IMPROVEMENTS IN AND RELATING TO ELECTRIC LAMPS on LIGHTING APPARATUS, AND IN THE MANUFACTURE OF PORTIONS OF THE SAME."
Year: 1881

page_text: of
"
LETTERS PATENT to William Robert Lake, of the Firm of Haseltine, Lake,
& Co., Patent Agents, Southampton Buildings, London, for an Invention
IMPROVEMENTS IN AND RELATING TO ELECTRIC LAMPS on LIGHTING
APPARATUS, AND IN THE MANUFACTURE OF PORTIONS OF THE SAME." A com-
munication from abroad by Hiram Stevens Maxim, of Brooklyn, New York,
United States of America.
PROVISIONAL SPECIFICATION left by the said William Robert Lake at the
Office of the Commissioners of Patents on the 21st July 1881.
OF
WILLIAM ROBERT LAKE, of the Firm of Haseltine, Lake, & Co., Patent
Agents, Southampton Buildings, London. "IMPROVEMENTS IN AND RELATING TO
ELECTRIC LAMPS OR LIGHTING APPARATUS, AND IN THE MANUFACTURE
PORTIONS OF THE SAME" [A communication from abroad by Hiram Stevens
Maxim, of Brooklyn, New York, United States of America.]
This Invention relates to electric lamps or lighting apparatus of the kind which
are known as incandescent lamps, and to the method of manufacturing the same,
involving improvements in the means of sealing the wines into the globe surrounding
the light giving or incandescent conductor, novel and useful processes for the
treatment and preparation of the carbon and conducting strips or filaments, and
certain accessory devices, hereinafter to be more fully described, for use with the'
said lamps when completed.
The said Invention comprises the following features, that is to say:--
Cutting out straight blanks from a sheet of paper, block of wood, or any suitable
fibrous material, carbonizing them in a closed retort or muffle, and then bending
them into the form of a loop or arch, in which condition they are to be electrically
heated under such conditions that they will ncquire a permanent set without being
injured or consumed; also cutting the conducting strips from previously carbonized
sheets of fibrous or textile material, and bending and then treating them to give
them a permanent set; also carbonizing and electrically heating in a carbonaceous
gas or vapor narrow sheets or strips of the same material, as above named, and
LD011

page_text: •
then cutting therefrom the conducting filaments; also the method of sealing the
wires into the globe by drawing them while hot through suitable perforations in a
glass stopper which is subsequently ground into or otherwise fitted air tight into a
lamp globe; also forming the conductors which pass through the ground glass
stopper or conical steel plugs which are introduced by grinding into a perforation
in a glass stopper closing the globe air-tight; also scaling the conducting wires in
a glass plug or stopper by surrounding them by a number of layers of a metallo-
vitreous cement, each layer containing less metal in its composition than the one
which it encloses, and then moulding the glass around the portions of the wire
thus covered; also an incandescent conductor formed of two or more straight strips
of carbon attached in the usual manner to two metallic wires, and having their
free ends joined by attachment to a mass of conducting material to form a con-
tinuous conductor. And the Invention comprises a bracket or chandelier for use
with the above described lamps, so constructed as to both hold the lamps and
convey the current to and from them.
In carrying the said Invention into practice a number of blanks are formed from
sheets of fibrous material, the general shape being that of a narrow strip with
gradually enlarged butts or ends. These strips being straight occupy but little
space, so that a large number of them may be packed into the muffle at one time
and carbonized. When thoroughly charred the strips are bent and their ends
fixed in clamps which form the terminals of electric circuits, and are adapted to be
covered by a bell glass receiver from which the air is exhausted and a carbon
bearing gas or vapor substituted. The clamps are arranged in pairs and placed so
A current of
as to keep the carbons in the form to which they have been bent.
sufficient power is then directed through each carbon conductor for a desired length
of time, the effect of which is two-fold, first, to lower the resistance of each
conductor to a predetermined standard, and second, to fix the loop or arch shape
into which they have been bent.
By this means the conductors are produced in greater numbers by the same
appliances now employed, their resistance will be found to be more even, and their
capabilities of withstanding the heat of incandescence when subsequently placed in
the lamps greatly increased.
