IMPROVEMENTS IN ELECTRIC ARO LAMPS
Year: 1883

page_text: LETTERS PATENT to James Grieve Lorrain of 2 Victoria Mansions in the
City of Westminster Consulting Engineer for an Invention of " IMPROVEMENTS
IN ELECTRIC ARO LAMPS"
PROVISIONAL SPECIFICATION left by the said James Grieve Lorrain at the
Office of the Commissioners of Patents on the 11th January 1883.
JAMES GRIEVE LORRAIN of 2 Victoria Mansions in the City of Westminster
Consulting Engineer "IMPROVEMENTS IN ELECTRIC ARC LAMPS
My invention relates to improvements in electric are lamps whereby a lamp of
great simplicity and efficiency is obtained
In carrying my said invention into practice I employ a frame consisting of two
guide rods carrying a plate or bar at its top for the attachment of the terminal
screws of the lamp and a device for suspending the said frame. At or near their
bottom the said guide rods carry a second plate or bar forming a support for the
lower carbon which according to this invention may or may not be fixed The
guide rods may be strengthened or made more rigid by means of rings or
connecting parts or other similar devices of metal or other material placed at
intervals along their length care being taken to prevent short circuiting of the
lamp by the insertion of suitably arranged insulating material
Between the guide rods above mentioned a solenoid or sucking magnet of
suitable resistance and provided with rollers or guides is caused to roll or slide
vertically during the working of the lamp. The upper carbon is attached to this
solenoid and operated in the manner hereinafter described.
The solenoid or sucking magnet is formed with a suitable resistance as above
stated & placed as a shunt between the terminals of the lamp its rollers or guides
being so arranged as to admit of its readily rolling or sliding up and down between
the above mentioned guide rods. Through the hollow centre of the said solenoid
or sucking magnet pass two cores of soft iron placed end to end and between their
adjacent ends I place a spiral or other suitable spring tending to separate the said
cores from one another. One of the said cores, preferably the lower one, is hollow

page_text: to allow of the upper carbon holder attached to the upper soft iron core to pass
therethrough. This lower core operates and partially supports a catch or brake
which presses against the guide rods thereby supporting the solenoid or sucking
magnet. The said catch or brake may. be formed of two rods or bars each
supported by a short link attached to the bottom of the solenoid or sucking magnet
The inner end of each of the catch or brake rods or bars may be pivotted to the
lower core while their outer cnds may each carry a brake shoe or catch of suitablo
form to grip the guide rod upon which it travels, or the brake-shoo or catch may
be dispensed with & the outer ends of the rods themselves may be of suitable
form to grip the guide rods. The two catch or brake rods or bars should be of
such a length that they can never come into a straight line with each other when
pivotted to the lower core and placed between the guide rods but form an angle
When the said lower core is pressed outward & downward by the above mentioned
spring it tends to straighten the two rods or bars and force their outer ends
outward against the guide rods and so apply the catches or brakes The upper
core which carries the upper carbon holder as above stated may be supported by
the above mentioned spiral spring which when the lamp is in its normal condition
keeps a flange on the said core firmly pressed against the bottom of a screwed
tube or gland, screwed through a plate attached to the upper part of the solenoid
or sucking magnet. A portion of the upper core passes through the said tube or
gland which forms a guide for it.
The various parts of the lamp above described and in the modifications herein-
after described must be suitably insulated in a manner well understood in order to
ensure the passing of the current through the proper parts of the lamp and
prevent short circuiting.
The action of the lamp is as follows that is to say -The carbons being apart in
the first instance the current passes through the shunt solenoid or sucking magnet.
