IMPROVEMENTS IN AND RELATING TO ELECTRIC LAMPS AND APPARATUS TO BE USED IN THE MANUFACTURE OF THE SAME
Year: 1883

page_text: LETTERS PATENT to William Robert Lake of the firm of Haseltine, Lake
& Co Patent Agents Southampton Buildings London for an Invention of
"IMPROVEMENTS IN AND RELATING TO ELECTRIC LAMPS AND APPARATUS TO
BE USED IN THE MANUFACTURE OF THE SAME communicated to him from
abroad by Carl Ludwig Rudolph Ernest Mondes of the Haœno Holland
"
PROVISIONAL SPECIFICATION left by the said William Robert Lake at
the Oflice of the Commissioners of Patents on the 4th June 1883.
WILLIAM ROBERT LAKE, of the firm of Haseltine, Lake & Co, Patent
Agents, Southampton Buildings, London, "IMPROVEMENTS IN AND RELATING TO
ELECTRIC LAMPS AND APPARATUS TO BE USED IN THE MANUFACTURE OF THE
"
SAME [A communication to him from abroad by Carl Ludwig Rudolph Ernest
Menges of the Hague, Holland]
§1. This invention relates to electric lamps or lighting apparatus and comprises
the employment of two carbon pencils which are kept in contact under constant
pressure and put in communication with a source of electricity. The said invention
also relates to apparatus to be used in the manufacture of the said lamps.
The light obtained by means of this invention differs from the "arc light" in so far
that in the are light the carbons are standing still whilst burning; it is also different
to the incandescont light as this light arises from the continued incandescence of a
solid body. The resistance to the passage of the electric current from one carbon
to the other is generally the cause of a serious inconvenience which however
disappears entirely according to this invention. The heat and the flickering of the
ordinary lights is concentrated in my improved apparatus the result being an
advantageous use of electric energy. The light is also very regular, whilst the
suitable pressure of the carbon points which is obtained by this invention is much
more preferable for the stendiness of the said light than the interval which is
allowed in other lights between the two carbon points. This process of electric
lighting may be carried on in a vacuum or in the air or in any other gas without
departing from the nature of the said invention. Preference will be made to the
use of various kind of carbons such as carbons with metallic covering, carbona
mixed with other substances, such as graphite, and other descriptions of carbons.

page_text: The following description will bear first upon the construction of the lamp for
open air burning, secondly upon the construction of the said lamp for burning
in vacuo, thirdly upon the use of the various carbons.
The accompanying drawings will serve, as an example, to further illustrate this
invention. Heretofore the carbons used to generate the electric light have been
made very long in comparison with their thickness, so that the electric current in
passing through these carbons met with greater resistance than was necessary.
The two carbons c d, and c e were held by two clasps a and b which were put in.
communication with the two poles of a source of electricity so as to bring the
current close to the point of contact. As the clasps pressed rather strongly upon
the carbons (so as to prevent too much resistance to the passage of the electric
current) the resistance caused by the friction of the said carbons in the clasps when
these were moved forward to replace the portion of the carbons consumed gave rise
to considerable irregularity in the light. When the two clasps were tight, it was
impossible to keep the carbons in contact under a constant pressure even if the
said carbons were pushed forward by a constant force and this is the reason why,
according to this invention, one of the two clasps (and if necessary both) is rendered
movable and pressed by a constant force in the direction of the other clasp (the
force is derived from a spiral spring shown in Figure 1 but omitted in the other
Figures so as to simplify the drawing) so that the carbons meet at c and remain in
contact under constant pressure during their consumption. The carbons are
pushed through the holders by means of either a continuous or an intermittent
motion. This is effected in such a manner that the movable clasp b retains its free
motion within certain limits by means of a suitable mechanical contrivance.
Z, B shew in Figure 1 a chain (ribbon wire, wire rope, band or the like) which is
used for the propulsion of the carbons. The movable clasp b is connected with a
lever. The chain p, l, k, e is passed over a roller h fixed at the base of the lamp
in such a manner that the point where the chain runs over corresponds with the
axis of the lever k, l. In this arrangement the force which pulls at the chain has
no influence on the pressure at the point of contact c, the only pressure being
effected upon the axis l. Further arrangements in connection with the above
described lamp will be hereinafter described.
In the lamp as shewn in Figure 1 the axis of the lever is horizontal and
the carbons are placed at an angle to one another in order to economize space.
The force is that of a weight n which moves like a piston (with packing) in a
cylinder . The lower part of the cylinder is put in communication by means of a
pipe t with a slide box or casing in the same manner as in a steam engine. The
whole apparatus is filled with a liquid. A slide valve permits the partial or
complete closing of the pipe above mentioned. The motion of the slide valve is
caused by means of an extension m of the lever kl and in such a manner that as
the carbons are being consumed the valve slides and opens a gradually increasing
portion of the aperture of the pipe in consequence whereof the liquid flows from
below the piston n which accordingly descends the result being a forward motion
of the carbons. The liquid flows out of the slide casing through a side pipe fand
back again into the cylinder. Should the carbons be pushed forward with greater
speed than is necessitated by their consumption the sliding valve closes the
aperture more tightly, so that the apparatus works automatically. When the
carbon points are required to be changed, the piston n must be promptly raised
this being effected by means of the cock at t which puts the lower part of the
cylinder in communication with the upper part thereof. The above described lamp
may also be constructed so that the axis shall be vertical or so that the mechanical
contrivance which causes the carbons to be propelled may be fixed below the
cylinder which necessitates merely a small alteration in the working of the chain
This lamp may also be made with two movable carbon holders, the clasp a in
that case being provided with a lever arrangement similar to that for the movable
clasp b.
The two levers should be connected so that the motion of the one will
cause a similar motion of the other, this connection may be effected by means of

page_text: different contrivances. The above arrangement may be useful for optical purposes
as the light remains in that case strictly at the same spot.
The carbon points in
the lamp shewn in Figure 1 are similarly arranged, the consequence being that they
are consumed in equal proportions (the direction of the electric current has no
influence). It has been proved that when the two carbons are placed in a
vertical position their consumption takes place equally when the dispersion of heat
is sufficient
The lamp as shewn in Figure 1 may also be constructed with a vertical
arrangement of the carbon points, in this case one of the chains may be dispensed
with, whilst the piston, as shewn in Figure 2, is provided with a rod n and a
cross-head d, g which acts directly upon one of the carbons. The chain p, 1, k, e
is not directly connected with the piston but is connected by means of a rod o, g
to the cross head d, g. According to this arrangement the chain is not brought in
contact with the liquid in the cylinder. This latter arrangement is also applicable
to the apparatus shewn in Figure 1. In the apparatus shewn in Figure 2 the
working by means of the slide valve and other pieces is exactly similar to
that shewn in Figure 1 and for that reason these pieces have been omitted from
this Figure of the drawing
The construction of the apparatus shewn in Figure 3 is similar to that shewn in
Figure 2 as regards the cylinder, the piston, the piston rod and other parts, the
only difference being the omission of the slide valve and slide box. The regulation
of the motion of the carbons is effected by means of clicks which actuate the
rack o g. Two arms are fastened to the click one of which carries a weight
which is set in motion when the click r is raised; this motion may however be
prevented by means of the other arm r, which abuts upon the lever arm k, m.
When the carbon points are shortened by reason of their consumption the leverkl
is raised (by means of a spring, a counterpoise or the like) and the arm Im falls
In consequence thereof the arm r, is set free and the click ŕ unlocked The piston
in the cylinder fi descends whilst the liquid flows through the pipe t into a
cylinder q. In the cylinder q moves a piston which is not completely closed.
Owing to the pressure of the liquid this piston and its rod are raised and the
click becomes locked again. As the carbons have been advanced a little, the
arm l, m is raised and the click is secured by means of the arm 1. The flow of
the liquid ceasing, the piston which as above mentioned is not completely closed
descends in the cylinder q into its former position
Instead of the said clicks, other contrivances may be used such as screws, clasps
or friction rollers.
A Lamp provided with clockwork is shewn in Figure 4. In this case the motive
force is a weight which directly pushes the upper carbon forward and at the same
time sets the clock-work in motion by means of the rack o g. The stopping or
starting of the clock-work is effected at the proper times by means of a lever
arın . r, which according as the carbons are being consumed is either held fast or
set free. The other parts of the construction are shewn clearly in the Figure.
§ 3 In the above described lamps a chain is used for the propulsion of the carbons,
through the movable clasps.
Any other contrivance, as stated in § 1, may be devised in such a manner as not
to interfere with the motion of the clasps. For instance in Figure 5 is shown a
driving gear-wheel o which is set in motion by means of a rack g, o, (which is also
a motion rod) and which sets another rack p, k, in motion by means of the toothed
wheel p, the latter rack p, k, propels the carbon through the movable clasps, the
axis of rotation of the lever which carries the clasp 6 passes through the centre
of the wheel p (the axis is here obviously meant as a tine, the real axis being
either on one side or broken so as to allow room for the wheel p). The
propulsion of the carbon is independent of the position of the clasp b and the
pressure at c is not interfered with. As regards the other parts, this lamp may be
constructed exactly similar to the others hereinbefore described. In Figure 5 is
shown a gear-wheel for imparting motion to the fly. wheel q, this wheel being fixed