An equally convenient and expeditious means of producing the conductors
according to this Invention is as follows:-This method consists in carbonizing
paper, wood, or a similar and suitable fibrous or textile substance in narrow sheets
or strips. The carbonization is effected in the usual manner by packing a number
of the sheets in sand or in metal plates, and then subjecting them to a high
temperature in a closed retort or muffle. From these sheets the narrow conductors
with. their-gradually-enlarged-ends-aro-cut,-in-some-cases-by-a-shearing punch-but-
preferably by binding a number of separate sheets between the clamping faces of a
gauge of peculiar shape, and then cutting away all that portion of the carbon
which protrudes beyond the said gauge plates. The part left will have the shape
and size desired for the completed conductor, and these are treated in the usual
manner by being bent, fixed in clamps in the carbon gas chamber, and heated until
their resistance has been reduced to the required standard.
This process or method of treatment, though similar in many respects to the
first, has many important advantages in that the shrinkage caused by the car-
bonizing process all takes place before the conductors are formed, so that should
inequalities in the structure of the raw material exist they are compensated for in
their mode of preparation.
When the carbonized conductor are formed by the above described or any
previously known processes in which one of the steps consists in electrically
heating them in a carbonaceous gas, it rarely if ever happens that perfectly
homogeneous conductors are obtained. It will be borne in mind that the con-
ducting strips have necessarily a certain general configuration, viz., a thin narrow
central stem with enlarged clamping ends; the purpose of this is to reduce the
resistance of those portions of the conductor to which the metal clamps are

page_text: attached, in order that the latter may be protected from the intense heat which is
When therefore
produced by the high resistance of the slender incandescent stems.
the carbons are placed in the temporary clamps and electrically heated in a
carbonaceous gas for building them up and solidifying them by the deposition of
particles of carbon, it is evident that only the slender portions thereof will be
heated and receive the proper deposit, while the enlarged ends from their reduced
resistance will not be sensibly affected. And to this difference in the character of
the carbon at the ends and in the centre is thought to be due in great part the
tendency of the conductors to break off at or near the junction of the narrow and
enlarged portions when subjected to very high temperatures. With a view to
overcoming this tendency and to produce a more perfectly homogeneous and
durable conductor from carbon than has ever been done heretofore, I prepare
sheets of carbon similar to those last described. These I attach to temporary
clamps and heat to redness by an electric current in an atmosphere, one of the
constituent parts of which is carbon, using for this purpose, as in the others, a
By this means
hydro-carbon vapor or gas, such as gasoline vapor or olefiant gas.
nearly the whole strip is solidified by the deposition of the carbon, and its
resistance gradually decreased until a certain predetermined limit is reached. The
current is then shut off and the strips taken out and clamped between gauge plates,
as in the former instance, and the conductors formed from them. They are then
bent into the desired loop form, and either attached directly to the conducting
wires contained in the stopper or neck of the ordinary lamp, or a permanent set is
given to them by electrically heating them in temporary clamps in a suitable testing
chamber.
The usual manner of introducing the metal conductors into the lamp globes
adapted for use with carbons prepared as above is to seal the wires directly into
the glass; the expense attendant upon this mode of sealing led to the employment
of a ground glass plug or stopper, in which the wires were directly imbedded, the
stopper being fitted air-tight into the open neck of a transparent globe. Difficulties
in maintaining a perfect joint between the conductors and the glass, when instead
of platinum metals of an inferior grade, such as copper, are used for the conductors
are entirely overcome by the following methods of sealing, which are embraced by
and form part of the present Invention. In one instance a glass plug or stopper is
cast in a mould containing projections, which leave conical indentations in the glass
so deep as nearly to amount to actual perforations. Then by a drill applied in the
said indentations the holes are carried completely through the glass. Through the
holes thus obtained the small ends of slightly tapering wires are drawn, and the
The whole is then
spaces around the wire filled with powdered gum copal.
subjected to a comparatively high temperature, and the wires drawn through until
they completely and tightly fill the perforations. In being drawn through the
glass as through a die, the wires carry along with them a small quantity of the
copal, which forms when cold an absolutely tight joint. The stopper when
completed by the addition of a carbon conductor, which is united to the ends of the
wires, may be fitted into the open end of an ordinary lamp globe by a ground joint,
which for additional security may have a thin film of cement or gum between its
faces. The globe has an open neck into which is fitted the stopper containing the
conducting wires embedded therein, as set forth.