The upper soft iron core is immediately sucked downwards thereby lowering the
upper carbon while the lower core is sucked upwards drawing up the pivotted
inner ends of the two catch or brake rods or bars so releasing the pressure of the
brakes or catches upon the guide rods and allowing the solenoid or sucking magnet
and its attached parts to slide down until the carbons are in contact. Thereupon
the current being free to pass by way of the carbons is diverted from the solenoid
or sucking magnet and the elasticity of the above mentioned spring immediately
re-asserts itself. The lower core is pushed down and the brakes or catches applied
against the guide rods, whilst the upper core is raised and the arc between the
carbons struck. The current now continues to flow through the carbons and arc
until the resistance of the latter increases when more or less of the current will
pass through the solenoid or sucking magnet and the actions above described again
take place to a greater or less extent
In a modification of the lamp above described I may replace the two cores there
described by two iron cores semicircular in transverse section. One of these cores
which may be provided with a recess in its upper end I employ for operating a
catch or brake lever pivotted to the bottom part of the solenoid or sucking magnet.
The inner end of this brake lover may be slotted so as to embrace a pin fixed in
the lower part of the said core; whilst its outer end may be provided with a
curved surface eccentric to the axis upon which it is pivotted and so arranged as
to clasp or press against a portion of the guido rod upon which it acts when in
operation. I employ a spiral or other suitable spring or other equivalent device to
maintain the pressure on the catch or brake rod. One end of the said spring may
be inserted in the recess in the core above mentioned and its other end may be
placed in a similar recess in or otherwise attached to a screwed bolt passing
through a cap at the top of the solenoid. By turning the said screwed bolt the
pressure of the spring may be regulated at will. The upper carbon holder is
attached to the other semi-circular core the lower portion of which is formed of
brass or other non magnetic material whilst its upper portion is formed of soft iron
and is the part acted upon by the electric current when passing through the

page_text: solenoid or sucking magnet. The core carbon holder and carbon may be supported
or held up by a suitably arranged spiral or other spring or other equivalent device
Adjustable screws suitably arranged and passing through lugs on this second core
may be employed for regulating the distance through which it may move thus
limiting the length of arc. The operation of this modification will be readily
understood from what has been hereinbefore described.
In a further modification of the lamp above described I may employ only one
core the lower portion of which is formed of iron whilst its upper portion is formed
of brass or other non magnetic material. The lower portion of the said core may
be screw threaded and provided with a spiral spring and screwed collar the latter
being for the purpose of regulating the tension of the spring. At the upper end of
the core may be fixed a pin which enters a slot in one end of an adjustable pivotted
lever. The other end of this lever may also be slotted to embrace a pin or projec-
tion on the upper carbon holder which in this modification is bent away from its
central position below the solenoid or sucking magnet and passes up by the side of
the same in suitably arranged guides. The catch or brake which I employ in this
modification is composed of two rods insulated from each other and united at their
inner ends whilst at their outer ends they each carry a ring or fork which encircles
or embraces the guide rods. A pin projects from the central portion of the said
catch or brake rod and an adjustable spring connected to this pin and the top plate
of the solenoid always keeps the catch or brake rod and its two rings or forks
tilted or inclined to the guide rods and thus grips them with a greater or lesser
force. The said catch or brake may be carried by suitable bearings forming a
support attached to the upper plate of the solenoid or sucking magnet To the
upper brass portion of the core may be attached an adjustable screw or projection
so arranged that when the lower iron portion of the core is sucked within the
solenoid or sucking magnet by the action of a current circulating within it, the said
screw or projection comes in contact with the pin projecting from the catch or
brake rod, opposing the tension of the spring and releasing the catch or brake to a
greater or less extent and allowing the solenoid or sucking magnet and attached
parts to descend. The saine movement of the core also raises the inner end of the
pivotted lever and lowers the outer end to which the upper carbon holder is
attached and with it the upper carbon. When the resistance of the electric arc is
reduced and the current diverted from the solenoid or sucking magnet the spring
on the lower iron portion of the core withdraws the latter a short distance from out
the solenoid or sucking magnet raises the upper carbon holder and carbon and leaves
the pin on the catch or brake rod free to be acted upon by its spring which
immediately applies the brake.