page_text: on the shaft upon which the gear-wheel is mounted. the operation is the same as
in the above described lamps. Arrangements that will only allow of a short
motion may be also devised, great space not being required for the movable clasp.
An instance of this is given in the arrangement shown in Figure 6, the movable
lever carries a toothed wheel h which is acted upon by the wheel p and this propels
the carbon through the clasp b by means of the rack p, k,. The teeth of the
wheel are in gear with those of the wheel h₁ which receives its motion from the
rack g, o, by means of a pinion O. The axis is the tangent common to the half
of the width of both wheels h, and h₁. The motion is not interfered with if the
wheel h is slightly lowered.
$* It is not absolutely necessary that the movable clasp should be connected
with a lever, as the motion inay be obtained in other manners: In Figure 7 the
clasp b is fastened to a rod k, l which is arranged to slide in grooves between the
two rods f,i,. the carbons are propelled by means of a screw provided with a nut
and a handle and working in the same manner as the screw of a lathe. The said
screw is rotated by means of a toothed wheel p, which is in gear with a wheel o.
This wheel o is niade so that there shall be no hindrance to its being put in gear
with the wheel p, when the clasp b is pushed forward (by reason of the
consumption of the carbons). The wheel o receives motion from a motor which
propels also the other carbon by means of a screw or other contrivance. The
stoppage and setting in motion of the motor is effected from the motion of an
arm l, m, in the same manner as for the above described lamps. In order to be
able to screw on the nut e easily when new carbon points are being put in this nut
is composed of either one half or two halves which are easily parted so that the
screw may be turned with facility.
In the lamp shown in Figure 8 the carbons receive an approximately straight
motion and are connected with two levers lc, l, and k, l, the axes of which pass
through , and ₁, respectively. Motion is imparted to the carbons by means of a
chain as hereinbefore described. The wheels are fixed upon the rod g, o, so as to
form part thereof. The pinion is set in motion by the rack t, t, this rack being
firmly fixed upon the frame of the lamp. A fly-wheel with an arm q or any other
regulating arrangement is set in motion by means of a worm and a worm-wheel,
the stoppage of this fly-wheel takes place when the arm 9 strikes a plate r, r,
which is movable around a vertical axis in the same manner as an ordinary door.
The fly-wheel is both set in motion and stopped by the turning of the plate r, r,
which is independent of the position of the wheels, the other parts of the lamp are
similar to those of the above described lamps with this exception that the plate
r, r, is put in motion by the lever k, l, m, by means of a bent lover and a rod.
This lamp may also be provided with clock-work whereby the rack is set in motion
and the pinion n is placed opposite the worm wheel; the plate r, r, then takes the
form of a lever arm.
.
8 Several lamps may be mounted upon the same pedestal. In this case one set
of carbons only is employed at a time, the carbon points of the other not being
supplied with the current. A contact device is held by means of a system of
clicks, As soon as the first carbons are consumed, the rod o, g is released by the
clicks and the second set of carbons is put in operation, at the same time the
click arrangement interrupts the communication of the first set with the source
of electricity. The contact device above mentioned is well known in connection
with various apparatus.
As
In order to economize space, several lamps may be built into one another in
such a manner that some of the parts of one of these lamps serve for all the others.
An instance of a double lamp is shown in Figure 9, this lamp being constructed in
the same manner as that shown in Figure 8 with merely a few additions.
shown in Figure 9, b, k,, is a double carbon-holder connected with a lever k, l.
Each carbon has its own chain (which chains are superposed in the Figure), one
chain being connected with the other chain P₁.
The movement of the chain is somewhat different to that of the chain herein-

page_text: before described, the roller h is not fixed upon the base of the lamp but is connected
with the lever k, l, and in order to prevent the traction of the chain interfering
with the motion of the lever, the roller is so placed that the point at which the
chain runs off the roller is in line with the axis of the lever k, l,. The operation
of this lamp is the same as that of the preceding ones.
With reference to the automatic motion of the second pair of carbon points, an
arrangement of clicks is, as above described, sometimes made use of in similar
circumstances, whereby the rod o, g, is set free at the requisite time. In the
present case, however, another arrangement is used. The arm q₁ is engaged by the
lever k, l, by means of a pawl. This pawl is of such size that when the lever k, l,
commences to move in consequence of the consumption of the carbons, the rod is
not set free. When, however, the rod o, g, has descended to its lowest position, the
carbons cease to be propelled, the lever k, l, is raised higher than before by reason
of the consumption of the carbons and the rod is consequently set free. The
second pair of carbons then come in contact whilst the first pair are thrown out
of contact and the lever k, l, returns to its normal position.
Clock work, as described in § 4 and shown in Figure 8 may be used and fixed
on the lamp, in which case the rods o, g, and o₁, g₁, are made into racks which
are put in gear with a pinion. One set of clockwork is sufficient, the two pinions
are mounted loosely on the same shaft and are worked by means of clicks and
ratchet-wheels.
§ This mechanical contrivance may, under the circumstances, be arranged partly
or entirely in the same manner as above described, for instance in the same manner
as the arrangement shown in Figures 4 and 7. In the same manner a lamp like
that shown in Figure 4 may be constructed with the arrangement for the motion
of the carbon-holders and the clockwork shown either in Figure 8 or in Figure 9.
Each lamp, which is operated by means of a weight, will work equally well in an
inverted position providing the weight is attached to a chain and this chain placed
around a roller. If it is desired to use the clockwork instead of a weight as
shown in Figure 8, the said clockwork must obviously be disconnected from the
rod o, g, and will then produce an opposite motion to that which it previously
produced. To effect this arrangement a chain must be attached at o passed over
the roller at and again attached at the base of the clockwork. The clockwork
is therefore disconnected from the rod o, g, but caused to move instead along the
rack t, t.
The clock work may be used as a fixture, the rack is then dispensed with and
the pinion n is passed through a roller provided with points or projections upon
which is laid the chain fastened at o, the end of the chain which is not fastened
at o is arranged to carry a weight, the other parts of the lamp remain the same as
above described; the weight may easily be replaced by a spring, in which case the
lamp may be used in any position.-The above described arrangements may be
slightly altered, for instance in the lamp shown in Figure 1 the chain instead of
having a weight attached to it may be connected to a drum which is set in motion
by means of clockwork. If the lamp is placed so that the axis lies above the
carbons, the lamp is then capable of giving a light from above.
Each of the above described lamps may be used in a different position, the
relative position of the component parts of the said lamps not being altered,
although their absolute position is changed in the same manner as it has been
possible to arrange, for the fixing of various parts of a kinematic chain, different
pinions, as has been done by means of rollers in the process above described. Thus
the lamp shown in Figure 8 may be easily inverted, the side frame becoming the
top of the said lamp. If d, g, is fixed and the frame is rendered movable in a
vertical direction as in Figure 10, the lamp will work in the same manner as
described in § 4 and shown in Figure 8. All the above described lamps may be
inverted in the same manner.
§7 The electric current is brought to the carbons through the clasps a and b and
there should be as little resistance as possible to the passage of the electricity to

page_text: these carbons.
Carbons covered with a metallic coating are particularly advan-
tageous for this purpose. The resistance is also greatly reduced by increasing the
points of contact. Various arrangements for carbon clasps are shown in Figures 11,
12, 13 and 14. The clasps consist of a fixed part a and a movable part a₁,
connected together, between which parts the carbon c, d, is grasped by means of a
spring. The movable part (shown separately in Figure 13) is provided with a sort
of metallic brush similar to the brush for the commutators in dynamo-electric
machines. In Figure 14 is shown a brush affixed to the part a the carbons being
carried along by means of a small roller. The contact obtained by means of these
brushes is such as to offer little resistance to the passage of electric currents and to
cause a gentle and uniform friction.
The various mechanical arrangements of the lamps have for their object to
determine the stoppage and setting in motion of a powerful motor in such a
manner that the movable clasp is not interfered with. Should only a small force
be required consequently upon the use of carbons sufficiently smooth, such as
carbons with a metallic covering as above described, the arrangement becomes
much simpler without there being any fear of an injurious amount of friction, In
accordance with the above description and as shewn in Figure 15, the lever-
arm 7 m acts upon a spring clasp r, whereby the descending of the rod o, g, and the
propulsion of the carbons are regulated, Instead of the above described spring
clasp the same piece may be made into a click and the rod o, g, into a rack.
The clasp may be made to act upon the carbon c, d, instead of the rod o g, as
shewn in Figure 16. The spring clasp thus serves as a carbon clasp whereas the
movable part of this clasp is connected with the lever k, l by means of an arm ?
and a rod. In order to obtain a smooth motion, the rod o, g, in Figure 15, and the
rod d in Figure 16, may be connected with a piston capable of moving in a
cylinder filled either with liquid or with air.
§ 8 Under certain circumstances one of the holders need not be movable and the
two carbons may be pressed one against the other through the clasps by a constant
force. On account of the difference between the co-efficient of friction when the
clasps are made fast or movable and to have anything approaching a constant
pressure at the contact points of the two carbons, a very small amount of friction
must be allowed in the clasps
As this however is not generally the case, the clasps must be made movable,
except when smooth carbons rubbed in graphite, or carbons prepared as herein before
described, are employed in which case fixed clasps will answer the purpose,
Such
an arrangement is shewn as an example in Figure 17. One of the carbons is
pressed down by the weight of the rod g, o and at the same time the other carbon
is raised by means of a chain p, k, e. Another arrangement similar to that just
described is shewn in Figure 18, in this case the clasps are provided with two
contact-rollers. As a substitute for the chain any other arrangement for the motion
of the rod o, g, as in Figure 17, in a contrary direction to that of the said chain,
will also answer the purpose, such for instance as two racks and a toothed wheel.
These simple arrangements are especially useful in the case of relieving lamps
which are only intended to burn whilst new carbons are being put in the main
lamp. As this operation takes only a short length of time to perform, the
arrangement for the propulsion of the carbons may be dispensed with and short
carbons may be used and kept in contact under a constant pressure; in that case
the clasps may be altogether dispensed with. The contrivance for the propulsion of
the lower carbon may also be dispensed with as a change in the position of the light
would not be inconvenient; the lamp thus simplified is shewn in Figure 19.
Another arrangement with inclined carbons is shewn in Figure 20. The carbon-
holder e, Z revolves around an axis and is pushed towards the other carbon by
means of a spiral spring (or a weight). In order not to be obliged to replace the
carbons too often, longer carbons may be used which must be slowly propelled.
Should it be desirable that this operation should be performed in a simpler manner,
the chain arrangement, as shewn in Figure 1, may be used. The cylinder operating

