IMPROVEMENTS IN AND RELATING TO REGULATING DEVICES FOR ELECTRIC LAMPS
Year: 1885

page_text: I WILHELM LAHMEYER of 13 Brühlstrasse, Hanover, Germany, Candidate of
Mathematics do hereby declare the nature of my invention for "IMPROVEMENTS
IN AND RELATING TO REGULATING DEVICES FOR ELECTRIC LAMPS "3 to be as
follows:-
This invention relates to regulating devices for electric arc lamps, in which the
expansive power of gases developed by electrolysis is used as the motive power for
the regulation.
The various modifications of which the mechanism constituting the said Inven-
tion is susceptible have all in common the characteristic that any deviation of the
main current in an hermetically closed electrolytic cell gives rise to the generation
of gases which cause a rigid part, connected directly or indirectly with the carbons,
to continually advance in proportion as the latter are consumed. It will be
observed that by a different arrangement and choice of the operative elements,
a great number of modifications of the devices hereinafter described can be made
without any difficulty.
The principal constituent parts of a lamp, in which the gases are generated by
electrolysis, comprise a cell containing the decomposing substance or electrolyte and
the plates of the electrodes, which are in a shunt, and cause, when a current passes
through them, the evolution of gases. A vessel filled with a liquid, for instance
glycerine, is, through a tube, in communication with the cell containing the
electrolyte. With the said vessel communicates a vertical tube in which moves
a piston or float connected directly with the lower carbon-holder. The current
forms the voltaic arc in the main branch. With both poles of this arc is connected
a shunt circuit in which a resistance is included, whereby the strength of the
current in the shunt is so regulated as to cause the evolution of gas to such an
extent that the lower carbon is always raised as much as is burnt away from both
carbous. In a lamp of this kind which burns with a current of 8 ampères and the
piston of which is 4 square centimetres in section I have employed a resistance
equal to about 1000 ohms. Accordingly the strength of current in the shunt
amounted to only about 0.05 ampères. Such a slight loss of current for effecting
the regulation is a characteristic feature of this regulating device, in which the
regulating power is produced by the generation of gas in electrolysis.
Dina 1171

page_text: When the carbons are at too great a distance apart the increase of the current in
the shunt occasions an augmented generation of gas, and the consequent rising of
the piston shortens the voltaic arc. Too small a distance between the carbons in a
similar but inverse manner, causes a weaker current in the shunt and a slower
ascent of the piston than corresponds with the consumption of the carbons, until
the normal are has been again reached. The slightest changes in the length of the
arc are accordingly by these means compensated for, in a manner imperceptible to
the eye, by the more or less rapid generation of gas.
The formation of the voltaic arc can be effected by a device which causes the
carbons, after the circuit is closed, to approach rapidly and to separate again a
little after contact. Electro-magnetic effects of the current can be utilized for this
purpose in the known manner.
The voltaic arc can be formed either above the regulating mechanism as described,
or below the same.
When the arc is to remain in the same place, I attach a cord to the top of the
vertical tube which communicates with the vessel containing the liquid, and which
is provided with the piston connected with the lower carbon-holder, which cord
passes around a pulley on the piston-rod and over other pulleys on the frame to
the upper carbon-holder, to which it is tied. The motion of the lower carbon-
holder is in this manner transmitted, in the reverse direction, to the upper
carbon-holder, the speed of movement of which is doubled. If the weight of
either carbon-holder is such that the two are maintained in equilibrium, no
appreciable pressure is exerted by the said piston upon the liquid, whereby the
latter is prevented from passing above the piston.
For maintaining the position of the are constant, other suitable devices of known
construction for connecting the two carbons can be employed, but two electrolytic
gas-producers placed one behind the other or parallel to one another can also be
used, one of which causes the motion of the lower carbon and the other that of the
upper carbon. The pistons and cylinders must be of unequal sections inversely
corresponding to the unequal consumption of the carbons.
A constant position of the arc is also obtained by dividing the electrolytic cell
included in the shunt by a porous partition or wall into two compartments. If
water is used as an electrolyte, the volume of hydrogen separated is double that
of oxygen. As this proportion of volume corresponds with the proportion in which
the two carbons are burned away, the motion of the positive carbon can be effected
by the expansive power of the hydrogen evolved, and the motion of the negative
carbon by that of the oxygen.