In another modification I arrange the shunt solenoid or sucking magnet
horizontally and provide the same with two soft iron cores one for each half of the
samme At their outer ends the said cores may be provided with adjustable pro-
jecting points or knife edges or extremities of any suitable form to which brako
shoes may or may not be attached and which are caused to abut or press against
the vertical guide rods between which the said solenoid or sucking magnet slides
or rolls by means of a spring or other equivalent device placed between the inner
ends of the soft iron cores. Instead of the outer ends of the soft iron cores being
provided with points or knife edges or brake shoes I may provide them with
adjustable hinged rods bars or levers which may or may not have brake shoes or
clutches at their outer ends suitably arranged and operating in a manner substan-
tially the same as that herein before described with reference to the first form of
lamp. At the ends of the solenoid or sucking magnet I arrange masses or plates
of soft iron which become magnetised when a current traverses the said solenoid or
sucking magnet. To the solenoid or sucking magnet a frame or support is attached
in any convenient manner for supporting the upper carbon the said frame or
support being capable of a vertical motion. Attached to this frame and over the
masses or plates of iron at the ends of the solenoid or sucking magnet I place
masses of soft iron which when a current traverses the said solenoid or sucking

page_text: may
magnet. are drawn downward and with it the frame or support and upper carbon
rod. A spring arranged at the top of the solenoid or sucking magnet raises the
said frame or support and carbon rod and maintains the same in its raised position
when there is not sufficient current traversing the said solenoid or sucking magnet
to draw it down. Screws or other equivalent devices may be employed to regulate
the distance through which the frame or support may rise and fall. I may combine
portions of one form of lamp above described with portions of another.
also
combine with any of the forms of lamp above described a dash pot of any suitable
form arranged in any convenient manner or I may so arrange one or more of the
guides or rollers attached to the solenoid or sucking magnet that it or they may bo
caused to bear with a greater or less pressure against the guide rods and allow the
said solenoid or sucking magnet to descend at a suitable speed. For this purposo
the guides or rollers may be attached to a pivotted bar or frame a screw being
employed to adjust the pressure of the said slides or rollers upon the guide rod.
By thus causing a portion of the weight of the solenoid or sucking magnet to he
thrown on the vertical guide rods less work will be required to be done by the
current traversing the solenoid or sucking magnet in withdrawing the catch or
brake from the said guide rods.
The vertical guide rods may be of circular rectangular or other suitable cross
section and strengthened or braced laterally in any convenient manner

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said James Grieve Lorrain in the Great Seal Patent Office on the
11th July 1883.
JAMES GRIEVE LORRAIN, of 2 Victoria Mansions, in the City of Westminster,
Consulting Engineer "IMPROVEMENTS IN ELECTRIC ARC LAMPS"
My invention relates to improvements in that description of Electric Lamps
known as Arc Lamps, and comprises various novel features hereinafter described,
whereby an electric arc lamp of great simplicity and efficiency is obtained.
According to one mode of carrying out my said invention, I employ a solenoid
or sucking magnet of suitable resistance, and provide the same with rollers or
guides whereby it may move with more or less freedom between two guide-rods.
This solenoid or sucking magnet is placed as a shunt between the terminals of the
lamp. Through the hollow centre of the said solenoid or sucking magnet pass two
cores of soft iron placed end to end and having between their adjacent ends a
spiral spring or other suitable device tending to separate the the said cores from
one another. One of these cores, preferably the lower one, is hollow, to allow
the upper carbon holder attached to the upper soft iron core to pass therethrough.
This lower core operates, and partially supports, a catch or brake which presses
against the guide rods thereby supporting the solenoid or sucking magnet and its
attached parts. The said catch, or brake, may be formed of two rods or bars, each
supported by a short link attached to the bottom of the solenoid or sucking magnet.
The inner end of each of the catch or brake rods may be pivotted to the lower
core, while their outer ends may each carry a brake shoe or catch of suitable form
to grip the guide rod upon which it travels; or the brake shoe or catch may be
dispensed with, and the outer ends of the rods themselves may be of suitable form
to grip the guide rods. The two catch or brake rods should be of such length
that they can never come into a straight line with each other when pivotted to the
lower core and in position between the guide rods, but are so inclined to one
another as to form an obtuse angle. When the said lower core is pressed downward
by the above mentioned spring, it tends to place the two catch or brake rods in
line with each other, and force their outer ends against the guide rods, so applying
the catches or brakes. The upper core, which carries the upper carbon holder, as
above stated, may be supported by the above mentioned spring, which, when the
lamp is in its normal working condition, keeps a flange on the core firmly pressed
against the bottom of a screwed tube, or gland, screwed through a plate attached
to the upper part of the solenoid or sucking inagnet. A portion of the upper core
passes through the said tube or gland which forms a guide for it.
