IMPROVEMENTS IN APPARATUS FOR ELECTRIC LIGHTING
Year: 1878

page_text: LETTERS PATENT to Richard Werdermann, of Princes Street, in the County.
of Surrey, Civil Engineer, for the Invention of "IMPROVEMENTS IN APPARATUS
FOR ELECTRIC LIGHTING."
Sealed the 19th November 1878, and dated the 21st June 1878.
PROVISIONAL SPECIFICATION left by the said Richard Werdermann at the
Office of the Commissioners of Patents on the 21st June 1878.
RICHARD WERDERMANN, of Princes Street, in the County of Surrey, Civil
Engineer. "IMPROVEMENTS IN APPARATUS FOR ELECTRIC LIGHTING."
My said Invention relates to improvements in apparatus to be used for electric
lighting, and comprises a novel arrangement of the electrodes, and improvements in
parts connected therewith.
In order that my said Invention and the principle upon which it is founded, as
well as the manner in which I carry the same into effect, may be fully understood,
I desire to make the following preliminary remarks, that is to say, when in an
electric lamp electrodes each having the same sectional area are used, the changes
at the points between which the voltaic arc is produced take place in a manner
which is well known, namely, a crater or hollow is formed in the positive electrode,
which emits the light, the crater itself being heated by the electric current to white
heat and the surrounding part to redness; the negative electrode, which, under the
influence of the current assumes the form of a cone, is only heated to redness and
emits scarcely any light.
I have found that an increase in the sectional area of the positive electrode
diminishes the light emitted by that electrode, and if the increase is continued
gradually the light from this electrode finally disappears entirely, whereas the
heating effect upon the negative electrodo in connection therewith increases, until
finally light is emitted by the same.
By increasing the sectional area of the negative electrode the heating effect upon
the same decreases proportionately to the increase of its area, until the area having
r...631

page_text: been increased sufficiently the heat disappears altogether, and consequently no
consumption or wearing away of that electrode occurs. The light emitted by the
positive electrode in connection therewith on the contrary increases in proportion
to the difference between the sectional area of the two electrodes, and instead of a
crater being formed in the positive electrode the latter assumes the form of a conc,
as formerly was the case with the negative electrode.
In carrying my said Invention into practice I propose to make use of this
manner of arranging the electrodes to produce an absolutely steady and noiseless
electric light, and to this end I provide an electrode of circular, square, prismatic,
or other convenient section, which I fit in a holder connected with one pole of either
a galvanic battery, magneto-electric machine, or any other source of electricity, or
of an induction coil or condenser, or other intermediary apparatus.
Above and in contact with the surface of this electrode, which may be either
plane or curved, I place another electrode of suitable shape, but of much smaller
section, and which is kept in a vertical or inclined position by a holder, in which it
is allowed to slide, being maintained in the same in a steady position, either by
means of friction rollers, brushes, springs, or by any other convenient means.
This electrode is kept in constant contact with the said larger electrode either by
a weight, by springs, or by any other suitable means, so that when it is slowly
consumed the electric circuit is never broken, and a steady, brilliant, and noiseless
light is emitted by the heating to incandescence of the smaller electrode at the
point of contact with the larger one.
It is advantageous to make the connection between the battery and the smaller
electrode as near as possible to the point at which the light is emitted, in order
to reduce the resistance as much as possible. The pressure between the two
electrodes must be regulated in accordance with the intensity of the electric
current.
The proportion between the sectional areas of the two electrodes I prefer to be
about one to four, which proportion is in most cases sufficient to prevent any
consumption or wearing away of the larger electrode, which is of the highest
importance.
The sectional area of the positive electrode is to be determined according to the
intensity of the electric current.
Instead of using one small electrode only two, three, or more small electrodes
converging to one point of contact with the larger electrode may be used, or two,
three, or more electrodes may be used in connection with one large electrode, in
order to produce several distinct lights.