A lamp thus made is both durable and cheap, and may be constructed by any
ordinarily skilled workman. The exhaustion of the contined air is effected as in
the other forms, and much that involves the art of glass blowing is dispensed with
in its manufacture.
Another method of sealing the conductors into the ground plug or stopper is as
follows: The globe similar in all respects to the former is provided with an open.
and slightly flaring neck into which a stopper is fitted with a ground joint; the
stopper is perforated, as before, but in this case the perforations are made in
the mould, and are of a gradual taper from the larger to the smaller end of the
stonner.

page_text: In the holes are fitted steel plugs of corresponding shape, and of such length that
the ends project on either side of the stopper; the plugs are then fitted to the glass
by grinding until a perfectly air-tight joint is obtained, and to their inner or
smaller ends the supporting conductors are attached, while the outer ends serve as
circuit connections for a suitable switch operating to close or break the circuit
through the lamp.
This lamp consists of an enclosing globe in which are several carbons, whose
ends are united to the same mass of conducting material. Into the open neck
of the globe is fitted by grinding a stopper of glass or equivalent material;
through the stopper are formed as many conical perforations as the number of
carbon conductors requires, and into these the steel plugs are fitted by grinding,
so that the joints formed shall be perfectly air-tight. To the smaller ends of
the plugs the conductors of platinum or copper are attached in any way to
secure a good electrical contact; in the present instance they are screwed into
threaded holes in the ends of the plug. To the conductors the carbons are
clamped, their free ends being united to a small block of carbon or metal from
which a conductor leads to one of the steel plugs. From the shape of the plugs
and the manner in which they are fitted to the stopper, it follows that as the air
is exhausted from the globe in the usual way the atmospheric pressure tends to
draw them in the tighter. As an additional precaution the spaces about the
projecting ends of the plugs on the outside of the stopper are filled in with cement,
wax, or a similar substance. As a means of closing the circuit to this lamp a disc
of insulating material in which the line terminals are embedded may be used, a
projecting plug being utilized as a shaft therefor. In this case the lamp is
turned bodily to bring the plugs successively into contact with the terminals in
the disc..
The combination of two or more straight conducting strips of carbon united by
attachment to a small mass of the same or a similar material is attended with
important results due in the main to the fact that they are subjected to no strain
or tension, and are consequently more likely to last without breaking than when
bent, unless in the latter case they are prepared and, mounted with the greatest
possible care; it is also much easier to prepare them in the straight short strips.
Another method for sealing the conductors into the glass stopper is as follows:-
The copper rods or short lengths of copper wire are used; and in these are
formed a number of circular grooves or threads, either by cutting or turning them
up. Around these threaded portions when properly cleaned a small quantity of a
vitreous cement or a composition of potash silica and the oxides of iron and copper
is caused to adhere while hot, about which when hard a second layer of the same
material, but containing a smaller_proportion_of_metal_is_formed; and then_over_
this a third layer is formed of nearly pure glass. The wires with their adhering
masses of cement are then laid in a mould, and a glass plug or stopper formed
about them which is ground into the open neck of the lamp globe. The whole is
completed by the addition of the carbon conductors and the exhaustion of the
globe in the usual manner. There are wires which are milled or grooved along a
portion of their length; around this portion the layers of cement are formed, each
layer containing less metal in its composition than the one which it surrounds. The
purpose of this is to make a firin and perfect joint between the wires and the glass,
since it has been found that the greater the proportion of metal which the cement
contains the more readily it adheres to metal; but the converse is true when it is
attempted to weld it to glass. The layers are for this reason graded in order that
the surfaces presented to the metal and to the glass may be such as will readily
adhere; lugs are moulded on the stopper for its better manipulation in grinding or
removal.