The construction of this form of my improved electric lamp is shown in figures I
and 2 of the accompanying drawing in which
Figure 1 is a side elevation, partly in section, thereof and
Figure 2 a section of the same on the line x x figuure 1.
A represents a solenoid or sucking magnet provided with rollers or guides a, a, a, a,
whereby the solenoid or sucking magnet may move vertically between the guide
rods B, B. These rollers or guides are preferably so arranged that they may be
caused to press with greater or less force upon the guide rods as hereinafter
described. The guide rods are connected at their lower portion by a plate B², as
shown, which carries a carbon holder 6 for supporting the lower carbon C. The
upper ends of the rods B, B', are similarly connected by the plate B³ provided with
a suspension ring D and carrying the terminals E, E, of the lamp. These terminals,
as also the rods B, B', are insulated from each other, as is well understood, to

page_text: prevent short circuiting of the lamp. F and G are two iron cores within the hollow
centre of the solenoid or sucking magnet, having between their adjacent ends the
spiral spring H which tends to separate the said cores from one another. The
lower core G is formed with a hole through its centre to allow of the upper carbon
bolder I, attached to the upper core, to pass therethrough; and to the said upper
carbon holder, which is of brass or other suitable non-magnetic material, the upper
carbon K is secured in any convenient manner. This lower core G operates, and
partially supports, the catch or brake composed of the two rods or bars L, L'. The
inner ends of these rods are pivotted to the core G, and further supported by the
short links M, M' attached to.the lower portion of the solenoid or sucking magnet
as shown. The outer ends of the rods L L' are shown provided with brake shoes
or catches N N¹ which partially embrace the guide rods B B¹, but the brake shoes
or catches may be dispensed with and the ends of the rods L L' made to abut
against or partly embrace the rods B B' if desired. It will be seen that the lengths
of the rods L L are such that they cannot come into a straight line when pivotted
to the lower core and in position between the guide rods, but form an obtuse angle.
O represents a tube or gland screwed through the plate at the top of the solenoid or
sucking magnet. A flange F' on the core F is pressed by the spring H against the
bottom of the said tube Ŏ, thus limiting the upward movement of the upper core,
and consequently the length of arc struck. By screwing the tube O in or out, the
length of arc may be varied to suit requirements. The guide rods B B' may be
strengthened or made more rigid by means of one or more rings or connecting
pieces P or other equivalent devices of metal or other suitable material. Care
must be taken to prevent short circuiting of any portion of the lamp, not
required to be so short circuited, by the insertion or use of suitably arranged
insulating material us is well understood.
The action of the lamp above described is as follows-The carbons being apart
in the first instance, the current passes through the shunt solenoid or sucking
magnet A. The upper soft iron core F is immediately sucked downwards thereby
lowering the upper carbon, while the lower core is sucked upwards, drawing up the
pivotted inner ends of the two rods L L', releasing the pressure of the brakes or
catches N N' upon the guide rods B B¹, and allowing the solenoid or sucking
magnet and its attached parts to slide down until the carbons are in contact.
Thereupon the current, being free to pass by way of the carbons, is nearly wholly
diverted from the solenoid or sucking magnet, and the elasticity of the spring H
immediately reasserts itself. The lower core G is pushed down, and the catches or
brakes N N' applied against the guide rods B B', whilst the upper core F is pushed
upwards, separating the carbons, and so striking the arc. As the carbons gradually
burn away the resistance of the arc increases when more of the current necessarily
passes through the solenoid or sucking magnet thereby influencing the length of arc
in the manner above described. This action is so continuous and rapidly
recurring that the lamp when in use burns with the utmost steadiness.