page_text: by means of a liquid, the sliding box, and other parts may be dispensed with when
it is required to propel the carbons by hand. The relieving lamps might also
be easily made to work automatically. In that case the contact piece of an
electro-magnet is put in communication with the movable carbon for instance with
the lever le Figure 20. The electro-magnet is connected with the conductors
which convey the electric current to the main lamp. So long as this lamp burns,
the contact piece of the electro-magnet remains in communication with it, the
carbons of the relieving lamp are kept apart and the current does not pass into the
relieving lamp although the two carbons of the latter are connected to the con-
ductors. As soon as the current is diverted from the main lamp the contact piece
of the electro-magnet is withdrawn and the carbons of the relieving lamp come
into contact.
§ 9 Such simple arrangement as shewn in Figure 15 may be used also with a
powerful motor when the force acting upon the holder is not obtained by means of
the lever k, or when such a force is not requisite; in that case the electric
current may be used by either the aid of an electro-magnet which would cause the
escapement of the rod as before mentioned by means of a contact piece or by using
the electric current as a motor. Electro-magnets or motors may be connected
either with an additional conductor branching off from the main conductor
(Figure 21) or with the main conductor itself (Figure 22). The connection of the
conductor with the lamp is effected by means of the attachment screws L and L₁,
and that of the carbon clasp a with the current is effected through the base of the
lamp by means of the attachment screw L₁, whereas the movable clasp shewn in
Figure 21 is connected to the circuit through a pliable metal band by means of
the attachment screw L. When by reason of the consumption of the carbons the
movable clasp b is raised, the arm k, m, comes in contact with the spring vw
whereby the connection of the additional conductor is severed from the electro-
magnet or the motor M. The carbon will be propelled until the connection
between v and m is broken when the spring v w strikes the screw u. In Figure 22
is shewn at m an insulated knob which is fixed upon the arm 1 m. As long as the
spring v, w is in contact with the screw u the electric current passes on without
going through the electro-magnet or motor M. When however by reason of the
motion of the arm 7m the connection between v and u is broken, the current flows
through M. Either of the clasps a and b (or both) may be insulated from the base
of the lamp. The above description renders the path of the electric current clearly
comprehensible. The mechanical contrivance above described for effecting the
motion of the holders or the escapement of the rack may be applicable to the
lamps above described, as shewn for instance in Figure 7 where an electric motor
is used.
§ 10 The alteration in the form of the carbons caused by their consumption may
be utilized to set in motion at the proper time the device for effecting the escape-
ment of the rod independently of the movable clasp As shewn in Figure 23 a
lever arm u is pressed by means of a weight or a spring against the carbon c d.
When the carbon assumes a pointed shape, the lever u moves and sets the escape-
ment arrangement in motion. In order to be able to easily place the arm u in its
proper position the motion is imparted by a lever arm w. The arm wis loose
upon the axis ₁ and the motion of the lever u is imparted to the lever w by
means of an arm (provided with a set-screw v) which is fixed on the said
lever u
The operation of the arrangement shewn in Figure 24 is similar to that of the
lamps above described as will be understood upon reference to the said Figure.
The arrangement shewn in Figure 25 is another form of that shewn in Figure 24
the only difference being the introduction of fixed carbon clasps. When either
one or both clasps in either of these lamps is arranged in the manner aforesaid
and the stoppage arrangement is dispensed with, the carbon c, d will be propelled
until the motion produced by means of the projections 7, r is stopped. As the
carbons are being consumed, they are also propelled, so that the length of that

page_text: If the two
portion of the carbon which is outside the clasp remains constant.
clasps are provided with this arrangement each carbon may be supplied with an
independent motor such as a weight or spring, hydraulic power or the like.
§ 11. The constant pressure requisite for the carbons of all the above described
lamps may be obtained from a weight instead of a spring or from hydraulic power
or in any other suitable manner.
In order to obtain a slow and regular motion of the carbons various regulators
may be devised (such for instance as that shown in Figure 5). With a view to
avoid using too many wheels, the regulator may be set in motion by means of a
flow of liquid obtained from a reservoir which is kept filled with the same liquid;
this reservoir being provided with a lid in order to prevent the escape of the said
liquid when the apparatus is being moved from the vertical to the horizontal
position and vice versa, this arrangement will serve equally well when the axis of
the regulator is horizontal. When the lamps are working regularly, the carbons
are propelled a little at a time, so that the regulator q or any other arrangement is
in motion only for a short period of time and consequently is soon stopped again.
It is necessary to fix a small fly-wheel upon the shaft of the regulator as the
inertia of this wheel will prevent a too rapid starting of the machinery and will
enable the stoppage of the same to be effected before too great a speed has been
attained.
In order to prevent the pressure obtained by means of weights from varying in
intensity at the contact points by reason of the different lengths of the carbons a
chain is attached at e (Figure 8) and is passed over two rollers at k and l, and
fastened to the frame p of the clockwork. The weight belonging to this chain is
so arranged as to have the same length as the weight of the chain e k and the same
size as the carbon. It is therefore obvious, when either long or short carbons are
used, the lever k, is equally loaded. This arrangement is applicable to all the
above described lamps. If any obstacle prevented the propulsion of the carbons or
if these carbons were consumed it may happen that the lever k,l being raised to its
highest position as for instance in Figure 8, the carbons would cease to be in
contact. Under those circumstances all the lights in the lamps which are situated
in the same electric circuit would be extinguished. In order to avoid such an
occurrence each lamp is provided with an arrangement whereby the electric current
would in that case be suddenly interrupted. The movable carbon-holder with the
clasp is put in communication by means of a soft metal band with the attachment
screw L, this screw being insulated from the frame of the lamps; the attachment
screw L is connected with the said frame. The electrical conductors are connected
with both the attachment screws L and L. The carbon-holder is provided with a
shoulder which through the rising of the piece k abuts against the pin u fixed on
the frame of the lamp and establishes communication between L and L₁. It is
obvious that if the clasp b and the attachment screw L are connected with the
frame of the lamp, the pin u and the attachment screw L₁ must be insulated from
the said frame. This arrangement is applicable to all the above described lamps.
§12 The above described electric lighting apparatus answers equally well when
used in all kinds of gaseous atmospheres and accordingly any of the lamps above
described may be enclosed in any envelope which has been exhausted of air or
which has been filled with any gas. The object of such an arrangement is to
prevent the consumption of the carbons. However it must be considered satisfactory
to be able only to reduce such consumption and accordingly the lamp is entirely
enclosed in a glass globe or casing which prevents the introduction of air. This
lamp may be provided in the same manner as an air pump with a bell and a tray.
In fact a part of the lamp itself as for instance the base in Figure 5 or the upper
part of the frame in Figure 8 may be arranged so as to serve as a tray for the said
bell. As the free oxygen soon combines with the carbons, the consumption of the
said carbons under these circumstances will soon be diminished and in that case
the propulsion of the carbons may be effected by hand so that the motor and its
accessories may be dispensed with. The propulsion may be effected from outside

page_text: by means of a rod passing through a stuffing box. This simplification has a further
advantage that the apparatus can be reduced in size and the free oxygen present
will be smaller in quantity. The consumption of the carbons will thus be so far
reduced that the contrivance for the propulsion of the said carbons through the
clasps may be dispensed with and the lamp consequently assumes the form of a
relieving lamp as shewn in Figure 8, This lamp may be entirely enclosed in a
glass case as before mentioned and the conductors may be made of cast platinum
wires. Figure 26 illustrates this arrangement. In order to be able to place the
lamp within the case the latter is made in two distinct parts which are shewn joined
at xy. A glass tube is soldered at the lower part of the case which supports the base
of the lamp, One of the cast platinum wires L is connected by means of the spiral
spring a with the lever le which is insulated from the other parts of the apparatus; the
other wire L, is in connection with the base f of the lamp After the connection
is thus established the glass case y is fused at x, y, and in order to be able to
accomplish this operation, a glass tube is fixed either at the top or bottom of the
case, the closing of this tube being effected after the lamp has commenced to burn
in order to prevent the said lamp bursting when lighted in consequence of the
dilatation of the air. When the lever is balanced by a counterpoise as shewn, the
lamp will burn in any position. All the herein before described lamps can thus be
enclosed in a glass globe or case such for instance as the lamp described in § 9.
Other gas may be used as well as air such as hydrogen or nitrogen. This latter
gas may be obtained by placing a stick of sodium or potassium, or of any other
metal which is easily oxidized, in the lamp when full of air or in a glass flask put
in communication with the lamp. By reason of the heat developed by the burning
of the lamp, the metal rapidly combines with the oxygen present and the oxide
produced absorbs, after cooling, the moisture and carbonic acid which may be
present. There is a great disadvantage attending such lamps, viz;-the disinte-
gration of the carbon, the dust which results forming a cloud over the lighting
portion of the carbon. In order to remedy this defect in the case of vertical
carbons, a jacket a₁ a₁ (a cross section which is shewn in Figure 27) is placed
around the upper clasp a and serves as a chimney to draw the dust upward. This
jacket may be lengthened at the top by means of a tube, another jacket may also
be placed around the lower clasp. The light appears to greater advantage when a
glass bell narrowed in the middle is employed together with carbon points arranged
as in Figure 28. For lamps such as that shewn in Figure 19 the carbons are
covered in by means of a glass bell. The lamp shewn in Figure 26 may be used
in an inverted position as in Figure 29 the chimney as shewn at a, b, fitting in a
box b₁ where the dust settles.
The
$13 The lamp described in the above paragraph may be so arranged as to
permit it to be exhausted of air. For this purpose and in order to be able to
exhaust it as completely as practicable thus preventing, to a great extent, the
consumption of the carbons the lamp must be hermetically enclosed in a glass globe
or case as shewn in Figure 26. In this case the chimney arrangement is useless.
Whilst the air is being exhausted the current is allowed to pass through the lamp
so that the heat will rid the carbon points of any air they may contain.
current is allowed to increase gradually in intensity until the light has the requisite
power, the glass case being closed whilst the current passes through the lamp.
The movable lever L, c has scarcely any motion, yet it is absolutely necessary to
make sure that the pressure derived from the construction of the apparatus should
not only be constant but remain so when changes occur by reason of differences of
temperature or the carbons slightly disintegrating or volatilizing.
The axis of rotation may be provided with two flat springs in the same manner
as the axis of a pendulum. If the movable portion of the apparatus is constructed
as light as possible the counterpoise of the lever le Figure 26, may be dispensed
with Figure 30 shews an arrangement of this kind. In order to keep the carbon
points in contact and to prevent their separation, half round or flat carbons with