For holding and conveying the current to the above or any other incandescent
lamp a chandelier or bracket is to be employed; this consists of a frame of metal
composed of two side bars insulated from each other at those points where it is held
together in mechanical union by washers of insulating material. The frame may

page_text: be either upright and secured in a vertical position to a stationary base, or may be
fixed at right angles to a wall or other support, or may depend from a support. It
is designed to do away with the usually exposed conductors by providing a path
through the bars composing it for the current between the concealed line terminals
and the lamp. The side bars are bent around near their ends and are fixed to
semicircular segmental plates; these are bound together by clamping screws between
washers of insulating material such as ebonite. The same screws serve, the one to
fix the bracket to its support, the other to clamp to the frame the base of an
electric lamp holder; the socket or holder contains the usual contact strips, the one
connecting directly by an insulated wire with one side of the frame, the other
connecting indirectly by means of circuit breaker with a spring which is in contact
with a screw, and this latter with the side bar of the lamp.
In many ways the construction of the lamp described may be changed without
departing from the spirit of the said Invention.
It is evident that the character of the lamp will depend in great measure upon
the results which it is desired to obtain therefrom. In general it will be under-
stood that the carbons prepared according to this Invention may be used in any
incandescent lamp with equal assurance of success. Again the method of sealing
may be carried out in cases not specifically described herein, as for instance the
method described of surrounding the wires with several layers of cement and then
forming a stopper about them, may be applied to the case of a lamp in which the
wires are sealed directly into the glass of the enclosing globe or receiver.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said William Robert Lake in the Great Seal Patent' Office on the
20th January 1882.
:
WILLIAM ROBERT LAKE, of the Firm of Haseltine, Lake, and Co., Patent
Agents, Southampton Buildings, London. * IMPROVEMENTS IN AND RELATING TO
ELECTRIC LAMPS OR LIGHTING APPARATUS, AND IN THE MANUFACTURE OF
PORTIONS OF THE SAME." A communication from abroad by Hiram Stevens
Maxim, of Brooklyn, New York, United States of America.
This Invention relates to incandescent lamps and to the method of manufacturing
the same, involving improvements in the means for scaling the wires into the globe
surrounding the light-giving or incandescent conductor, novel and useful processes
for the treatment and preparation of the carbon conducting strips or filaments and
certain accessory devices, hereinafter more fully described, for use with the said
lamps when completed.
According to the said Invention.
I cut out straight blanks from a sheet of paper, a block of wood, or any suitable
fibrous material, carbonize them in a closed retort or muffle, and then bend them
into the form of a loop or arch, in which form they are to be electrically heated,
and in such conditions that they will acquire a permanent set without being
injured or consumed. I cut the conducting strip from previously carbonized
sheets of fibrous or textile material, bend, and then treat them to give them a
permanent set. I carbonize and electrically heat in a carbonaceous gas or vapor
narrow sheets or strips of the same material, as above named, and then cut there-
from the conducting filament. I seal the wires into the globe by drawing them
while hot through suitable perforations in a glass stopper which is subsequently
ground into or otherwise fitted and made air tight in a lamp globe. I form the
conductors which pass through the ground glass stopper of conical steel plugs
which are introduced by grinding into perforations in a glass stopper, closing the
globe air tight. I seal the conducting wires in a glass plug or stopper by sur-
rounding them with a number of layers of a metallo-vitreous cement, each layer
containing less metal in its composition than the one which it encloses, and then
mould the glass around the portions of the wires thus covered. I use an incan-
descent conductor formed of two or more straight strips of carbon attached in the
usual manner to two metallic conductors or wires, and having their free ends
joined or attached to a mass of conducting material to form a continuous con-
ductor, and I provide a bracket or chandelier for use with the above described
lamps, so constructed as to both hold the lamps and convey the current to and
from them.
Under the first head of the said Invention the method pursued is as follows,
viz., a number of blanks are formed from sheets of fibrous material, the general
shape being that of a narrow strip with gradually enlarged butts or ends; these
strips being straight occupy but little space, so that a large number of them may
be packed into the muffle at one time and carbonized. When thoroughly charred
the strips are bent, and their ends fixed in clamps which form the terminals of
electric circuits, and are adapted to be covered by a bell glass receiver from which
the air is exhausted, and a carbon bearing gas or vapor substituted. The clamps are
arranged in pairs, and placed so as to keep the carbons in the form to which they
have been bent; a current of sufficient power is then directed through each carbon
conductor for any desired length of time, the effect of which is two fold, viz., first
to lower the resistance of each conductor to a predetermined standard, and secondly
to fix the loop or arch shape into which they have been bent.