In a modification of the lamp, I may rej lace the two cores above described by
two iron cores semicircular in transverse section. I may also employ a brake or
catch formed of a pivotted lever whose outer end is provided with a curved surface
eccentric to the axis upon which the lever is pivotted, and so arranged as to clasp
or press against a portion of one of the guide rods upon which it acts when in
operation. This modification is shown in the figures 3, 4 and 5 of the accompanying
drawing in which
Figure 3 is an elevation, partly in section, of a portion of this modification,
Figure 4 a horizontal section on the line a figure 3 and
Figure 5 a side elevation of the solenoid or sucking magnet with its attached
parts.
In these figures, A represents the solenoid or sucking magnet provided with
rollers or guides a a (adjustable or otherwise), as in the form of lamp before!
described. F & G represent the two semi-circular soft iron cores which effect the
same operations as the cylindrical cores F & G shown in figure 1. One of these

page_text: cores G I employ for operating the catch or brake lever L pivotted to the lower
part of the solenoid or sucking magnet as shown. The inner end of this brake
lever may be slotted so as to embrace a pin c fixed in the lower part of the said
core G, whilst its outer end L' is provided with a curved surface eccentric to the
axis d upon which the lever is pivotted, and so arranged as to clasp or press
against the guide rod B with a varying and increasing pressure as the inner end of
the said lever is depressed by the said core G. To cause the pressure on the catch
or brake rod L, I employ a spring H of a spiral or other suitable form, or other
equivalent device. One end of this spring may be inserted in a recess in the top
of the said core G, as shown, whilst its other end may be placed in a similar recess
in, or otherwise attached to, a screwed bolt e passing through a cap f at the top of
the solenoid or sucking magnet. By turning the said screwed bolt the pressure of
the spring and consequently that of the brake lever L upon the guide rod B may
be regulated at will. A rod f' acting in conjunction with the plate f' at the bottom
of the solenoid or sucking magnet ensures the movement of the core G being
vertical. The semicircular soft iron core F has attached to its lower end the
upper carbon holder I, formed of brass or other non-magnetic material, which
supports the upper carbon K as before. The corc, carbon holder and carbon are
supported or held up by the spring g (or other equivalent device), attached to the
screwed bolt g' passing through the support or frame has shown. Adjustable
screws passing through the lugs l, on the upper carbon holder I may be
employed for regulating the distance through which the core F may move, thus
limiting the length of the arc. The operation of this modification will be readily
understood from what has been hereinbefore described.
In a further modification of my lamp, I may employ only one core, the lower
portion of which is formed of soft iron, whilst its upper portion is formed of brass
or other non magnetic material. This modification is shown in figures 6, 7 and 8
of the accompanying drawing, in which
Figure 6 is an elevation of a portion, partly in section.
Figuro 7 is a plan or top view of the solenoid or sucking magnet with some of
its attached parts and also the guide rods in section, and
Figure 8 is a side view partly in section of the solenoid or sucking magnet with
its attached parts.
In these figures A represents the solenoid or sucking magnet arranged in a shunt
between the terminals of the lamp, as before described, provided with the rollers or
guides a as shown. In this modification only one core is employed as above stated,
the lower portion F of which is formed of soft iron, whilst its upper portion F' is
formed of brass or other non-magnetic material. The lower portion F of the said
core may be screw-threaded as shown, and provided with a spring H', and screw
collar H, the latter being for the purpose of regulating the tension of the said
spring H. At the upper end of the core may be fixed a pin n which enters a slot
in one end of an ajustable pivotted lever N. The other end of this lever is also
slotted and embraces a pin or projection n' on the upper carbon holder I', which,
in this modification, is bent away from its central position below the solenoid or
sucking magnet, and passes up by the side of the same in suitably insulated guides
or holes formed in the brackets carrying the right hand rollers or guides a, a.
These rollers or guides a, a on the right hand side of the solenoid or sucking
inagnet are preferably formed of insulating material to prevent short circuiting of
the carbons. m² is an adjustable support for carrying the pivotted lever N.