page_text: their widest surfaces facing each other may be used instead of round carbons as in
the lamps shewn in Figures 26 and 29
When the carbons are flat and very thin their elasticity is very great and when
such carbons are used in the lamp shewn in Figure 30, for instance, this elasticity
supplies the necessary pressure required at the contact point. The spring 1, e
Figure 30, may consequently be dispensed with, relying upon the said elasticity of
the carbon to obtain the necessary pressure as shewn in Figure 31; this arrange-
ment with the omission of the spring will be readily understood
14 When a number of lamps are employed in the same circuit, it is a matter
of importance that the resistance offered by each lamp should be alike. As the
proportion of the resistance of the carbon in a cold and in a hot state is about
constant for all carbons of the same description it is sufficient to give all the lamps
the same resistance when the carbons are cold. This may be easily effected by
altering the length of the carbons d, c and ec previous to closing the glass
casing. When the length of the carbon is altered, the resistance is also
altered and the result is a change in the lighting power of the lamp.
The alteration of the carbons may be effected when required with the
construction of the complete lamp as shown in Figure 32. The mechanical
contrivance whereby the carbons are propelled is exactly similar to the one used
in the lamp shewn in Figure 1. Instead of the chain being connected with a
piston it is in this case attached to the nut o of a screw. The spindle of the
screw carries a weight n. When the apparatus is turned so that the spindle p
is horizontal, the said spindle is not moved but the nut o is set in motion.
According to this arrangement the carbons may be propelled as desired. If the
carbons are required to be pulled back an endless chain is used as described in
§ 11 or each carbon is connected to a spring which acts upon the chain as shewn
in Figure 32 at k, e and g d. If the weight in Figure 32 is placed upon an iron
bar n, n Figure 33 fixed in a transverse position on the screw p, this screw p may
be set in motion by means of an electro-magnet N, S. The arrangement for the
revolution of the electro-magnet by means of the knob A and the passage of the
current across two insulated rings with contact springs is clearly illustrated in the
Figure.
This arrangement may be made so that the current will pass through the lamp
and not through the electro-magnet and by means of an ordinary commutator the
current may be passed when required through the electro-magnet.
The arrangement as shewn in Figures 32 and 33 may also be used in lamps
containing air, to propel the carbons when they are getting short
§ 15 The exhausting of the air may be performed with any ordinary exhaust
pump. The following arrangement is comprised in the present invention the
principal parts being shewn in Figure 34. A cylinder a, a, a, a is closed air-tight
by means of a lid on the outside of which is fixed a cock. In this cylinder
is a receiver which is movable up and down and which is provided at b, b with a
piece of packing. The impermeability may be obtained in any ordinary manner
as the exhaustion of the air need only be partial as will be hereinafter explained.
From the lid of the cylinder a hangs a glass belle provided at f with a cock or
valve, the vessel which is to be freed from air is connected with the tube g which
is in communication with the bell e and the receiver b, c. The return of the air
is prevented at g by means of a cock or valve supplied with mercury. The
vessel b, c is also filled with mercury. The operation of this pump is obvious.
When the receiver b, c for instance, is pushed down by means of a crank and
sliding rod, there is a space free from air in the cylinder a in consequence of
which the air rushes through the tube g into the bell e.
When the receiver b, c
is raised the cock or valve g is closed and the air is pressed through the cock or
valve into the cylinder a and is expelled through the cock d. It must be
remarked that when the cylinder a still contains a little air the bell e on the
contrary is as free from it as possible, as the difference of pressure indicates, the
level of the mercury at e being higher than it is in the receiver bc. The

page_text: advantages of this arrangement consist in the work being performed automatically
and the pumping being rapid. Only small quantities of mercury are required,
and this mercury does not come in contact with caoutchouc or with the outside
air; the cock or valve is only slightly loaded as a very little mercury suffices
to close it so that altogether the apparatus is both simple and not easily
breakable
§ 16 The devices shewn in Figures 35, 36 and 37 serve for the fastening of the
lamps and their connection with the conducting wires. In a cylindrical jacket a, a
Figure 35 is placed a piece b, b which is movable up and down in the jacket a, a
and is pressed upon a prominent edge of the inside thereof by means of a spiral
spring inside the same. The attachment screws L and L₁ are connected with the
hooks of two spiral springs. When the piece b, b is raised in the jacket the
platinum wires of the lamp are easily hooked and when the piece is lowered the
lamp becomes tightly fixed as shewn in the figure. A tongue c serves for the
fastening of the lamp to a lighting arm. The attachment screws L and L, and
the spiral springs 8 and 8₁ are insulated from one another, they may be made of
metal, wood, ebonite, or other suitable material. In Figure 36 is shewn a
jacket a, a made of compressed metal, and below in the same figure is shewn the
tongue c fixed at the lower part of the piece b, b. Two attachment screws may be
further used in this case. As shewn below the figure one of the spiral springs is
connected with a metal jacket by means of a screw-threaded stem, whereas the
other is connected through the middle of the tongue with a knob e. By screwing
the part d into the part d₁ the connection with the lamp is established. In order
to prevent the two spiral springs 8 and 8, of the apparatus as shewn in Figures 35
and 36 coming accidentally in contact, the ends of these springs are attached to a
piece of wood or ebonite at a proper distance from one another, so that the hooks
are slightly separated.
According to the arrangement shewn in Figure 37 a metal jacket is arranged
below the lamp. The bottom of this jacket is placed upon a disc of wood, ebonite
or the like which is provided with a metal knob in the centre. The jacket a and
the knob e are connected with the conducting wires of the lamp. The jacket a, a
is provided with two pins these two pins being fixed to another jacket by means
of a bayonet joint.
The connection with the conductors is effected by means of the metal jacket b
and the spiral spring 8. The spiral spring which produces the pressure in the
lamp also serves to secure the said lamp, and the side split for the Bayonet joint
is slightly bent out as shewn in the Figure.
$17. When a lamp is required to be fixed upon a revolving lighting arm or
bracket as in Figure 38 the current passes through the movable parts at A and B
by means of a device shewn in Figure 39. This device consists of two cylindrical
parts made of wood, ebonite or the like a cylindrical concavity being cut out of
one of these cylinders, and another in the shape of a ring being similarly cut out
of the other cylinder; in these concavities the conducting wires are inserted
twisted into the shape of a spiral.
According to this arrangement the arm can be moved horizontally in either
direction, but according to the arrangement shewn in Figure 40 the arm can only
move in one direction.
The connection with the conductors takes place by means of conical rings placed
one inside the other whereby the oxidation of the contact surfaces or their contact
with other bodies is avoided.
§18 In order to be able to make or break the circuit the arrangement shewn in
Figure 4 is employed. Two small metal plates a₁ a₁ are placed upon the base of
a cone a made of wood, ebonite or the like. This cone lies in a conical opening
made in the piece b, b in which are placed two small metal plates, which cover
exactly the plates α a. The piece b, b is made of insulating material and the
metal plates which are fixed thereon are put in connection with the conductors of
the current by means of the attachment screws c, c. When the cone is so placed

page_text: that the two small plates a, a, cover exactly the plates fixed in the piece b. b, the
current is interrupted, but if the cone is turned round through an angle of 90°,
the plates a, a, establish communication between c and c. In order that the cone
shall only occupy either of the two above mentioned positions and at the same
time obtain a proper pressure between a and b, a spiral spring is used which presses
against the pin d.
According to the form of the spiral spring it will be readily understood that by
a partial rotation the cone is forced back to its original position. A continued
rotation as far as the pin d causes the cone to abut against the pin e the spiral
spring slides over the pin d so that this pin is immediately placed in an exactly
opposite direction. It is obvious that if another pin like the pine is used the
movement of the cone is limited to the quarter of a revolution. The object of the
form of the contact surfaces has been described in the last paragraph and shewn in
Figure 40, that is to say, when the current has been interrupted for some time
there is no liability to oxidation whilst the contact surfaces cover each other
exactly. Instead of using conical contact surfaces flat ones will also answer the
purpose in all cases.
It is to be understood that in the various arrangements described in §§ 16, 17, 18
both conducting wires are insulated. If only one of the wires is required to be
insulated, matters are simplified and one half of Figure 39 for instance may be
omitted, whereas the lighting arm in Figure 38 may be used for the return
current.
§ 19. To prevent the lamp and the conductors being destroyed by an accidental
surplus of current an apparatus as shewn in Figure 42 is placed at various parts of
the conductors this apparatus works on the same principle as the thin wire of the
lightning conductors used in telegraphy.
For the present purpose it is desirable to offer as little resistance in the conductors
as possible, accordingly the interruption should not take place between two short
intervals so that the appearance of a voltaic arc should be avoided. In the ordinary
construction of lamps, one of the above conditions excludes the other, but as shewn
in Figure 42 both objects can be accomplished.
The conductors from L to L₁ are formed with a metal spring, with a piece of
ordinary metal a, a piece of fusible metal b and another piece c of ordinary metal.
When the piece b is melted, the piece a arrives at the position marked in dotted
lines on the drawing in consequence of the endeavour of the spring to come back
to its original position as well as by the weight of the piece itself. The piece b
may be very small and a further interruption is obtained. This piece b may be a
piece of wire a plate made of fusible metal or metallic composition, it should be
wider at its extremities A and B so as to obtain a better contact as it is attached
by its wide ends.
§ 20. As regards the choice of the metal which is to be used for the various parts
of the apparatus, the usual rules will have to be followed. It should be remarked
however that clean nickel has been found to answer the object very well for the
manufacture of carbon clasps not only for the vacuum lamp but also and more
especially for lamps intended to burn in the open air, as this metal resists
oxidation by reason of its high melting point.
The insulation which is required for some parts of the apparatus may also be
obtained in the usual manner, but for the lamps described in §§ 12, 13, and 14 it
will be necessary to use glass, stone, mica or the like.
The glass casing of the lamps may be made of opal glass; or corrugated surfaces
may be employed for lamps burning in a vacuum. The two above mentioned
sorts of glass answer, as a rule, very favorably to avoid much loss of the electric
light as the said light is being diffused through these glasses. A grooved glass
would also answer the purpose providing the grooves on one side of the glass are in
a contrary condition to the grooves on the other side.
§ 21 All kinds of carbons may be used. As only a small portion of the carbon
is included in the electric circuit in the case of lamps with carbon clasps, any bad