By these means the conductors are produced in greater numbers by the same
appliances now employed, their resistance will be found to be more even, and

page_text: their capabilities of withstanding the heat of incandescence when subsequently.
placed in the lamps greatly increased.
An equally convenient and expeditious method of producing the conductors is
comprised under the second head of this Invention; this method consists in
carbonizing paper, wood, or a similar and suitable fibrous or textile substance in
parrow sheets or strips. The carbonization is effected in the usual manner by.
packing a number of the sheets in sand or in metal plates, and then subjecting
them to a high temperature in a closed retort or mulle. From these sheets the,
narrow conductors with their gradually enlarged ends are cut, in some cases, by a
shearing punch, but preferably by binding a number of separate sheets between.
the clamping faces of a gunge of peculiar shape, and then cutting away all that
portion of the carbon which protrudes beyond the said gauge plates. The part
left will have the shape and size desired for the completed conductors, and these
are treated in the usual manner by being bent, fixed in clamps in the carbon gas
chamber, and heated until their resistance has been reduced to the required
standard.
This process or method of treatment, though similar in many respects to the
first, has many important advantages; for example, the shrinkage caused by the
carbonizing, process all takes place before the conductors are formed, so that
should inequalities in the structure of the raw material exist they are compensated
for in this mode of preparation.
When the carbonized conductors are formed by the above described or other
previously known processes, in which one of the steps consists in electrically
heating them in a carbonaceous gas, it rarely if ever happens that perfectly
homogeneous conductors are obtained. It should be borne in mind that the
conducting strips have necessarily a certain general configuration, viz., a thin,
narrow, central stem with enlarged clamping ends; the purpose of this formation
is to reduce the resistance of those portions of the conductors to which the metal
clamps are attached, in order that the latter may be protected from the intense heat
which is produced by the high resistance of the slender incandescent stems. When.
therefore the carbons are placed in the temporary clamps and electrically heated
in a carbonaceous gas for building them up and solidifying them by the deposition
of particles of carbon, it is evident that only the slender portion thereof will be
heated and receive the proper deposit, while the enlarged ends from their reduced
resistance will not be sensibly affected. And to this difference in the character of
the carbon at the ends and in the centre is thought to be due in great part the
tendency of the conductors to break off at or near the junction of the narrow and
enlarged portions when subjected to very high temperatures. With a view to
overcoming this tendency and to produce a more perfectly homogeneous and
durable conductor from carbon than has heretofore been practicable, I prepare
sheets of carbon similar to those described under the second head of this Invention.
These I attach to temporary clamps and heat to redness by an electric current in
an atmosphere, one of the constituent parts of which is carbon, using for this
purpose, as in the others, a hydro-carbon vapor or gas, such as gasoline vapor or
ole-fiant gas. By this means nearly the whole strip is solidified by the deposition
of the carbon, and its resistance gradually decreased until a certain predetermined
limit is reached. The current is then shut off and the strips taken out and
clamped between gauge plates, as in the former instance, and the conductors
formed from them. They are then bent into the desired loop form, and either
attached directly to the conducting wires contained in the stopper or neck of the.
ordinary lamp, or a permanent set is given to them by electrically heating them
in temporary clamps in a suitable testing chamber.
The usual manner of introducing the metal conductors into the lamp globes.
adapted for use with carbon prepared as above described is to seal the wires directly
into the glass. The expense attendant upon this mode of sealing led to the employ-.
ment of a ground glass plug or stopper, in which the wires were directly embedded,
the stopper being fitted air-tight into the open neck of a transparent globe..