The catch or brake, which I employ in this modification, is composed of two rods
L' L' insulated from each other, and united at their inner ends; whilst at their
outer ends they each carry a ring or fork L³ L' which encircles or embraces the
guide rods B B. A pin projects from the central portion of the combined rods
LL; and an adjustable spring connected to this pin and the top plate of the
solenoid or sucking magnet always keeps the catch or brake rods L' L' and their
rings L³ L* tilted or inclined to the guide rods B B', thus gripping them with a
greater or lesser force. The rods L' L' may be carried by suitably insulated

page_text: bearings M M forming a support attached to the upper plate of the solenoid or
sucking magnet. To the upper portion F' of the core is attached an adjustable
screw or projection so arranged that, when the core is sucked within the solenoid
or sucking magnet by the action of a current circulating through it, the said screw
or projection comes in contact with the pin l, and raises or inclines it.
The operation of this modification is as follows:-The carbons being apart in the
first instance, the current passes through the shunt solenoid or sucking magnet A,
whereby the lower soft iron portion F of the core is sucked upwards. This causes
the projection to come in contact with the pin projecting from the combined
catch or brake rods L' L' thus opposing the tension of the spring ', releasing the
pressure of the rings L³ L on the guide rods B B' to a greater or lesser extent, and
allowing the solenoid or sucking magnet with its attached parts to descend until
the carbons are in contact. The same movement of the core also raises the inner
end of the pivotted lever, and lowers the outer end to which the upper carbon
holder and carbon are attached. When the carbons are in contact the current is
almost wholly diverted from the solenoid or sucking magnet; whereupon the
spring H withdraws the core a short distance from out the same, raises the upper
carbon holder and carbon, thus striking the arc; and leaves the pin / more or less
free to be acted upon by its spring which immediately applies the_brake, and
holds the solenoid or sucking magnet with its attached parts fixed. The current
now continues to flow through the carbons and are until the resistance of the
latter increases, when more or less of the current will pass through the solenoid
or sucking magnet, and the actions continue to recur as previously described.
In a further modification I arrange the shunt solenoid or sucking magnet
horizontally, and provide the same with two soft iron cores having a spring
between their inner ends as in the form of lamp first herein before described.
modification is illustrated in figures 9 and 10 in which
This
Figure 9 is an elevation partly in section of a portion of this modification and
Figure 10 a side or end elevation of the solenoid or sucking magnet with its
attached parts.
In these figures A represents the solenoid or sucking magnet as before provided
with two soft iron cores F & G having a spring H placed between their inner
ends. These cores are provided at their outer ends with projecting points or knife
edges L L¹, or extremities of any other suitable form (to which brake shoes may or
may not be attached), and which are caused to abut or press against the vertical
guide rods B B', between which the said solenoid or sucking magnet slides or rolls,
by means of the spring H or other equivalent devices placed between the inner ends
of the cores F & G. The projecting points or knife edges are preferably made
adjustable, as for instance by screwing them into the ends of the cores as shown,
in order that the pressure which they exert (by reason of the spring H) against
the guide rods B B₁ may be varied to suit requirements. The said projecting points
should also be insulated as shown to prevent short-circuiting and sparking.
Instead of the outer ends of the soft iron cores being provided with points or
knife edges or brake shoes they may be provided with adjustable hinged rods bars
or levers, which may or may not have brake shoes or clutches at their outer ends,
and arranged and operating in a manner substantially the same as that herein before
described with reference to figures 1 and 2. At the ends of the solenoid or
sucking magnet I arrange masses or plates of soft iron M which become_magnetised
when a current passes through the said solenoid or sucking magnet. To the said
solenoid or sucking magnet a frame or support N is attached as shown, for
supporting the upper carbon, the said frame being capable of a vertical motion, by
means of a pin band slot b' (figure 9). Attached to this frame and over the
masses or plates M of iron I place other masses N' N' which, when a current
traverses the solenoid or sucking magnet, are drawn downward together with the
frame or support N and upper carbon rod K by the then strongly magnetised
masses M. A spring O, arranged at the top of the solenoid or sucking magnet,
raises the said framo N and carbon rod, and maintains the same in their raised

page_text: position when there is not sufficient current traversing the said solenoid or sucking
magnet to draw it down. Screws P P or other equivalent devices in conjunction
with the screw P' may be employed to regulate the distance through which the
frame or support may rise and fall, and therefore the length of arc. Small pins or
projections c attached to the solenoid or sucking magnet and projecting into the
grooves c¹ on the cores F and G prevent these latter from rotating round their axes.