Moreover, instead of using the smaller electrode as the upper electrode the larger
one may be placed at the top, that is to say, above the smaller one, and be allowed
to slide downwards as the smaller electrode is consumed; or the latter may be
caused by springs, counterweights, or clockwork, to assume an upward movement,
so that when it slowly burns it may always be in contact with the fixed larger
electrode at the top, the latter arrangement being very advantageous in all cases
where light is to be diffused from an elevated point, as for instance, in street lighting
and in railway carriages and stations. I may also, in some cases, make both
electrodes moveable, in order to keep them always in close contact.
Several lights may be produced from one source of electricity by either placing
the lamps in one circuit or working the same by a corresponding number of parallel
circuits.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Richard Werdermann in the Great Seal Patent Office on the 21st
December 1878.
RICHARD WERDERMANN, of Princes Street, in the County of Surrey, Civil
Engineer. "IMPROVEMENTS IN APPARATUS FOR ELECTRIC LIGHTING."
My said Invention relates to improvements in electric lighting apparatus, and
comprises various novel devices and arrangements of the parts of such apparatus,
as herein-after set forth.
In order that my said Invention and the principle upon which it is founded, as
well as the manner in which I carry the same into effect, may be fully understood,
I desire to make the following preliminary remarks, that is to say, when in an
electric lamp or lighting apparatus electrodes each having the same sectional arca
are used, the changes at the points between which the voltaic arc is produced tako
place in a manner which is well known to electricians, namely, a crater or hollow is
formed in the positive electrode, which emits the light, this crater being heated by
the electric current to whiteness and the surrounding part to redness, while the
negative electrode, which, under the influence of the current, assumes the form of a
cone, is only heated to redness and emits scarcely any light.
I have discovered that an increase in the sectional area of the positive electrode
diminishes the light emitted by this clectrode, and if this difference between the
two electrodes is very great the positive electrode ceases entirely to emit light,
whereas the heating effect upon the negative electrode in connection therewith is
increased and light is emitted by the same.
The
And furthermore, by increasing the sectional area of the negativo electrode the
heating effect upon the same is decreased proportionally to the increase of its area,
until the area having been increased sufficiently the heat disappears altogether, and
consequently no consumption or wearing away of the said electrode occurs.
light emitted by the positive electrode in connection therewith on the contrary is
increased in proportion to the difference between the sectional areas of the two
electrodes, and instead of a crater being formed in the positive electrode the
latter assumes the form of a cone, as formerly was the case with the negative
electrode.
In carrying my said Invention into practice I propose to adopt this manner of
arranging the electrodes to produce an absolutely steady and noiseless electric light,
and for this purpose I provide an electrode of circular, square, prismatic, or other
convenient form in transverse section, and which I fit in a holder connected with
one pole of either a galvanic battery, a magneto-electric machine, or any other
source of electricity, or of an induction coil or condenser, or other intermediary
apparatus.
In contact with the surface of this electrode, which surface may be either plane
or curved, I place another electrode of suitable shape, but of much smaller sectional
area, and which is kept preferably in a vertical or inclined position by a holder, in
which it is allowed to slide, being maintained in the same in a steady condition
either by means of friction rollers, brushes, springs, or hollow cylinders or tubes in
two or more parts, or by other convenient means.
This electrode during the emission of the light is kept in constant contact with
the aforesaid large electrode either by weights, springs, or the pressure of mercury
or other liquid, or by other suitable means, so that while it is slowly consumed the
clectric circuit is never broken, and a steady, brilliant, and noiseless light is emitted
by the heating to incandescence of the smaller electrode at its point of contact with
the larger one, where an infinitesimally small voltaic arc is produced, to which the
incandescence of the carbon is due. Therefore it will be seen that in my Invention
the existence of the voltaic arc is necessary for the emission of the light, as in
various other arrangements for the production of electric light, this feature forming

page_text: a very important distinction between such lights and those in which the light is
produced solely by the incandescence of the portion of an electrode between two
points of contact.