page_text: Difficulties in maintaining a perfect joint between the conductors and the glass
when, instead of platinum, metals of an inferior grade, such as copper, are used for
the conductors are entirely overcome by the following methods of sealing, which
are embraced by and form part of the present Invention :-In one instance a glass
plug or stopper is cast in a mould containing projections which leave conical inden-
tations in the glass so deep as nearly to amount to actual perforations; then by a
drill applied in the said indentations the holes are extended completely through
the glass. Through the holes thus obtained the small ends of slightly tapering
wires are drawn, and the spaces around the wire are filled with powdered gum-
copal. The whole is then subjected to a comparatively high temperature, and the
wires drawn through until they completely and tightly fill the perforation. In
being drawn through the glass as through a die the wires carry along with them
a small quantity of the copal, which forms when cold an absolutely tight joint.
The stopper when completed by the addition of a carbon conductor, which is united
to the ends of the wires, may be fitted into the open end of an ordinary lamp globe
by a ground joint, which for additional security may have a thin film of cement or
gum between its faces.
In the Drawing in Figure 1, which shews a vertical section, and Figure 2, which
shews a plan and vertical section, a lamp of this character is illustrated.
A is the globe having an open neck, into which is shewn fitted the stopper B,
containing the conducting wires D, D, which are embedded therein, as set forth,
and support the conductors E, E, one of which is shewn in side view in Figure. 3.
In Figure 2 is represented the stopper as it comes from the mould, and before the
oppositely disposed conical indentations C, C, are united by the drilling process.
A lamp thus made is both durable and cheap, and may be constructed by any
ordinarily skilled workman. The exhaustion of the confined air is effected as in
the other forms, and much that involves the art of glass blowing is dispensed with
in its manufacture.
Another method of sealing the conductors into the ground plug or stopper is as
follows, viz. The globe, similar in all respects to the former, is provided with an
open and slightly flaring neck, into which a stopper is fitted with a ground joint;
this stopper is perforated as before, but in this case the perforations are made in the
mould, and are of a gradual taper from the larger to the smaller end of the stopper.
In the holes are fitted steel plugs of corresponding shape, and of such length that
the ends project on either side of the stopper. The plugs are then fitted to the
glass by grinding until a perfectly air-tight joint is obtained, and to their inner or
smaller ends the supporting conductors are attached, while the outer ends serve as
circuit connections for a suitable switch, operating_to close-or-break-the-circuit
through the lamp.
In Figure 4 this lamp is illustrated in place and central vertical section. It
consists of an enclosing globe A, in which are several carbons D, D, whose
ends are united to the same mass of conducting material D¹. Into the open
neck of the globe A is fitted by grinding a stopper B of glass or equivalent material.
Through this stopper are formed as many conical perforations as the number of
carbon conductors requires, and into these the steel plugs E are fitted by grinding,
so that the joints formed shall be perfectly air-tight. To the smaller ends of the
plugs the conductors of platinum or copper E, E, are attached in any manner that
will secure a good electrical contact. In the present instance they are screwed into
tapped or threaded holes in the ends of the plug. To the conductors C, C, the
carbons D, D, are clamped, their free ends being united to a small block of carbon
or metal D¹, from which a conductor C¹ leads to one of the steel plugs. From the
shape of the plugs, and the manner in which they are fitted to the stopper, it
follows that as the air is exhausted from the globe in the usual way the atmospheric
pressure tends to force them in tighter. As an additional precaution the spaces
about the projecting ends of the plugs on the outside of the stopper are filled in
with cement, wax, or a similar substance. As the means for closing the circuit to
this lamp, a disc of insulating material in which the line terminals are embedded

page_text: may be used, the projecting plug E being utilized as a shaft or support therefor;
in this case the lamp is turned bodily to bring the plugs successively into contact
with the terminals in the disc.
The combination of two or more straight conducting strips of carbon united by
attachment to a small mass of the same, or a similar material, shewn in Figures 1
and 4, is attended with important results, due in the main to the fact that they are
subjected to no strain or tension, and are consequently more likely to last without
breaking than when bent, unless in the latter case they are prepared and mounted
with the greatest possible care. It is also much easier to prepare them in the straight
short strips, the general shape of which is shewn in Figure 3.