It is possible to adopt other methods of arranging the circuits than by branching
off a shunt from the two poles of the voltaic arc, For instance from a point of the
main circuit a conductor might pass to a point in the shunt circuit and a gas-
apparatus of the class described might be arranged at any place in this third
branch. As, in this place, the strength of the current would be a function of the
resistance of the voltaic arc, a motion of the piston suitable for the automatic
regulation might also be obtained. The gas-apparatus would then take the place
of the galvanometer in a Wheatstone Bridge.
With open lamps, a liquid congealing with as great difficulty as possible is used
as an electrolyte. An arrangement may also be made in which a compensation
piece (usually made of two strips soldered upon one another and consisting of two
metals, differing as much as possible in their expansions by heat) effects a contact
by bending at a certain low temperature, so that the current flows into conductors
and heats them, the latter being placed in the liquid or in proximity to it. The
motion of the column of a mercurial thermometer, in the tube of which are located
two electrodes, may also be used for effecting a change of the current at a definite
temperature.
In another modification of the lamp, I make use of auxiliary electro-magnetic
devices for forming the arc and maintaining the distance of the carbons apart,
between certain limits. The operation of these devices is as follows:-In order to

page_text: cause the carbons, after the entrance of the current, to approach each other rapidly,
the current is sent in a direct line through the electrolytic cell, so that a very rapid
evolution of gas takes place; by opening a valve of the vessel containing the gas
the piston in the vertical tube or cylinder moves back, whereby the formation of
the voltaic arc is effected. By the employment of a direct short circuit between
the poles of the cell, the generation of gas is almost caused to cease if the carbons
move too near each other.
In this arrangement, the resistance employed in the shunt circuit is in the form
of a coil surrounding an iron core, and with the latter constitutes an electro-
magnet. There is, moreover, in the main circuit a small electro-magnet. By
attracting the lower armatures, each of which is fixed to a lever turning upon an
axis, these electromagnets actuate the aforesaid valve of the vessel containing the
gas, which valve is carried by an arm of the lever of the lower armature of an
electromagnet in the shunt, so that when this armature is attracted, the valve is
closed. A projection is provided on the lever of the armature of the electromagnet
in the main circuit whereby the said lever closes the valve when the armature
connected with it is not attracted. This second armature over-balances the first
armature. The valve is, therefore, closed when no current flows through the lamp,
and is open only when the lower armature of the electro-magnet in the main
circuit is attracted, and that of the electromagnet in the shunt is not attracted.
The purposes of the remaining parts of the modified form of apparatus will be
rendered clear when the operation of the lamp is considered. Armatures on the
upper ends of the said electro magnets are pressed by spring strips against stops
when the armatures are not attracted. All these parts are fastened to the frame
of the device, and insulated therefrom.
If the circuit is closed when the carbons do not touch each other, the upper
armature of the electromagnet in the main circuit bears against its stop and the
current passes through the cell which offers only the resistance of the electrodes―
CoLequently a considerable generation of gas takes place and the piston rises
rapidly in the vertical tube or cylinder. As soon as the carbons come into contact,
the electromagnet in the main circuit is energized and attracts its upper armature,
so that the contact of the latter with its stop is interrupted. The lower armature
of the electromagnet in the main circuit is also attracted, the valve of the gas-vessel,
therefore, opens, whereby some gas escapes therefrom causing the piston to sink
a little, and the arc to be formed. The current in the coil of the electro-magnet
included in the shunt circuit now becomes strong enough to attract its lower
armature, whereby the said valve is closed. The power of the spring strip to
which the upper armature of the electromagnet in the shunt is attached is so
regulated by an adjusting screw that this armature is not attracted when the
distance between the carbons is less than the desired limit, that is, when a
correspondingly smaller current flows through the resistance in the shunt. This
resistance is such that the generation of gas takes place a little more rapidly than
corresponds with the consumption of the carbons. The lamp therefore burns in
such a manner that after a certain time the distance between the carbons becomes
too small. The electromagnet included in the shunt then releases the upper.
armature (whereas its lower armature is released only when the carbons touch each
other) and a short circuit is formed around the cell whereby the passage of the
current and the evolution of gas at the electrodes are almost caused to cease, so
that the carbons burn without being brought nearer to each other. As soon as the
distance has increased to a little over the intended length, the upper armature of
the electromagnet in the shunt is again attracted, the short circuit around the cell
is opened, and the generation of gas recommences.