It is advantageous to make the connection between the battery or other source
of electricity and the smaller electrode as near as practicable to the point at which
the light is emitted, in order to reduce the resistance as much as possible, but the
length of that part of the smaller electrode through which the current passes must
bo so regulated that only about one half of that length will become heated
to whiteness, in order not to destroy the rollers, brushes, springs, or points of
contact.
The sectional area of the positive electrode is to be determined according to the
intensity of the electric current, in order to avoid the extension of the intensed
heating to near to the contact, where the current enters the said electrode. For
the same reason the pressure between the two electrodes must be regulated in
accordance with the intensity of the electric current, because if the pressure is too
great no voltaic are would be produced, but incandescence of the whole length of
the carbon between the points of contact (which I particularly desire to avoid) will
occur, and there will be no electric repulsion.
In the method by which I produce my light no inconvenience results from the
doposit of any impurities upon the surfaces of the carbons, therefore I am not
compelled to resort to any contrivances for giving to the large carbon any move-
ment or adjustment.
The proportion between the sectional area of the two electrodes I prefer should
not be less than about one to four, which proportion is in most cases sufficient to
prevent consumption or wearing away of the larger electrode, which is of the
highest importance, but I prefer a much greater difference between the sectional
areas of the electrodes, and generally adopt the proportion of about one to
sixty-four.
Instead of using one small electrode only, two, three, or more small electrodes
converging to one point of contact with the larger electrode may be used, or two,
three, or more electrodes may be used in connection with one large electrode to
produce several distinct lights.
Moreover, instead of arranging the small electrode to move, the larger one may
be allowed to slide downwards as the smaller electrode or carbon rod is consumed;
or the latter may be caused by springs, counterweights, clockwork, or liquid
pressure, or any other suitable contrivance, to assume an upward movement, so that
when it slowly burns away it may always be in contact with the fixed larger
electrode at the top, the latter arrangement being very advantageous in all cases
where light is to be diffused from an elevated point, as for instanco, in strect
lighting and in railway carriages and stations. I may also, in some cases, make
both electrodes moveable, in order to keep them always in close contact.
Several lights may be produced from one source of electricity by either placing
the lamps in one circuit, or working the same by a corresponding number of parallel
circuits.
The apparatus for advantageously carrying my said Invention into practise is
clearly shewn in the accompanying Drawings; but I wish it understood that I do
not limit myself to the details of the construction and arrangements shewn in these
Drawings, as many modifications of the same are possible and may be required to
adapt the said apparatus to the circumstances or conditions of each particular
case.
DESCRIPTION OF THE DRAWINGS.
Figure 1 is a vertical section of the standard of a lamp constructed according to
the said Invention; Figure 2 is a vertical section of the upper part of the same.
Figure 3 is a plan of the clamp or holding device of the large electrode; Figure 4
is a plan of the devices for supporting and guiding the small carbon, and making
the contact between the same and the wire or conductor.

page_text: Figure 5 is a side elevation shewing the adaptation of my Invention to a wall
bracket; Figure 6 shows portions of the same.
Figures 7 and 8 are vertical sections, in planes, at right angles to each other
and illustrating a modified construction of my improved lamp or light-emitting
apparatus.
Figure 9 is a horizontal section on the line x, x, Figure 7; and Figure 10 is a
horizontal section on the line y, y, Figure 8.
Figure 11 is a vertical section of portions of the said lamp.
Figure 12 is a side elevation, shewing a modification of a portion of the mechan-
ism shown in the above Figures.
Figure 13 shews an arrangement of a series of parallel circuits connected with a
machine or other source of electricity, and illustrating the division of the electric
current to supply a series of lights or lamps, and means for regulating or equalizing
the divided currents in such a manner as to ensure uniformity in the brilliancy of
the lights.
Figure 14 shews details of the devices employed in this arrangement of circuits.
Figure 15 illustrates an arrangement of parallel circuits for dividing and sub-
dividing the electric current for the lighting of strects and dwelling houses, and
the like.