Another method for sealing the conductors into the glass stopper is illustrated
in Figures 5 to 8, Figure 5 being a vertical section of a lamp shewing the said
method of sealing the conductors in the glass stopper; Figure 6, an underside view
of the said stopper; Figure 7, an enlarged view of a portion of one of the wires
and its adhering mass of cement enclosed within the glass plug or stopper; and
Figure S, a plan of a mould hereinafter described.
In carrying into practice this part of the said Invention, copper rods or short
lengths of copper wire are used, and in these are formed a number of circular
grooves or threads either by cutting or turning them up. Around these threaded
portions, when properly cleaned, a small quantity of a vitreous cement or a compo-
sition of potash silica and the oxides of iron and copper is caused to adhere while
hot, about which when bard a second layer of the saine material, but containing a
smaller proportion of metal, is formed, and then over this a third layer is formed
of nearly pure glass. The wires with their adhering mass of cement are then laid
in a mould, and a glass plug or stopper formed about them which is ground into
the open neck of the lamp globe. The whole is completed by the addition of the
carbon conductor and the exhaustion of the globe in the usual manner. In these
Figures the wires C, C¹, are shewn milled or grooved along a portion of their
length, as at D. Around this portion the layers of cement are formed, each layer con-
taining less metal in its composition than the one which it surrounds. The purpose
of this contrivance is to make a firm and perfect joint between the wires and the
glass, since it has been found that the greater the proportion of metal which the
cement contains the more rapidly it adheres to metal, but the converse is true
when it is attempted to weld it to glass. The layers are for this reason graded
in order that the surfaces presented to the metal and to the glass may be such as
will readily adhere. The various layers are represented at E, E', and E, F, F,
in Figure 6, are lugs moulded on the stopper for its better manipulation in grinding
or removal; G represents the mould in which the stoppers are formed.
For holding and conveying the current to the above or any other incandescent
lamp, a chandelier or bracket of the kind shown in Figures 9, 10, and 11, is to be
employed. Figure 9 is an elevation partly in section; Figures 10 and 11 shew
plans of portions of the same. This bracket consists of a frame of metal composed
of two side bars C, D, insulated from each other at those points where it is held
together in mechanical unison by washers of insulating material. The frame may
be either upright and secured in a vertical position to a stationary base, or may
be fixed at right angles to a wall or other support, or, as shewn, may depend from
a support. It is designed to do away with the usually exposed conductors by
providing a path through the bars composing it for the current between the
concealed line terminals and the lamp.
The side bars C and D are bent around near their ends, and are fixed to semi-
circular segmental plates C', D¹, C", D"; these are bound together by clamping
screws G, G', between washers of insulating material, such as ebonite. The screw G
serves to fix the bracket to its support, the other screw G₁ serves to clamp to the
frame the base of an electric lamp-holder B. The lamp A is shewn inserted in
the socket or holder B which contains the usual contact strips a, b, the one con-
necting directly by an insulated wire with one side of the frame, the other
connecting indirectly by means of the circuit breaker S with a spring St, which

page_text: is in contact with the screw G¹, the latter being in contact with the side bar of the
lamp.
The construction of the above described lamps may be varied without departing
from the spirit of this Invention. The peculiar form shewn in most cases is
selected only in illustration of the several parts of the Invention involved. It is
evident that the character of the lamp will depend in great measure upon the
results which it is desired to obtain therefrom. In general it will be understood
that the carbons prepared according to this Invention may be used in any incan-
descent lamp with equal assurance of success. Moreover, the method of sealing
may be carried into practice in cases not specifically described herein; for instance,
the method described of surrounding the wires with several layers of cement and
then forming a stopper about them may be applied to a lamp in which the wires
are sealed directly into the glass of the enclosing globe or receiver.
Having thus fully described the said Invention as cominunicated to me by my
foreign correspondent, and shewn how the same may be conveniently and advan-
tageously carried into practice, I claim,-
First. The process of manufacturing carbon conductors for electric lamps, which
consists in cutting the blank from fibrous material, carbonizing the saine, bending
the carbonized strips into the desired shape, and then electrically heating them for
giving them a permanent set, as described.
Second. The method herein described of fixing a carbon strip in any form to
which it may have been bent by subjecting the same while bent to the action of
an electric current in an atmosphere of carbonaceous gas or vapor, as set forth.