These variations in the distance are very slight in comparison with the spaces of
time during which they take place.
The movement of the carbons thus takes place so slowly that it cannot be
perceived by the eye,

page_text: It will thus be understood that if the arc is first formed too large it will become
gradually smaller, if it is formed too small it will become gradually larger, and
then always keeps within the proper limits. When the lamp is extinguished the
upper armature of the electro magnet in the main circuit immediately makes
contact with its stop, consequently the current passes through the cell and the
above described operation commences again.
The resistance of the shunt circuit and of the electrodes in the electrolytic cell is
preferably made equal to that of the voltaic arc, in order to avoid interruptions in
a lamp affecting other lamps in the same circuit.
If the piston in the vertical tube or cylinder communicating with the vessel for
the gas is raised to its highest position, a short circuit is mechanically formed in
the main branch, a projection connected with the lower carbon-holder striking
against a projection on the upper carbon-holder.
The spring strips holding the two upper armatures of the electro magnets can if
desired be replaced by spiral springs.
The construction of the lamp renders it fit for any strength of current and for
any illuminating power.
According to a further modification the regulating device is arranged above the
voltaic arc.
The upper carbon holder is suspended from two cords, the first of
which passes over three pulleys connects it with the lower carbon holder, the other
cord passing over two of the said pulleys and around a pulley on an expanding and
contracting chamber is attached to a fixed point. For this purpose one of the
pulleys has two grooves.
The said chamber is preferably in the form of bellows, and it can be substituted
for the cylinder and piston in the other arrangements. This is of special advantage
in cases where by the connection of cords, or' by lever mechanism or gear wheels, a
small motion of the part actuated by the pressure of the gas is increased and
transmitted to the carbons.
The
The upper carbon is overbalanced relatively to the lower, and accordingly the
two move at the rate which the expansion of the said chamber admits of. The
resistance in the shunt is, as in the modification of the lamp before described
sufficiently small for the generation of gas to take place to such an extent that the
carbons approach closer than the distance required to maintain the arc.
generation of gas is then immediately interrupted by the operation of electro-
magnets, in a shunt similar to that described in connection with the last described
arrangement. In this manner the contact of the carbons in this lamp is rendered
impossible. For rapidly approaching the carbons, when the circuit is closed and
the arc is extinguished, a small electromagnet enclosed in the main circuit also
causes the shunt resistance to be cut out and accordingly a more rapid generation
gas to take place.
of
In order to protect the armatures forming the contact from dust and the like,
these parts can be enclosed in a small box. These electromagnetic contact devices
correspond with those described in the last arrangement.
In the tube connecting the elastic chamber with the electrolytic vessel is inserted
a valve for enabling the gas to escape when the carbons are replaced.
The expansion of the said chamber may if desired be effected by the admission
of liquid into the same upon which the gas exerts its pressure.
If only a few fine openings are provided for the admission and discharge of the
liquid, unsteady movements of the chamber cannot occur, even where it is
considerably shaken a lamp so constructed can therefore advantageously be used
for locomotives, ships and the like.
For lifting the carbons a device is connected with one of the carbon holders
consisting of strips of two metals differing in their expansion under the influence
of heat, for instance, zinc and iron, which strips are soldered upon one another and
are of the form of either a bow or a serpentine so that the heat during the passage
of the current causes a diminution of the distance between their ends, that is to
say an ascent of the carbons. Such metallic device can also be formed of a greater.

page_text: or smaller number of double metal strips composed in any suitable manner, and
can moreover be arranged in another part of the mechanism, for instance as a
carrier for one of the pulleys, but it must always be in the main circuit. This
device can likewise be employed with the other regulating apparatus.
In some case I provide means for obtaining through the electrolytic expansion
of gas the movement of the floating piston, in this case liquid is forced into a
vessel and thereby causes a float in the same to ascend; or the liquid descends
into a hollow float and causes this to sink.
In order to deprive the gases escaping from the electrolytic cell of their humidity,
a drying apparatus of any known construction can be used in the place of the
tube connecting the cell with the vessel for the gas.