Similar letters indicate corresponding parts in all the Figures.
Some of the above Figures are drawn to a larger scale than the others.
Referring to the Figures illustrating my improved lamp or light-giving device,
a is a standard or pillar, which may be constructed of metal or other suitable
material, and which supports the electrodes and the mechanism connected therewith.
b is the fixed electrode, which is considerably larger in its sectional area than the
other electrode; it may be formed entirely of carbon, or with a core or central
part of carbon surrounded by a ring or outer portion of other suitable material; b₁
is the clamp or holder in which this electrode b is secured.
I have herein-above stated that in my apparatus no movement of this large
electrode is required for the purpose of preventing the deposit of cinder thereon,
and it will be seen that no means for producing such movement are shewn; but
the clamp perinits the ready insertion, removal, and adjustment of the said
electrode. The said clamp is fitted to slide vertically on the rod or bar a', and the
said clamp may be raised and lowered on this bar and secured thereon in any
desired position. e is the movable electrode or carbon rod, which is fitted to slido
through the guides herein-after described, and is thereby kept in contact with the
disc with exactly the required pressure by the following devices: -d is a piece
fixed within the standard or pillar a, and to which are secured the small pulleys d';
over these pulleys are passed chains, cords, or bands 2, which are secured at one
end to the rod e and have attached to their other ends the weight f, which is fitted
The latter is fitted to slide
to slide upon the tube e', which encloses the said rod e.
through the fixed piece d, and in the said tube which is secured at its lower end to
the piece g fixed in the pillar a. The piece has in it a cavity or recess for the
reception of the lower end of the tube h, whose upper end is fitted within the tube
i fixed at the top of the standard a.
Tho
The electrode or carbon rod c is enclosed within the tube h, and by sliding
upward in the same is kept in continual contact with the carbon disc b.
sliding weight is accurately adjusted to preponderate over the weight to be raised
just sufficiently to keep the point of the electrode c in continual contact with the
electrode or disc b with the slightest possible pressure.
The tube i forms the aforesaid guides, which are shown detached in Figure 4.
This tube is secured by its lower end in the pillar or standard, as above specified,
and its upper portion above the line i* is divided into two parts or halves, fitted
together and kept in the proper position by pins i¹, or by other suitablo means.
Around this divided or split portion of the tube i I place the annular spring or
elastic ring 2, which is secured to the part 3 of the split tube, and through which
is passed the contact screw is, whose point bears against or enters the loose portion

page_text: of the said tube, and by the pressure of the said spring keeps the two parts of
the guide properly together, thereby forming the contact with the said movablo
electrode c while permitting the latter to move upward freely through the said
guide. This device permits a very accurate adjustment of the pressure or friction
of the guide upon the said electrode; k, l, are the wires or conductors which form
the connection between each of the said electrodes and the terminals or poles of
the machine or other source of electricity. The insulation of any of the above
parts, where required, is effected in any convenient manner.
In the modification of my apparatus, illustrated in Figures 7, 8, 9, 10, 11, I have
shewn the fixed or upper carbon spherical, instead of in the form of a disc; the
guide i has its adjustable part kept in contact with the part 3 by a spring,
which is controlled by a screw ', whose head is outside the pillar or standard a.
The pulleys d' and the guide pulleys d* are fixed on the lower or undivided part of
the tube ; the chains or cords d² are passed over the pulleys d', and behind the
pulleys d. The said chains or cords are attached by one end to the cross bar fon
which the weight is suspended, and by their. other end to the piece n, which has
at its sides small projections that fit and slide in vertical grooves formed in the
tube ; this piece n has on its upper side a small socket, which receives the lower
end of the electrode or carbon rod c. The action of the weight through the
medium of the said chains or cords and sliding piece n effects the raising of the
said electrode and keeps its point continually in contact with the fixed electrode b,
with only a slight pressure, as and for the purposes above specified. The clamp bl
is in this modification of my Invention hinged at 6, and may be turned back when
required, into the position shewn in dotted lines in Figure 8.