page_text: conducting or inferior carbon will answer the ordinary purpose. It may be useful,
under certain circumstances to use carbons offering great resistance, namely when
the light is to be put up at a great distance from the machine. The heated carbon
paste which serves to inanufacture the carbons may be mixed with badly con-
ducting and difficultly fusing substances, for instance earths like aluminiferous
ores and others or metalloids and their combinations such as nitrates of Boron,
nitrates of silicium and the like
Often a judicious selection of the carbonaceous matter such as some graphites
which is to be used for the manufacture of carbons may enable (without any
foreign admixture) badly conducting and difficultly fusing carbons to be obtained.
It is also desirable to have good conductors, for example with the clasps described
in $7, which offer a good conducting surface. In this case the carbons are covered
with a thin galvanic coating of light fusible metal such as silver or zinc which will
not interfere with their use. A thick metallic covering, may also answer the purpose
in so far as to mainly conduct the current close up to the contact points of the two
carbons. Metals which are easily fusible are also of use in this case, these carbons
being particularly useful for such constructions as those described in § 8 when no
carbon clasps are used; these carbons are then fixed in a metal sheath. By using
the above described carbons the arrangements described as "relieving lamps" may
be constructed to burn for a much longer time than they would otherwise do.
The same object which can be obtained by a good conducting carbon sheath
namely the use of longer carbons in lamps without carbon clasps may also be
attained when a bad conducting core is placed inside a good conducting carbon.
In this case the good conducting carbon sheath acts towards the bad conducting
core in the same manner as the herein before mentioned metallic covering acts
towards the ordinary carbon. In this arrangement a current with a higher
tension is required which is a great advantage under the circumstances. The
carbon core is arranged in a similar manner to that described for the metallic
carbons. A mixture of carbon with non-conducting substances or simply bad
conducting substances may be used as a bad conducting core as has been already
mentioned at the commencement of this paragraph respecting bad conducting
carbons. The carbon core may be usefully covered with a thin layer of metal.
The carbons in one lamp may also be different to one another one being provided
with a clasp and the other one with a carbon core. As far as concerns the
manufacture of carbon cores a good conducting hollow carbou may first be
manufactured and a bad conducting core may be subsequently inserted in the said
hollow carbon, both being usefully separated by a layer of syrup, tar or the like,
the whole being rendered incandescent; this last operation may be repeated several
times. A good conducting sheath may be manufactured by rendering a bad
conducting carbon incandescent in an atmosphere of carbureted hydrogen gas.
The carbon may be manufactured and filled in with the core at the same time by
means of the carbon press arrangement shewn in Figure 43 or Figure 44. In the
space A is placed the good conducting material whilst the bad conducting material
is introduced into the space B a good conducting carbon tube being subsequently
passed out of the cylindrical aperture a, a and filled at the same time with the bad
conducting material. A cotton or other thread may be placed in the space B
Figure 44 mixed with substances which after having been rendered incandescent*
produce a core which is a more or less good conductor. When a lamp with
inclined carbons is used the bad conducting material may be applied on the outer
side of the carbon.
§ 22 With carbons such as those used for the lamps described in §§ 12, 13
and 14 whether used in vacuo or in the open air it is obviously unnecessary that
these carbons should be difficult of consumption. Carbons which are of good
quality for open air burning may be quite useless for burning in vacuo, and vice
versa.
Generally speaking it may be said that carbons for consumption in vacuo should
be more homogeneous than for any other consumption. It is preferable in this case

page_text: that they should be porous whereas when they are used for open air consumption
the contrary holds good, as the air penetrates a porous carbon and consequently
causes it to be consumed more rapidly. For open air consumption, carbons made
of powdered carbon mixed with some binding material answers the purpose well,
whereas for consumption in vacuo carbons made without special binding material
are preferable, for instance, carbons obtained from the carbonization of vegetable
matter such as wood, paper or the like. The carbons may be cut out of wood,
parchment-paper or the like and carbonized into a powder or put in a retort filled
with carbureted hydrogen and rendered incandescent. A paste may also be made
of woody fibres or paper fibres and water. By the addition of sulphuric acid,
chloride of zinc or ammoniated peroxide of copper, the fibres can be converted into
vegetable parchment by well known methods, subsequently washed and then
moulded in the usual manner into pieces of the size and shape required. Other
substances may be used for the bad conducting material, or their carbonization
may be effected as described in the above paragraph. With bad conducting
substances, Boron, Silicium or black diamond may be used, as the price of the
carbons is not so much an object considering the small quantity which is required
for use but not consumed. Hollow carbons and carbons covered with a metallic
layer may also be converted as above described. The carbons made with the
carbon attached to the sides of gas retorts may be very useful but by reason of
their tendency to become dissociated, they are seldom used. In the distillation
of coal-tar through incandescent tubes clean material obtained in the same manner
might be manufactured into very good carbons. The carbon which in this distilla-
tion is found attached to the sides of the tubes is too expensive for consumption in
the open air, and of no use for consumption in vacuo; proper sized carbons are
easily cut out of such material. Good carbons may also be manufactured with
material obtained from subjecting metal wires or plates to galvanic incandescence
in an atmosphere of carbureted bydrogen.
The carbons made in the usual manner from baked powdered carbon may be
used for consumption in vacuo if the carbon or the binding material offers sufficient
resistance. However this is not worthy of much consideration as it generally
occurs that carbons so manufactured are not alike, and although the same binding
material may be used in the same proportion whether syrup, tar, gum or other
material is employed, the resulting carbons are sometimes entirely different. Carbons
prepared in this manner are made to last longer by being rendered incandescent in
an atmosphere of carbureted hydrogen.
Soot mixed with syrup or tar yields a very good carbon. When small carbons
covered over with a metallic layer are used in the lamps described in §§ 12, 13
and 14 the ends of these carbons which are grasped by the clasps may be rendered
good conductors by means of a galvanic covering. The carbon may also be covered
by a thin piece of metal plate a portion of the said plate being made to protrude
and both the plate and the carbon being subsequently subjected to the action of
galvanism. The protruding portion is then clasped in tightly so that there is no
liability to injury of the carbons. The carbons may also be connected with the
carbon-holders by means of a paste made of graphite, gum or other suitable
binding material. The carbons may be directly connected by means of this paste
(which may be also subjected to galvanism) to the platinum wires of the lamp
shewn in Figure 31, omitting in that case the arrangement of screws shewn in
the Figure.
When heated whilst the air is being exhausted the binding material
is decomposed, the liquid substances are expelled and there remains a binding
material consisting of carbon only.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said William Robert Lake in the Great Seal Patent Office on the
4th December 1883.
WILLIAM ROBERT LAKE, of the firm of Haseltine, Lake, & Co, Patent Agents,
Southampton Buildings, London, "IMPROVEMENTS IN AND RELATING TO ELECTRIC
LAMPS AND APPARATUS TO BE USED IN THE MANUFACTURE OF THE SAME"-
A communication to me from abroad by Carl Ludwig Rudolph Ernest Menges,
of the Hague, Holland,
This invention relates to electric lamps in which the carbon points are held
continually in contact under a uniform or constant pressure, and to apparatus to
be used in the manufacture of the said lamps.
For convenience of description I will divide the specification into a series of
articles as follows, that is to say :-
Article 1. The method employed according to the present invention for generating
electric light consists in the application of two carbon points which remain in
contact with each other under a uniform pressure and are traversed by the electric
current. It does not therefore refer to the electric arc light, as the carbon points
always remain in contact, nor to the so-called incandescent light whereby one
continuous substance is made incandescent. While contact resistance generally
constitutes a disadvantage in this method of generating electric light, the action of
the contact resistance from one carbon point to the other is highly favorable.
The production of heat, and hence also of light, is thereby concentrated thus
resulting in a thorough utilization of the electric energy; moreover, the light
produced is very uniform, because by a proper construction it is much easier to
keep the appropriate pressure constant than to maintain a certain distance between
the carbon points.
The said invention, moreover, comprises the use of the improved method for
generating light in a vacuum or in air or other gases. Also the employment of
different kinds of carbons, such as metallized carbon, or carbon combined with
other substances, such as plumbago.
I will hereinafter describe, first, the construction of lamps having their carbon
points in air, second, lamps with their carbon points in a vacuum, and then the
carbons. The forms of construction described and shewn in the accompanying
drawings are to be considered as examples of the application of this invention, the
different principal parts of the lamps described being designated by similar
letters.
In order to maintain the electric light for a considerable length of time, the .
carbons used require to be rather long as compared with their thickness. If,
therefore, the electric current is caused to pass through the whole length of the
carbons, a great deal of useless resistance is the result. Both carbons c, d and c, e
are, therefore, held by means of clamps or clutches a and b, the latter being connected
with the poles of an electric source, thus conveying the electric current close to the
points of contact of the carbons. The pressure of the clamps against the carbons
being necessarily very great (in order to avoid injurious electric resistance), the
extent of the variations of the frictional resistance in pushing the carbons through
the clamps to compensate for their consumption will generally be found very
considerable. If both clamps or clutches were made stationary, this would render
it impossible to obtain a constant pressure of the carbons at their point of contact,
even if the carbons were advanced by means of some constant power. One of the
clamps or in some cases each of the same is therefore made movable and, by
means of some constant power (in Figure 1 by the action of a spiral spring, the
1

