting bracket and the contact breaker
switch device constructed and operating as and for the purpose herein set forth.
In witness whereof I the said Shackleton Hallett have hereunto set my hand
and seal this twenty eighth day of November in the year of our Lord one
thousand eight hundred and eighty two
In the presence of
WALTER A. BARLOW
Patent Agent & Engineer
6 St Pauls Churchyard
London EC
SHACKLETON HALLETT (L.S.)