Although the arrangement of the decomposing apparatus in a branch circuit
is most suitable, it can if desired be inserted in the main circuit in combination
with an electro-magnet which by the formation of a short circuit around the cell
deprives the latter of the current as soon as the distance between the carbons
becomes too small. In this case the approach of the carbons takes place during
the rapid generation of gas.

page_text: Electric Lamps.
I, WILHELM LAHMEYER, of 13 Brühlstrasse, Hanover, Germany, Candidate of
Mathematics do hereby declare the nature of this invention and in what manner
the same is to be performed, to be particularly described and ascertained in and
by the following statement:-
This invention relates essentially to regulating devices for electric arc lamps, in
which the expansive power of gases developed by electrolysis is used as the motive
power for the regulation.
The mechanism constituting the said invention is susceptible of various modi-
fications, all of which possess the common characteristic that any deviation of the
main current in a gas-tight electrolytic cell gives rise to the generation of gases
which cause a rigid part directly or indirectly connected with the carbons to
continually advance in proportion as the latter are consumed. By different
arrangements and selections of the operative elements a great number of modi-
fications can be easily made.
In the accompanying drawing
Figure 1 shows, in diagram, the simplest form of regulating apparatus con-
structed according to my invention.
Figures 2 and 3 show arrangements of the regulating mechanism for retaining
the focus of the arc constantly at the same place.
Figures 4 and 5 show lamps having accessory devices for the formation of the
voltaic arc.
Figure 6 represents my improvements applied to a suspension lamp.
Figure 7 is a diagram shewing an arrangement of the circuits after the manner
of the Wheatstone bridge.
In all the figures the main circuit is indicated by feathered arrows, and the
shunt circuit by unfeathered arrows. Moreover, the source of electric power,
which is generally a dynamo-electric machine, is indicated by the circle D, and any
resistances which may be necessary are designated by R. These devices serve in
proportion to the gradual production of the expansive power, to gradually feed the
carbons in a manner which is not perceptible to the eye.
The main parts of a lamp regulated by the electrolytic generation of gas are
represented in Figure 1. K is a vessel which contains the decomposing substance
and the electrodes g. The plates forming these electrodes are in a shunt circuit
and when the current passes through them, cause the evolution of gases. A vessel G
filled with a liquid, for instance glycerine, is placed in communication with the
cell K through a tube I. With the vessel G communicates the tube H, in which
moves a piston or float which is in direct connection with the lower carbon holder.
The current forms the voltaic arc in the main circuit, which is indicated by
feathered arrows. With the two poles of the arc circuit is connected a shunt
circuit indicated by unfeathered arrows. In this shunt circuit is placed the
resistance R, by means of which the strength of the current in the said shunt

page_text: circuit is so regulated as to cause the evolution of gas to such an extent that the
lower carbon is always raised as much as the length burnt away from both
carbons. In a lamp of this kind which burns with a current of 8 ampères, and
the piston of which was 4 square centimetres in section, I have employed a
resistance equal to about 1000 ohms. Accordingly the strength of current in the
shunt was only about 0-05 ampères.
When the carbons are at too great a distance apart, the increase of the current in
the shunt occasions an augmented generation of gas, and the consequent rising of
the piston, thereby shortening the voltaic arc. In a similar but inverse manner too
small a distance between the carbons causes a weaker current in the shunt circuit
and a slower ascent of the piston than corresponds with the consumption of the
carbons, until the normal arc has been again reached. The slightest changes in the
length of the arc are accordingly compensated for by the more or less rapid
generation of gas, in a manner imperceptible to the eye.
The device which effects the formation of the voltaic arc, by the carbons being
caused to approach rapidly after the circuit is closed and to separate again a little
after contact, is not represented in Figure 1 and the following two figures.
Electro-magnetic effects of the current can be utilized for this purpose in the
known manner.
The following figures show-mostly in diagram-modifications of the regulating
device illustrated in Figure 1.
The signs used in Figure 1 are retained for analogous parts in the several
figures.
Figure 2 shows the lamp arranged in such a manner that the focus of the are
constantly remains in the same place. From the point o at the top of the tube H
passes a cord 8 around a pulley on the piston-rod, and around other pulleys fixed
to the frame of the lamp to the upper carbon-holder, to which latter it is tied at o¹.