page_text: same being omitted in the succeeding Figures of the drawings for the sake of
simplicity), is pressed forward and in the direction of the other clamp or clutch,
so as to cause the carbons to remain in contact with each other at c under a
constant pressure, even while they are consuming. The carbons are advanced
through the clamp either continuously or at intervals. In the case of the movable
clamp, this is effected by means of a mechanical device which will permit the clamp b
to retain a free movement (within certain limits), thus in Figure 1 a chain, cord,
wire, wire-rope, band or the like is employed for moving the carbons forward.
The clamp or clutch bis fastened to à lever device k, l and a chain pl ke passes
over a roller h applied to the frame of the lamp in such a manner that the point
where the chain engages with the said roller is situated in the axis of rotation
of the lever k, l. Thus the power pulling at the chain has no influence on the
pressure at c, since a pressure is produced at the axis / only. Other arrangements
will be hereinafter described when I give a description of the lamps in detail.
Article 2. In the lamp shown in Figure 1, the axis of the lever l l is horizontal
and the carbons, in order to economize space, are arranged at an angle to each other.
The moving power in this instance is obtained from a weight n which moves in a
cylinder fi in the manner of a piston, that is to say, with packing. The lower
part of the cylinder is connected by means of a pipe with a valve-chest similar to
those used in steam-engines, the entire device being filled with some liquid. By
means of a slider the inlet aperture of the said pipe may be more or less closed.
Movement is imparted to the slide by an extension lm of the lever in such a
manner that the opening of the pipe becomes larger as the points of the carbons
are consumed; in consequence thereof the liquid under n is allowed to escape, the
piston is lowered and the carbon points are advanced. The liquid leaves the
valve-chest through a side pipe f by which it returns into the cylinder. If the
carbon points are advanced faster than they are consumed, the slide rin turn
reduces the opening, the apparatus thus working entirely automatically. In order
to allow of the piston n being more readily raised when fresh carbons are to be
inserted, the cock t is opened, whereby a communication is established between the
upper and lower parts of the cylinder.
The lamp herein before described may also be constructed in such a manner as to
have the axis arranged vertically, or so as to arrange the mechanism with the
carbons on the lower part of the cylinder, this requiring but a small alteration in
the arrangement of the chain. The lamp may also be constructed with two
movable carbon-holders, it being only necessary in this instance to connect the
clamp or clutch a with a lever device similar to kl. In this instance both levers
would have to be so connected that the movement of the one would produce an
equal movement of the other in an opposite direction, many different imechanical
devices adapted for this purpose being sufficiently well known. Such construction
may be found useful for optical purposes, as the light will then always remain at
exactly the same place.
The position of both carbon-points in the lamp Figure 1 being similar, they are
both consumed in the same proportion (the direction of the electric current being
without influence on this result). Experience has shown, however, that even when
the carbons are arranged vertically one above the other, both will be consumed to
the same extent when suitable provision is made for removing the heat. The lamp
Figure 1 may, therefore, be constructed with vertical position of the carbons. In
this case the chain may be dispensed with by providing the piston, as in Figure 2,
with a piston-rod n and cross-head dg for advancing one of the carbons by direct
action. Furthermore the chain ple is not directly connected with the piston,
but by means of a rod og it is connected with the said cross-head dg, thus
preventing any communication of the chain with the liquid in the cylinder. This
arrangement may likewise be employed in the construction shown in Figure 1. In
all other respects the action of the lamp Figure 2, as to its slide and other parts,
is similar to that shown in Figure 1, for which reason all these parts are here
omitted.

page_text: The construction illustrated in Figure 3 is similar to that in Figure 2, with the
cylinder, piston and piston-rod, but without the slide and valve-chest. The feed of
the carbons is here regulated by means of a ratchet-device acting on the rod og,
the latter being constructed in the form of a rack. The pawl r is provided with
two extensions one of which carries a weight having a tendency to disengage the
pawl but prevented from so doing by ineans of the other extension 7¹, which
bears against the lever arin 1 m. The carbon points being consumed, the lever
arm is raised (by means of a spring, counterweight, or other device) and the
lever arm m, is depressed. The extension of the pawl drops in consequence of
the pawl becomes disengaged. The piston in the cylinder fi now descends, as
the liquid is permitted to escape through a pipe at into a cylinder q. This
cylinder q has a piston which is not perfectly fitted in the same.
The said piston,
together with its piston-rod, is raised by the pressure of the liquid, thus re-engaging
the pawl with the rack. The carbons, meanwhile, having been somewhat
advanced, the lever arm l m lias been raised and the pawl is again held in position
by its extension r¹. The liquid now being at rest again, the piston in the
cylinder q which, as above mentioned, is not fitted perfectly, resumes its original
position. Instead of the ratchet device above described a friction or clutch device
may be used.
Figure 4 shews a lamp in combination with clock-work, the motive power, in
this instance, being derived from a weight which pushes forward the upper carbon,
while, at the same time, by means of the rack og it imparts motion to the said
clock-work. The temporary setting free or releasing and arresting of the clock-
work is caused by the movement of the lever-arm r, which arrests and sets
free or releases the arm q. as the carbons are consuined. In all other respects the
construction will be clear from the drawings.
Article 3. In the lamps as herein before described a chain or cord is used for
advancing or pushing forward the carbon in the movable clamp or clutch. But, as
mentioned in article 1, any other contrivance not preventing the said clamp from
moving may be applied for the same purpose. For instance, in Figure 5, motion is
imparted to a pinion o through the rack go (which, at the same time, serves as a
driving rod); the said pinion o, by means of a universal joint and a spur-wheel p,
imparting motion to the rack plc, the latter pushing forward the carbon in the
movable clamp b. The axis of rotation of the lever carrying the clamp b cuts the
centre of the universal joint. (As is well understood the axis of rotation, in this
instance, only means the line of the said axis, as the actual axis either lies to one
side of the cross-bar of the universal joint, or is broken in the middle to make room
for the said joint). Thus the advancing of the carbon takes place independently
of the position of the clamp b without influencing thereby the pressure at c. In
all other respects the lamp may be constructed like the other lamps above described.
In the drawings a worm is used for imparting motion to the fly q, the shaft
carrying the pinion o having a worm-wheel applied to it. The effect is the same
as that of the lamps above described.
Such devices as admit of only a small movement may also be applied, because
the movable clamp requires but little play. Figure 6 is an example to illustrate
this. The movable lever carries a spur-wheel h₁ with a follower p which, by
means of the rack p k, pushes forward the carbou in the clamp b. The teeth of
the wheel h¹ are in gear with the spur-wheel h, the latter being rotated by means
of the rack go in gear with the pinion o.
The axis of rotation of the lever b
forms, at the same, the mutual tangent on half the breadth of the two wheels h
and h. The transmission of the motion is, therefore, not interfered with by a
little play of the lever b, because this produces only a slight inclination of h¹.
Article 4. It is not absolutely necessary to apply the movable clamp to a lever,
since it may, if desired, be guided positively in a different manner. As for
instance, in Figure 7, the clamp b is fixed to a rod k, which, by means of a
suitable guiding-frame, is capable of being moved on two guide-rods fi. In this
instance, the feed of the carbons is produced by means of a screw-threaded
D

page_text: mandril ph provided with a nut and arm e e', the motion being similar to that of
the slide-rest of a lathe. Rotary motion is imparted to the said screw-threaded
mandril by means of the spur-wheel p mounted thereon, the said wheel gearing
with the teeth of a pinion o. This pinion is made a little broader than the
wheel P in order to prevent the said wheels from coming out of gear with each
other when the movable clamp b descends slightly in consequence of the carbons
being consumed. The pinion o is rotated by means of any convenient motor, the
latter, at the same time, by means of a screw-threaded mandril or otherwise, being
adapted to push forward the other carbon. The motive power is interrupted and
caused to act by the movement of an arm l m in a manner similar to that in the
other lamps. In order to admit of readily shifting the nut e when fresh carbons
are to be inserted, the said nut is preferably constructed in halves so that it may
be readily disconnected from the screw-threaded mandril.
In Figure 8, the carbon-holder bk is guided in an approximately rectilinear
direction, the said holder being applied to two levers and k', the axes of
rotation of which are at l and . The movement of the carbon, in this instance, is
produced by means of a chain in a similar manner to that hereinbefore set forth.
The wheel-work is rigidly connected with the rod go so that it will descend
therewith. The pinion n is rotated by descending on the rack tt, the said rack
being rigidly secured to the casing or frame of the lamp. Furthermore, a fly or
other regulating device having a catch-arm q is rotated by means of a worm and
worm-wheel. Now, the rotary motion is interrupted by the arm q striking against
a plate which, like a door, allows of being turned on a vertical axis. The,
stopping and setting free or releasing is produced by turning the plate rr, whether
the wheel-work or gearing occupies a high or a low position. For the rest, the
operation is similar to that of the devices herein before described, motion being
imparted to the plate rr from the lever k l m by means of a joint-lever and rod.
The lamp last described may also be combined with stationary clock-work o g,
being then constructed as a rack and the pinion n being arranged on the opposite
side of the worm-wheel. Moreover r is simply reduced again to the form of a
lever-arm.
Article 5. Two or more lamps may be constructed on one frame. In this instance,
only one lamp is in operation at a time, the carbons of the other lamp then
receiving no current, a contact making device being kept disconnected by means
of a ratchet device. As soon as the carbons are very nearly consumed, the ratchet
device is set free by the movement of the rod og and the other lamp is put in
action, while simultaneously the same device breaks the circuit passing through
the first lamp. Contact making devices of this kind are well known.
With a view to economize space, two or more lamps may also be constructed one
within the other, so that some parts are common to both of them. A double or
duplex lamp of this kind is illustrated in Figure 9 of the drawings. In the instance
shown, the construction illustrated in Figure 8 has been made use of, but any other
arrangement may also be modified in the same manner. In Figure 9 a duplex
carbon-holder bis fastened to the lever kl. Each carbon has its own chain (the
one being covered by the other in the drawings) one of which is connected with p
and the other one with p'. The manner in which the chains are guided is here
somewhat changed in the drawings, that is to say, the roller h, in this instance, is
not applied to the frame of the lamp, but is applied to the lever instead.
Now, in order to prevent the force of traction from interfering with the mobility
of the lever, the roller h must be so arranged that the point where the chain leaves
or runs off from the roller, will lie in the axis of rotation of the lever kl. The
operation of the lamp is similar to that shewn in Figure 8. For automatically
switching in the other pair of carbons, some ratchet device may be used, the said
ratchet device being set free at the proper moment by means of the rod og as
above described. But in the present instance another device is shown, that is to
say, the arm q is stopped by means of a pawl applied to the lever kl. This pawl
is made sufficiently large to provide against an untimely setting free or releasing