The operation of this modification will be readily understood from what has been
hereinbefore described.
The guides or rollers attached to the solenoid or sucking magnet are preferably
so adjustably arranged that they may be caused to bear with a greater or less
pressure against the guide rods, and allow the solenoid or sucking magnet to
descend at a suitable rate. For this purpose the guides or rollers may be attached
to a pivotted frame or bar, screws being employed to adjust the pressure of the said
slides or rollers upon the guide rods. This arrangement of adjustable guides is
shown in figures 9 and 10 in which the guides a replace the rollers shown in the
other figures. These guides a consist of bars a¹ provided with a bearing surface a³
and hinged or pivotted to a plate a³ as shown in figure 10. By means of a small
set screw a*, working against the face of the end masses M of iron, the pressure of
the guides a upon the guide rods B B' may be varied at pleasure. It will be
obvious that the rollers shown in the other figures may be similarly mounted or
replaced by the adjustable guides just described. By thus causing a greater or
lesser amount of pressure to be exerted against the guide rods by the rollers or
guides less work will be required to be done by the current traversing the solenoid
or sucking magnet in withdrawing the catches or brakes from the said guide rods.
It will be obvious that, instead of using the lamp vertically, it may be used
horizontally; the action of gravity being replaced in this case by suitably
arranged springs or weights. I may also combine portions of one form of lamp
with portions of one or more of the other forms of lamp herein described. It will
be obvious also that, instead of employing a solenoid or sucking magnet arranged
as a shunt between the terminals of the lamp, I may arrange it in the main circuit :
or it may be provided with two series of coils of wire, one of which is in the main
circuit, and the other in a shunt circuit; the working parts of the lamp being in
these cases suitably modified to meet the altered conditions. Thus when the
solenoid or sucking magnet is arranged in the main circuit the brake or catch and
arc-striking devices require to be reversed, as will be readily understood from the
foregoing description.
The vertical guide rods may be of circular, rectangular or other suitable form in
transverse section, and strengthened or braced laterally, in any convenient manner.
Having now fully described my invention & the manner in which it may be
carried into effect, I would state in conclusion that what I consider to be new and
original, and therefore claim is :—
First In an electric arc lamp the employment of a solenoid or sucking magnet,
arranged in a shunt or derived circuit between the terminals of the lamp, and
sliding or rolling between guide rods, & having a core or cores which serve to
regulate the feed of one of the carbons or electrodes, separate the carbons or
electrodes, and strike the arc, substantially as herein before described.
Second In an electric arc lamp the combination of a solenoid or sucking magnet
sliding or rolling between guide rods with a catch or brake composed of a pivotted
rod or rods actuated by a core of the said solenoid or sucking magnet, substantially
as hereinbefore described.
Third-In an electric arc lamp the combination of a shunt solenoid or sucking
magnet and its contained core or cores with guido rods between which it slides or
rolls, substantially as herein before described.
Fourth In an electric arc lainp the use of a solenoid or sucking magnet having
two contained cores which are sucked in opposite directions when a current passes
through the said solenoid or sucking magnet, substantially as bereinbefore
described with reference to figures 1, 3, 4 & 9.

page_text: Fifth In an electric arc lamp a shunt solenoid or sucking magnet having its
axis at right angles to guide rods, between which it slides or rolls, & having cores
which are pressed outwards against the said guide rods, for the purposes herein-
before set forth.
Sixth-In an electric arc lamp the employment of adjustable guides to bear upon
guide rods, substantially as herein before described with reference to figures 9 and
10, and for the purposes specified.
Seventh-The general constructions, arrangements and combinations of parts
constituting electric arc lamps, substantially as herein before described, with reference
respectively to figures 1 and 2, figures 3, 4 and 5, figures 6, 7 and 8, and figures 9
and 10.
In witness whereof I tho said James Grieve Lorrain have hereunto set my
hand and seal this eleventh day of July in the year of our Lord One thousand
eight hundred and eighty three.