Third. The method of manufacturing carbon conductors for incandescent lamps,
which consists in first cutting out and carbonizing narrow sheets of fibrous
material, then cutting or otherwise forming from these the strips designed for the
conductor; then bending and electrically heating the conductors thus formed in a
carbonaceous gas in order to equalize their resistance and impart to them a
permanent shape, as described.
Fourth. The process of manufacturing carbon-conductors for incandescent lamps
by first carbonizing thin sheets or strips of fibrous material, then heating the same
in a carbonaceous gas or vapor until their electrical resistance is reduced to a
predetermined standard; and lastly, cutting or otherwise forming from the said
sheets the conductors of the desired shape, substantially as and for the purpose set
forth.
Fifth. In the manufacture of carbon conductors of uniform quality and resistance
for use with incandescent lamps, cutting or forming the same from sheets of fibrous
material which have been exposed to the action of an electric current in carbonaceous
vapor or gas as described, and then bending and beating the said conductors as
and for the purpose specified.
Sixth. The combination with an incandescent electric lamp of a glass stopper in
which the wires are imbedded by being drawn while heated through perforations
therein with or without the use of cement.
Seventh. The method herein described of sealing the metallic conductors of an
incandescent lamp, which method consists in drawing while heated the tapering
ends of the conductors through perforations in a glass stopper, either with or
without the addition of a fusible gum or cement.
Eighth. The ground glass stopper B, Figure 1, having metallic wires D embedded
therein, A, and the conical indentations C, C, for retaining a suitable cement
or gum.
Ninth. The combination in an electric lamp of a transparent globe surrounding
the source of light, and an air-tight non-conducting plug or stopper closing the same
and containing two or more conical steel wires or plugs ground into perforations,
through the material of which said stopper is composed, and in electrical connection
with the carbon conductors, substantially as described.
Tenth. The combination with the transparent globe of an electric lamp, of a glass
stopper fitting the same by a ground joint, and containing two or more conical

page_text: steel wires or plugs ground into and passing through correspondingly shaped per-
forations in the said stopper, and suitably connected to the supporting conductors
of the carbon strip, substantially as described.
Eleventh. The combination in an electric lamp of an exhausted glass globe
surrounding the source of light, a non-conducting air-tight stopper fitted in the
same, and two or more conical steel wires or plugs ground into perforations through
the said stopper and a circuit breaker in connection with the projecting ends
of the said plugs for directing the current through them, substantially as set
forth.
Twelfth. A carbon conductor for electric incandescent lamps composed of two
independent strips of carbonaceous material joined to form a V by attachment to
a mass of conducting material, substantially as shewn and described.
Thirteenth. In an incandescent electric lamp the combination with the supporting
wires of an incandescent conductor united thereto as described, and composed of
two or more strips of carbon or equivalent composition, the ends of which are
electrically connected by attachment to a mass of conducting material, such as that
above set forth.
Fourteenth. The method of sealing wires in glass, which consists in surrounding
them previously to enclosing them in the glass with a mass of metallo-vitreous
cement composed of several layers, each containing a smaller proportion of metal
in its composition than that of the layer which it surrounds, as and for the purpose
set forth.
Fifteenth. In an electric lamp the combination with the glass endowing globe of
a ground stopper B, Figure 5, composed of a body of glass containing the wires or
conductors C, C¹, threaded or grooved, and surrounded with a mass of vitreous
cement, substantially as described.
Sixteenth, A. chandelier or bracket for an incandescent lamp, the two sides of
which bracket are insulated from each other and connected respectively with one
terminal of a line wire, and the contact strip of an incandescent lamp, whereby
the circuit may be completed through the lamp and the sides of the bracket frame,
substantially as set forth.
Seventeenth. The chandelier or bracket for electric lamps, consisting of the
conducting bars C and D, Figure 9, insulated from each other, and havingterminal
plates C, D, C, D", insulated and secured in the proper position by means of
clamping screws and washers, substantially as shewn and described.
In witness whereof, I, the said William Robert Lake, have hereunto set my
hand and seal, this Twentieth day of January, in the year of our Lord
One thousand eight hundred and eighty two.
WKUD LAKE. (L.S.)
RUB.