The motion of the lower carbon holder is thus transmitted at twice the speed and
in the reverse direction to the upper carbon holder. If the weight of the two
carbon holders is such that they are in equilibrium, no appreciable pressure is
exerted by the piston c upon the liquid, whereby the latter is prevented from
passing above the piston.
For maintaining the position of the arc constant, other suitable devices of known
construction for connecting the two carbons can also be employed.
Two electrolytic gas producers connected in parallel or in series, can also be
used; one of them causing the motion of the lower carbon, and the other that of
the upper carbon. The pistons and cylinders must be of unequal sections inversely
corresponding to the unequal consumption of the carbons.
As shown in Figure 3 a constant position of the arc is obtained by dividing the
electrolytic cell included in the shunt into two compartments, by the porous
partition d. If water is used as an electrolyte, the volume of hydrogen separated
is double that of oxygen. As this proportion of volume corresponds with the
proportion in which the two carbons are burned away, the motion of the positive
carbon can be effected by the expansive power of the hydrogen evolved, and in
the same manner the motion of the negative carbon by that of the oxygen. It is,
of course, possible to adopt other arrangements of circuits than by taking a shunt
from the two poles of the arc circuit.
Thus, for instance, the cell can be placed in the diagonal connecting the arms of
a Wheatstone's bridge, the four side branches of which include the voltaic arc and
three constant resistances. These constant resistances are so chosen that the
current disappears in the diagonal when there is a suitable resistance of the
voltaic arc.
12:3
This arrangement of the circuits is represented in diagram by Figure 7-
q indicates the cell arranged in the diagonal, the voltaic arc, and w¹, w³, w³ con-
stant resistances, which can at the same time be used as solenoids. When =
the current disappears in the diagonal. When the resistance of 1 has sufficiently

page_text: increased by the consumption of the carbons that the difference of tension occurring
between the ends of the diagonal, that is between the points 2 and 3, is greater
than the polarization of the cell, a current flows through the diagonal. The
generation of gas then takes place at q, which gas, as described with regard to the
other figures, is used for the approach of the carbons.
With open lamps a liquid congealing with as great difficulty as possible is used
as an electrolyte, "for instance slightly diluted acid."
Figure 4 represents a lamp, analogous to Figure 1 and provided with auxiliary
electro magnetic devices for forming the arc and maintaining the distance between
the carbons within certain limits.
The operation of these devices is as follows:-
1). In order to cause the carbons to approach rapidly, the current is sent in a
direct line through the electrolytic cell, so that a very rapid evolution of gas takes
place; 2) by opening the valve the piston c is caused to move back, and the
voltaic arc is formed; and 3) by the formation of a direct short circuit between
the poles m and n of the cell, the generation of gas is caused almost to cease, if the
carbons move too near to each other.
In this arrangement the resistance R in the shunt is in the form of a coil
surrounding an iron core, and with the latter forms an electro magnet E. There is
moreover in the main circuit a small electromagnet E¹. By attracting their
armatures a and a¹ each of which is fixed, in the manner shown to a lever turning
upon an axis, these electromagnets actuate the valve v, which is carried by one arm
of the lever carrying the armature a. Thus when the armature a is attracted the
valve is closed.
A projection is provided on the lever of the armature a¹, which projection
closes the valve when the armature is not attracted. The armature al counter-
balances the armature a. The valve is therefore closed when no current flows
through the lamp, and the valve is open only when the armature a¹ is attracted
and the armature a is not.
The purposes of the remaining parts will be rendered clear when the operation
of the lamp is considered.
The upper armatures 6 and 6¹ of the electromagnets are pressed by the springs g
and g', fastened to the blocks e and e', against the stops & and d when the
armatures are not attracted. All these parts are fastened on the frame of the
lamp and insulated therefrom. If the circuit is closed when the carbons do not
touch each other, then the armature 6¹ bears against the stop d¹ and the current
passes through P, O, d¹, b¹, e¹, m, g, n, N through the cell, which offers only the
resistance of the electrodes. Consequently a considerable generation of gas takes
place and the piston c rises rapidly. As soon as the carbons touch each other the
electromagnet El is energized and attracts the armature b¹, so that the contact of
the latter with its stop d¹ is interrupted. The armature a¹ is also attracted, there-
fore the valve v opens, and a little gas escapes, causing the piston c to sink and
form the arc. The current in the electromagnet E.now becomes strong enough to
attract the armature a and the valve closes. The power of the spring g is so
regulated by the screws that the armature b is not attracted when the distance
between the carbons is less than desired, that is when a correspondingly smaller
current flows through the resistance R. This-resistance is such that the generation
of gas takes place a little more rapidly than corresponds with the consumption of
the carbons. The lamp therefore burns in such a manner that after a certain time
the distance between the carbons becomes too small. Then, however, the electro-
magnet E releases the armature b (whereas the armature a is released only when
the carbons touch each other) and the short circuit m, e¹, b¹, e, b, d, n is formed.