In Figure 12 I have shewn the adaptation of the device, ordinarily termed lazy
tongs, for the purpose of raising the movable electrode c in my apparatus. This
device, which consists of a series of bars m, rivetted together at m³, is mounted on
a fixed fulcrum pin at m*; its lower end me has suspended on it the weight m³,
and its upper end is attached to a small cup or socket m³, in which rests the lower
extremity of the electrode c. The central pins or pivots m³ are extended from the
sides of the said device, and are preferably provided with rollers, which slide in
vertical grooves formed in the pieces a* attached to the pillar a, thereby ensuring
the free movement of the said device without allowing it to deviate from a vertical
position.
The action of the weight upon the said apparatus causes the part above its
fulcrum m✶ to expand or elongate in a well-known manner, and thereby effect the
continuous upward movement of the said electrode, for the purpose specified.
I will now proceed to describe my arrangement of parallel circuits, which I have
illustrated by the diagram, Figure 13 of the Drawings. It will be understood that
this diagram does not represent the relative positions of the parts thereof as they
will exist in actual practice, but is only designed to represent graphically the
arrangement of the lights, their connection with the cables or conductors, and the
manner in which the division of the current is effected in such a manner that each
light will be produced and may be regulated or extinguished independently of the
other lights.
The machine, or battery, or other generator of electricity, is situated at any con-
venient point, as at o, and the main cables or conductors p, p, are extended from
the two poles thereof.
I may so arrange the parallel circuits in which the lights are included that the
light which is the first one or the nearest to the source of the electricity on the
positive conductor is also the first or nearest to the source of electricity on the
negative conductor. But I prefer the arrangement illustrated in the Drawings, in
which the lamp or light which is first with regard to its position on the positive
. conductor p is the last with regard to its connection with the negative conductor p².
With this arrangement the electric currents for all of the lamps or lights will have
to flow through the same distance.
This object is also effected by the arrangement shewn in Figure 15, which is a

page_text: diagram illustrating the application of my Invention to the lighting of a street and
the houses or buildings therein.
9, 9, are the lamps or lights in the aforesaid parallel circuits; q', q³, are switches
or commutators, each of which is constructed with four parts or sections, three of
which, 1, 2, 3, are formed of suitable conducting material, while the fourth part, 4,
is formed of insulating material. The part or section 1 is connected by a resis-
tance with the positive conductor; the part 2 is connected by a resistance ?"
with the positive pole of the lamp q; the part 3 is connected by a resistance 1-2
(which equals the sum of the resistance and the resistance of the lamp) to the
negative pole of the said lamp. Between this negative pole of the lamp and the
negative conductor p' the connection is made by a conductor 8 of low resistance.
When connection is made with the metallic part 3 of the key of the switch q,
between the sections 1 and 2 of the said switch, the current flows through the
lamp, and the light is produced in the same.
When connection is made between sections 1 and 3 of the said switch, the light
will be extinguished, and the current flows through the resistence to the negative
cable or conductor without affecting the brilliancy of the other lights.
When connection is male between the sections 1 and 4 of the switch, the current
which has been flowing through the said lamp is divided between all of the other
lamps and increases their intensity.
The employment of these resistances, which I term artificial or special resistances,
arranged as above described or in any other suitable manner, in connection with
one or more light emitting electrodes in the lamp, arranged in parallel circuits or in
a series, enables me to diminish any difference that may exist between the amounts
or degree of resistence to the currents acting on or passing through the various
lamps in the circuit, and thereby affords the ineans for maintaining a practically
perfect uniformity of brilliancy or intensity of all of the lights.
It is obvious that for indoor lighting switches, more complex than those above
described and provided with a certain number of resistances, may be used, in order
to diminish or increase the intensity of the lights at will.