page_text: of the arm q', which otherwise might be caused by the movement of the lever k
during the consumption of the carbons. But when the rod o has reached its
lowest position, the pushing forward of the carbons ceasès. The carbons being
consumed, the lever will be raised higher than before, and the arm q' will be
set free. The other pair of carbons will now be brought into contact while, at the
same time, the first pair will be put out of action, the lever returning to its
normal position.
In a similar manner to that above described in article 4, with reference to
Figure 8, stationary clockwork may also be applied in the present instance, it being
then necessary to construct the rods o g and o¹ gl as racks, each rack to gear with
a pinion. Thus but one set of clock-work is required, as both pinions are mounted
loosely upon the same shaft, revolving the latter only by means of a ratchet and
pawl.
Article 6. In some cases it may be preferable to arrange the mechanism entirely or
partly near the top or upper part of the lamp. Examples of such devices have
been shown already in Figures 4 and 7. Moreover a lamp of the pattern shewn in
Figure 4 may be constructed with the device having the movable carbon-holder
and clock-work shewn in Figure 8 or Figure 9. Each lamp actuated by means of
a weight may also be used in a reversed position, if the weight is suspended by a
chain running over a roller. It is clear that if, as in Figure S, the weight of the
clock-work be used as the power, the former cannot be applied to the rod og since
its movement will have to be in an opposite direction. To provide for this, a chain
need only be connected with o, the said chain passing over a roller at and being
fastened to the frame of the clock-work. The latter, as will be understood, must
then not be connected with og but must remain movable along the rack t t.
The clock-work may be made stationary, likewise. The rack t t will then be
dispensed with and a roller having points be substituted for the pinion n, the said
chain, which is connected with o, being laid over the said pointed roller. The
other end of the chain which is not connected with o must then carry an impelling
weight. For the rest, the action will remain entirely the same as before.
The impelling weight may also easily be replaced by a spring, the lamp being
then fit for use in any position. The arrangement may then be slightly changed, as,
for instance, the chains in the lamp Figure 1, instead of being connected with an
impelling weight n, may be connected with a drum having motion imparted to it
by means of spring clock-work. Now, if the lamp be reversed or turned upside
down so that the axis will lie above the carbons, a convenient lamp for giving
light from above will be obtained.
Each lamp may be used in another position, likewise, the relative movement of
the parts remaining unchanged, but the absolute movement being changed, in a
similar manner to that described by Reuleaux, according to which, by fixing
various links of a kinematic chain, various motions may be produced. Thus the
lamp Figure 8 may simply be reversed, the casing or frame to be at the top.
Now, if & g be fixed and the frame made movable vertically, Figure 10, the lamp
will operate in exactly the same manner as has been described in article 4 with
reference to Figure 8. In a similar manner all the other constructions may bo
changed.
Article 7. The electric current is conducted to the carbons through the clamps a
and b, consequently in transmitting electricity to the carbons there must be the
least possible resistance. Metallizing the carbons will give a very good result
in this respect. Also by multiplying the number of points of contact, the
resistance of transmission is considerably reduced. Different constructions of
carbon-clamps answering the said purpose, are illustrated in Figures 11, 12,
13 and 14. The clamp consists of a fixed part a and a movable part a¹, the
carbon c d being clamped within the said two parts by means of a spring.
The movable part (shewn separately in Figure 13) is provided with a kind
of metallic brush, like the commutator brushes used in dynamo-electrić
machines. In Figure 14 such brush has also been applied to the part a, the

page_text: carbon being here guided by means of a small roller. The contact through these
brushes gives but little resistance, while, at the same time, a smooth and uniform
friction is thereby obtained.
The various kinds of mechanism in the lamps shewn are mainly applied for the
purpose of providing for the setting free or releasing and arresting of a strong
motive power in such a manner as not to interfere with, or influence, the movable
clamp. If, by using sufficiently smooth or metallized carbons, or by using the
carbon-clamps just described, but little motive power should be required, the device
may be simplified considerably without causing injurious shocks or friction. As,
for instance, in Figure 15, the lever arın I m acts upon a clamp-catch regulating
the descent of the rod og and, thereby, the pushing forward of the carbons. The
catch may also be constructed as a pawl and og as a rack.
The catch r may also act upon the carbon cd instead of acting upon the rod og,
this arrangement being shewn in Figure 16. In this instance the catch acts at
the same time as a carbon-clamp, the movable part of the clamp being connected
with the lever kl by means of an arm r and a rod or link.
In order to ensure a smooth uniform movement, og in Figure 15 and d in
Figure 16 may be connected with a piston moving in a cylinder filled with any
suitable liquid or with air or other fluid.
Article 8. In some cases the mobility of one of the clamps may be dispensed
with, the carbons being pushed through the clamps and against each other by
means of some constant power. By reason of the difference between the coefficient
of friction of rest and that of motion it will only be possible to get an approxi-
mately constant pressure at the point of contact between the two carbons, if there
is very little friction in the clamps. But, as this is generally not the case, a
construction having a movable clamp must be applied. Yet, in some cases, where
very smooth carbons are used which have either been rubbed with plumbago or
metallized, stationary clamps may be applied. An example of such device is
shown in Figure 17. One carbon is depressed by the weight of the bar or
rod go, the other carbon being raised thereby at the same time by means of a
chain ph ke The device Figure 18 acts in a similar manner, differing only in
that the clamps are here provided with two friction-rollers. The chain may,
if desired, be replaced by any other device whereby the motion of og Figure 17
is changed into exactly the opposite motion, for instance, by two racks and a
gear-wheel.
Simple devices of this kind are particularly well adapted for use in auxiliary or
supplementary lamps, which are used only during such length of time as is
required for inserting fresh carbons in the main lamp. As but little time is
required for such insertion, the pushing forward of the carbons through the clamps
may be dispensed with, in the said auxiliary lamps, short carbons being pressed
against each other by means of a constant power. The devices hereinbefore
described may be applied for this purpose, the clamps being then omitted. The
motive mechanism for the lower carbon may also be dispensed with, since, in most
cases, the change in the position of the light offers no difficulty. Thus the device
Figure 19 is obtained. A device having inclined carbons is shown in Figure 20.
The carbon-holder el turns on an axis land, by means of a spring (or weight), is
drawn towards the other holder. In order to obviate the necessity of having often
to insert fresh carbons, carbons of greater length may be used, as is indicated by
dotted lines in Figure 20, the said carbons being pushed forward a short distance
occasionally. If it be desired to still further simplify this manipulation, the
device having chains as shewn in Figure 1 may be used. The cylinder containing
a liquid, valve-chest and other parts will be omitted, the movement being produced
by hand.
The switching, in of the auxiliary lamps, may also be easily produced
automatically. For this purpose, the armature of an electro-magnet is connected
with the movable carbon, or carbon-holder, for instance, with the lever e

page_text: Figure 20. The electro-magnet is arranged in the circuit conducting the current
to the main lamp. Now, for the time this lamp is in operation, the armature will
remain attracted and the carbons in the auxiliary lamp will be separated, so that
the current cannot pass through the same, notwithstanding the fact that both
carbons are connected with the circuit. But, as soon as the current in the main
lamp is broken, the electro-magnet will release the armature and the carbons of the
auxiliary lamp will make contact.
Article 9. Simple devices like those shewn in Figure 15 may also be used in
combination with considerable motive power, if the power required for clamping
be not supplied through the lever kl, or no power at all be required for this
purpose. The electric current may be used for this purpose, an electro magnet with
an armature providing for the releasing or the electric current being applied as a
motive power. The electro-magnet or motor may be arranged in a shunt or branch
circuit (Figure 21) or in the main circuit (Figure 22). The circuit is connected
with Land L. The carbon-clamp a is connected with L' by means of the frame
of the lamp, while the movable clamp, Figure 21, is connected with L by means
of the lever k l m and a flexible metallic band. If, by reason of the carbons being
consumed, the movable clamp b is raised, the arm 1 m will make contact with the
spring vw, thus establishing a branch circuit or shunt through the electro-magnet
or motor M. The carbons are now pushed forward until the electric connection
between v and m is broken again, the spring vw coming to rest against the
screw u. In Figure 22, the ärm l m is provided with an insulated head at m.
As long as the spring vw makes contact with the screw u, most of the current
will pass through this connection, instead of passing through the electro-magnet or
motor M. But when the electric connection between vand u is broken on moving
the arm m, the whole current must pass through M. In lieu of the clamp b, the
clamp a. or both clamps may be insulated from the frame of the lamp. The
direction of the circuit will be clear from what has been stated, without requiring
any further explanation. The arrangement of the releasing device or of the
motive mechanism may be similar to those above described, as, for instance, in
Figure 7, an electric motor may be used for supplying the motive power.
Article 10. The change of form which the carbons undergo while being consumed
may also be applied for imparting motion to the releasing device at the proper
moment and independently of the movable clamp. For instance, in Figure 23, a
lever-arm u is pressed against the carbon c d by means of a weight or spring.
Now, as the carbon, on being partly consumed, will assume the form shewn in
dotted lines, the lever u will also assume the position shown in dotted lines, and
produce the movement of the releasing device. In order to readily place the
arm in the proper position, the movement is first transmitted to an intermediate
piece, that is to say, to the lever-arm w.
The arm w is loosely mounted upon the shaft u¹, and the motion of the lever u
is imparted to the arm w by an arm secured to the lever u and a binding screw v
passing through the said arm.
In Figure 24 a modification is shown, acting in a manner similar to that of the
arrangement above described. The construction of this modification may be easily
understood from this Figurė.
If the device a of Figure 24 is rigidly connected with the carbon-tlamp, as
described, the arrangement shown in Figure 25 is obtained.
Now, if one or both clamps, of any of the forms of construction of lamps
herein before described, be arranged in this manner, the carbon c d on removing the
arresting-device, will be pushed forward until its movement is limited by the
points ?, r. If the carbons are reduced by consumption, they are forthwith
advanced so that always the same lengths project from the clamps. When both
clamps are provided with the device described, ehch carbon may have its own
motive power, which may be obtained by a weight, spring, hydraulic column or
other suitable means.
Instead of using a spring as in Figure 1, the constant pressure may also be