The passage of the current through the gas generator and the evolution of gas are
thus almost caused to cease, so that the carbons burn away without being brought
nearer to each other. As soon as the distance has increased a little beyond the
desired length, the armature b is again attracted, the short circuit around the cell
is opened, and the generation of gas recommences. These variations of the distance

page_text: between the carbons are very slight in comparison with the spaces of time during
which they take place. The movement of the carbons thus takes place so slowly.
that it cannot be perceived by the eye.
It will thus be understood that if the arc is too large, it will become gradually
smaller; if it is formed too small it will become gradually larger, and then always
keep within the proper limits.
When the voltaic arc is extinguished the. contact of the armature b¹ with its
stop & immediately takes place, the current then passes directly through the cell
and the above described operation commences again.
The resistance of the shunt circuit m n and of the electrodes q is preferably.
made equal to that of the voltaic arc, in order to obviate interruptions in one lamp
affecting other lamps in the same circuit. When the piston c is raised to its
highest position, a short circuit is mechanically formed in the main circuit, a
projection connected with the lower carbon holder striking against the projection
on the upper carbon holder (neither being shewn).
The spring strips g g¹ can, if desired, be replaced by spiral springs.
The construction of the lamp renders it fit for any strength of current and for
any illuminating power.
'
Whilst in the preceding lamps the generation of gas is made dependent on the
resistance of the voltaic arc, in the latter case a relay is employed to cause the
generation of gas to be increased or diminished. Instead of an electromagnet a
solenoid can be used for the relay, which solenoid acts upon a core which is movable
in the same.
In order to adapt the lamp for connection in parallel, the coil of the
relay is placed in the main current. By the combined action of a main circuit coil
and a shunt circuit coil upon a core, a differential relay is obtained, which enables
the lamp to burn when connected in parallel as well as when connected in series.
In case it is not required to use the resistance beside the cell as the coil of an
electromagnet or as a solenoid, and the cell with the resistance are in a separate
shunt circuit, the said circuit of the cell can be opened by the motion of the relay
armature for interrupting the generation of gas.
Figure 5 shews a lamp in which the regulating device is arranged above the
voltaic arc in the ordinary manner. The upper carbon holder is suspended from
two cords 88 and 81, 82, the first of which, passing over the three pulleys r¹ 73 +3
connects it with the holder of the lower carbon; the other, passes over the
pulley and around the pulley r on the expanding and contracting chamber C,
and is attached to the fixed point o. The pulley r¹ accordingly has two grooves.
In case the chamber consists, in the manner illustrated, of single cells which are
made of india-rubber, it extends, when the internal pressure increases extraordi-
narily, in the direction of its axis. For this reason such a chamber can replace the
piston and cylinder in the other arrangements. This is of special advantage in
cases where, by the connection of cords, or by lever mechanism or gear wheels, a
small motion of the part actuated by the pressure of the gas is increased in being
communicated to the carbons.
The upper carbon is counterbalanced relatively to the lower, and accordingly the
two move at the rate which the expansion of the vessel C admits of. The resist-
ance R is, as in the modification of the lamp herein before described, sufficiently
small for the generation of gas to take place to such an extent that the carbons
approach each other closer than the distance required to maintain the arc.
generation of gas is then immediately interrupted by the operation of the electro-
magnets in the shunt, which is similar to that described with reference to Figure 4.
In this manner a contact of the carbons in this lamp is rendered impossible.
The
For rapidly approaching the carbons when the circuit is closed and the arc is
extinguished, a small electromagnet inserted in the main circuit also causes the
shunt resistance to be cut out, and accordingly a more rapid generation of gas
takes place.