A great advantage of the above-described method of arranging a number of lights
in parallel circuits, in combination or connection with my improved lighting
apparatus, is the possibility of producing the lights by weak currents or currents of
low tension, thereby avoiding all difficulty of insulation of the cables throughout
great distances.
In Figure 15, t, t, t, t, t, t, represent sub-divided parallel circuits connected with
the main circuit p, p²; u, u, u, indicate street lamps or lights.
My improved apparatus may be readily and conveniently adapted to the existing
street lamp posts or pillars.
As will be seen from the foregoing explanation, the electric light of my improved
apparatus is not due to what is termed incandescence but to the production of a
voltaic arc, which, though infinitesimally small, exists and is due to the infini-
tesimally small distance which separates the electrodes, and to the phenomenon of
the repulsion or repulsions exerted by the adjacent or contiguous elements of tho
voltaic or electric current.
The best effect of the light can only be obtained by observance of the proportions
between the areas of the electrodes, the distance between the points of contact, the
pressure, and the strength or intensity of the current, as above explained. These
proportions cannot be exactly stated for all cases, but the proper regulation of the
same will always be indicated by the appearance of the light, and the required
adjustinents may be made in accordance with such indications.
Having thus fully described my said Invention, and the manner of performing the
same, I wish it understood that I do not claim as a novel feature of my Invention
a device or apparatus of which the only peculiarity is the difference between the
dimensions of the two electrodes, as I am aware that the employment in an electric
light apparatus of two electrodes, one of which is larger than the other, has been
disclosed in the Specification of Patents existing long before the date of my Invention.

page_text: I further wish it understood that I do not claim or use any arrangement or com-
bination of parts that will cause the emission of light by the incandescence or
heating to whiteness of an electrode or conductor between two points of contact,
except such a degree of incandescence as may be due to the voltaic arc, but I
claim,
First. For the production of electric light, the employment of a device or
apparatus wherein there are two electrodes, the sectional area of one of which is
larger than that of the other, and wherein the pressure that keeps the two electrodes
in contact, and the distance between the points of contact are so proportional to
each other and to the sectional area of the said electrodes, and to the strength and
tension of the electric current, that the light is emitted by the production of a
voltaic arc infinitesimally small at the point of contact between the two electrodes.
Second. The apparatus illustrated in Figures 1, 2, 3, 4, of the Drawings, or any
of the modifications thereof, and comprising the fixed and moveable electrodes, one
of which is of larger sectional area than the other, and the mechanism whereby the
movable electrode is kept in contact with the fixed electrode under such conditions
that the light may be emitted by the production of an infinitesimally small voltaic
are at the point of contact of the two electrodes without causing incandescence of
the smaller electrode throughout its length or distance between its two contact
points, whereby the inconvenience arising from the fusion of the carbons and
deposit of cinder or other matter on the fixed electrodes are avoided, as above set
forth.
Third. The apparatus or arrangements comprising the series of parallel circuits,
in connection with my improved lamps or otlier suitable lighting devices, with or
without artificial or special resistances, in the manner illustrated and described in
connection with Figures 13 and 14 of the Drawings, whereby I am enabled to
effect the division of the electric current to produce any desired number of lights
in connection with one battery or other source of clectricity, in such a manner that
each one of such lights may be regulated or extinguished without affecting any or
either of the other lights, and whereby I am enabled to employ a weak current or
current of low tension, as and for the purposes specified.
Fourth. In a circuit including a number or series of lights, the employment of
artificial or special resistances in connection with the electrode or electrodes, by
which the light is emitted in such a manner that the effect of the difference be-
tween the resistances of any or all of the lights in the circuit will have no appre-
ciable or apparent effect upon the electric current, and the lights may therefore be
maintained with uniform intensity or brilliancy.
In witness whereof, I, the said Richard Werdermann, have hereunto set my
hand and seal, this Twenty-first day of December, in the year of our Lord
One thousand eight hundred and seventy-eight.
RICHARD WERDERMANN. (L.S.)