In order to protect the armatures forming the contact from dust and the
like, these parts can be enclosed in a small box B. These electro-magnetic contact

page_text: devices entirely correspond with those shown in Figure 4 and are merely
indicated.
v is a valve for enabling the gas to escape when the carbons are renewed.
For lifting the carbons I employ the apparatus shown at F, Figure 5º. This
apparatus consists of strips & and e, of two metals differing in their expansion under
the influence of heat, for instance zinc and iron. These metals are soldered upon
one another in the manner illustrated. The black strips are those which expand
more by heat, accordingly the heating during the passage of the current effects a
diminution of the distance between the board p and the socket t, and the consequent
ascent of the carbons.
This apparatus is not made, as shown in the diagram, of a few single bows, but
formed of as many as possible, so as to attain as long motions as possible. This
apparatus can also be arranged at some other part of the mechanism, for instance
as a carrier for one of the pulleys, but it must always be in the main circuit. This
bow device can also be employed with the other regulating apparatus.
Figure 6 shows a lamp in which, in order to obtain a low superstructure, the
vessel with the cylinder and piston is arranged below the voltaic arc.
The lamp
contains the contact apparatus described with reference to Figure 4. E is the
electromagnet in the shunt circuit and E' the electro magnet in the main circuit.
The latter fulfils moreover the function of forming the voltaic are by attracting the
armature a. This armature a enters the core of the magnet El and carries on the
stem w the plate x which prevents the armature from falling too far. The current
conductors are not shown, they are similar to those shown in Figure 4. y y¹ are
pieces of insulating material.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is :-
First-In an electric arc-lamp, the arrangement of an electrolytic cell in a shunt
from the main circuit, the gases generated in which cell act on and move a piston
in a cylinder communicating with the cell, or cause the expansion of an elastic
chamber communicating with the cell, which motion is utilized for moving the
carbons towards each other by the rigid or articulated connection of the said piston
or elastic chamber with one or both of the carbons; the quantity of gas generated
being made dependent on the distance between the carbons; either by arranging
the electrolytic cell in a shunt around the voltaic arc, which shunt is provided with
a resistance determining the intended average amount of this shunt current, or by
arranging the cell in the diagonal of a Wheatstone bridge whose four arms or
branches contain respectively the voltaic arc, and, three constant resistances; or by
causing the intermittent current in the cell by the motion of the armature of a relay
making or breaking a contact.
Second-In regulating apparatus for electric arc lamps, the combination of a
vessel K containing an electrolytic bath and electrodes q, a communicating
receptacle G, and the cylinder H having the piston c, substantially as described
with reference to Figure 1.
Third: In a regulating apparatus for electric arc lamps, the combination of the
vessel K containing a decomposing device q, the vessel G, the cylinder H having
the piston c, and the cords for transmitting the motion of the piston to the upper
carbon-holder, substantially as described with reference to figure 2.
Fourth In a regulating apparatus for electric arc-lamps, the combination of
the vessel K which is divided by the porous partition into two parts and has the
decomposing device q, the pistons c and c¹, the resistance R, and the cord & for
connecting the carbon with the piston c¹³, substantially as described with reference
to Figure 3.
Fifth-In a regulating apparatus for electric arc-lamps, the combination of the
decomposing device q in the vessel K, the communicating vessels G, the cylinder H
having the piston c, the electro magnets E, E¹, and the spring armatures b, b¹,

page_text: actuated by the latter, and the valve
described with reference to figure 4.
with the armatures a a¹, substantially as
Sixth In a regulating apparatus for electric arc-lamps, the combination of the
decomposing device q in the vessel K, with the extensible vessel C, the cords or
chains 88 connected therewith, and the electro magnets E E¹ having the
armatures a a¹.
Seventh-In a regulating apparatus for electric arc-lamps, the combination of
compensating strips ze through which the current passes, with a carbon holder,
substantially as described with reference to figure 5º,
Eighth In a regulating apparatus for electric arc-lamps, the combination of the
vessel K. having the piston c and the valve v below the voltaic arc, and connected
through a tube I with the decomposing device q above the voltaic arc, of the electro
magnets E E¹ and the spring contacts 6 6¹ and armature a which are actuated by
the said electromagnets, the stem w of the armature extending into the core of the
electromagnet E¹, and being protected from falling by a disc a, substantially as
described and illustrated in figure 6.