page_text: produced in any of the lamps by means of a weight as in Figure 5, or by means
of a hydraulic column, or in any other convenient manner.
The
Article 11. In order to ensure a slow and uninterrupted movement of the carbons,
a fly-regulator may be applied in some cases, as shown in Figure 5. The said fly
may be arranged to rotate within a case filled with some suitable liquid, for the
purpose of avoiding a transmission by means of complicated wheel-work.
case may be closed by a tightly fitting lid, as in Figure 5, to prevent the liquid
from flowing out in case of the apparatus being reversed. The shaft of the fly-
regulator may, if desired, be arranged horizontally.
During the norinal operation of the lamps, the carbons will advance but slightly
each time. The fly q, or any similar device employed for the same purpose, will
then act only for a short time and soon become stopped. Accordingly, it will be
sufficient to mount upon the shaft a small fly-wheel, the vis inertia of which
prevents it from rotating too fast at the beginning, and which will be stopped again
before running full speed.
In case the two carbons are very long, then the variations of their weight in
burning away would produce an appreciable difference in the pressure against each
other at their point of contact. This is prevented by means of a chain, Figure 8,
connected to e and guided over pulleys at ¹ and , the other end of the said chain
being secured to the casing p of the clock-work. The weight of the said chain is
calculated to be equal to that of the chain e k and the carbon, at an equal length.
It will be readily understood, therefore, that the lever will always be equally
weighted independently of the length of the carbons. A similar arrangement may
also be employed with all the other forms of construction.
It may happen that, in case of an impediment being offered to the advance of
the carbons, or in case of their being fully consumed, the said carbons will not remain
in contact if the lever be in its highest position, as in Figure 8; all the lamps
included in the same circuit would thus be extinguished. To avoid this incon-
venience, every lamp is provided with a device which allows of short circuiting
the same.
The movable carbon-holder with clamp b is connected to the set-
Screw L by means of a flexible metallic band. The said screw L is insulated from
the casing of the lamp, while the screw L' is electrically connected to the said
casing. The circuit is connected with the screws L and L¹. The carbon-holder
is provided with a projection v which, on raising k will bear against a pin u
secured to the casing, L and L' thus being brought into metallic connection. It
may easily be seen that b and L may, if desired, be brought into metallic connection
with the lamp casing, in which case u and L' must be insulated from the same.
The same arrangement may also be employed in a similar manner with all the
other forms of construction.
Article 12. The herein described method of producing light not depending on the
presence of any distinct kind of gas, each of the lamps, as set forth, may be
employed in an enclosed space from which the air has been exhausted, or which
has been filled with gas of any kind. The purpose of this arrangement is to
prevent the carbon from being consumed. In some cases, it may be found sufficient
only to reduce the consuming process by surrounding the lamp with a casing of
glass to provide against the access of air. The construction of this arrangement
may be similar to that of the receiver and plate of an air-pump. But it may be
observed that part of the lamp itself, for instance, the foot of Figure 5 or
the upper part of the casing Figure 8, may allow of being tightened against
the bell.
As the oxygen of the enclosed air will soon be consumed by the carbon, the
latter will only lose at the commencement and may be advanced by hand, from
time to time, whereby the necessity for applying motive power is avoided. The
movement may be imparted from the outside by means of a rod passing through,
and packed in, a stuffing box. By this simple arrangement another advantage is
obtained, that is to say, the dimensions of the apparatus may be reduced con
siderably and consequently the quantity of oxygen therein will also be inuch

page_text: smaller. By this means, the rate of consumption of the carbon may be so much
reduced that the means for pushing forward or advancing the carbons in the clamps
can be dispensed with. The lamp will then have assumed the form shown in
Figure 8 for auxiliary lamps. Such device is now enclosed in a casing made of
glass only, the electric current being introduced by means of wires of platinum
sealed or fused into the glass. Figure 26 serves to illustrate a specimen of this
kind of lamp. To allow of inserting the lamp proper, the glass casing is divided
into two parts on the line x, y. To the lower part a glass-tube i is sealed supporting
the foot of the lamp. Of the wires L, L' sealed or fused into the glass, the one L
is connected by means of a spiral springs to the movable lever le insulated from
the other parts of the apparatus, while the wire L' is metallically connected to the
lamp-foot f. When the said connections have been duly fitted, the casing x, z, y is
sealed to the lower part on the line x, y. For the purpose of uniting the two parts
by blowing, a glass tube is applied either to the upper or lower part. The sealing
or melting operation is performed while the lamp is burning, for the purpose of
preventing the glass being subsequently cracked through the expansion of the air.
If the movable lever is counterbalanced, as indicated in Figure 26, the lamp will
operate in any position it may assume. All the other forms of construction of the
lamps, as herein before described, may be arranged within and fused into a glass
casing, for instance, that described in article 9. The lamp may be filled with
another gas, such as hydrogen or nitrogen, instead of with air.
The nitrogen gas
may be obtained by placing in the lamp filled with air, or in a glass-globe connected
to the lamp, a small piece of sodium, potassium, or other readily oxidizable metal.
The said metal, becoming heated, will quickly enter into combination with the
oxygen and the resulting oxide will absorb, when cooled down, any vapour or
carbonic acid which may have been developed.
In lamps of this kind an injurious effect is produced by the crumbling or
disintegration of the carbon, the carbon-dust surrounding the incandescent part of
the carbon in the manner of a shade. To obviate this difficulty the upper clamp a,
Figure 27, of the vertical carbons is surrounded by a casing a¹ a¹ (shewn in
section) acting like a chimney and removing the dust by draught. The said
casing may be extended upwards by a pipe and a similar casing may also be
applied to the lower carbon-clamp. A chimney-glass contracted about its middle
and surrounding the carbon-points, as shewn in Figure 28, will increase the
effect.
In a lamp like that shewn in Figure 19, the carbon is surrounded by a chimney.
glass.
In the construction of a lamp like that shewn in Figure 20, it is preferable to
apply a chimney in combination with the apparatus in a reversed position, as
shewn in Figure 29. The chimney is indicated by a' b¹ and opens into a box b¹
above, in which the dust is collected.
Article 13. In the arrangement of lamps herein before described the air may if
desired be exhausted. In order to avoid by means of high rarefaction practically
all the consumption of carbon, a lamp-casing entirely made of glass must be
employed as in the construction shown in Figure 26. The use of a chimney is not
necessary in this arrangement.
During the exhausting operation a current is passed through the lamp in order
to expel by the generation of heat, the gases contained in the carbon. The
intensity of the current is gradually increased until the lamp attains its full
intensity of light; the glass is then closed by sealing while the current continues
to pass.
The movable lever le scarcely receives any motion, the said lever is, however,'
indispensable in order to ensure and maintain the constant and proper pressure, if
slight variations should occur by the changes of temperature or by the pulverization.
or disintegration of the carbon. The axis of rotation & may be substituted or
replaced by one or two flat springs, such as are usually employed for the axis of:
oscillation of a pendulum. If all parts are constructed as lightly as possible, the '

page_text: counterweight of the lever le, Figure 26, may be omitted. The construction will
then be as shewn in Figure 30.
In order to provide for the carbons continuing to be in contact at their points
only, and to avoid their gliding off or passing by each other, semi-circular or thin
flat carbons instead of round ones, may be employed in the forms of construction
shewn in Figures 26, 29 and 30, the flat sides of such carbons being turned
towards each other. In using particularly thin and flat carbons, their elasticity
will become easily perceptible, and in using such carbons, for instance, in the
lamp shown in Figure 30, the actual cause of the pressure created at the point of
contact of the carbons must be attributed to the elasticity of the carbons only.
The springs e, Figure 30, may, therefore, be omitted since the elasticity of the
carbons is sufficient to produce the required pressure at the point of contact, an
arrangement of this kind being shewn in Figure 31, and requiring no further
explanation.
Article 14. If several lamps are switched for quantity it will be of particular
importance for all lamps to have the same resistance. As the proportion of the
resistance of the carbons in a cold and in a heated state is nearly constant in all
carbons of the same kind, it will be necessary only to give the same resistance to
all lamps when in a cold state. This may easily be done by adjusting the length
of the carbons d c, e c before sealing the glass around the lamp.
By varying the length of the carbon in the lamp, the resistance and con-
sequently the illuminating power of the lamp will be changed. Such changes may
be made in a completely fitted lamp of the construction shewn in Figure 32. The
mechanism by which the carbons are advanced in the clamps a and b is similar to
that shewn in Figure 1. Instead of connecting the two chains with a piston n;
the said chains are connected in Figure 32 to a nut o upon a screw-spindle or
mandril p carrying the weight n. On turning or rotating the whole apparatus so
that the screw-spindle palways remains in the horizontal position, the said
spindle will not partake of the rotation on account of the weight n, but the nut o
will turn. In this manner the carbons may be advanced at any desired rate.
provide also for moving the carbons back again, if this be desired, an endless chain
similar to that described in Article 11, may be employed, or each carbon may be
connected to a spring counteracting the chain. as indicated in Figure 32 at ke
and g d:
To
If an iron bar n n mounted transversely upon the screw p, Figure 33, is
substituted for the weight n Figure 32, the screw p may be turned by means of a
magnet or electro-magnet NS. The manner in which the electro-magnet may be
turned by means of the knob A and also the manner in which the electric current
is introduced through two insulated collars having contact-brushes; will be readily
understood from Figure 33. The apparatus may be so arranged that under
normal conditions the electric current passes through the lamp only and not.
through the electro-magnet, the current being passed through the latter, when
required, by means of an ordinary commutator.
The devices illustrated in Figures 32 and 33 may also be employed in com-
bination with lamps filled with air, for the purpose of advancing the carbons when
they have become shortened by consumption.
Article 15. The air may be exhausted by means of ordinary. air-pumps. But the
present invention comprises an arrangement the principal features of which are
shewn in Figure 34.
A cylinder a a a a is closed hermetically at the top by means of a lid, a valve
opening towards the outside being provided in the said lid. Within the said
cylinder a receptacle b c is arranged to slide up and down which receptacle is
provided with packing at b, b. The packing may be of any convenient kind and has
only to resist a relatively slight rarefaction of air as will be seen. A globe or
belle is suspended from the lid of the cylinder a the said globe having a valve
at f. The vessel to be exhausted is connected to the pipe g which pipe is also
connected to the globe or bell and the receptacle b, c. The reflux of air at g is

page_text: stopped by means of an ordinary or a "Toepler" mercurial valve. The receptacle
b, c is filled with mercury. The action will now be readily understood. On
forcing down the receptacle b c by any suitable means, for instance, by means of a
crank shaft and connecting rod, a partial vacuum or a rarefaction of air is produced
within the cylinder a by reason of which air enters the globe or bell e through
the pipe g.
On raising the receptacle bc again the valve at g will be shut and
the air will first be forced through the valve f into the cylinder a whence it will
escape to the outside through the valve d. It will thus be seen that even n
slight rarefaction of the air within the cylinder a will produce a great degree of
rarefaction within the globe or bell e, the quicksilver remaining at a higher level
in e than in the receptacle b c in proportion only to the difference of pressure.
This arrangement affords many advantages inasmuch as the operation is
automatic, the pumping accelerated and but a small quantity of mercury required,
which does not come into contact with india-rubber or with the outside air, the
valve being but slightly weighted and tightening perfectly with the use of only
a small quantity of mercury. Moreover, the whole arrangement is very simple
and not liable to breakage.
Article 16. For securing the lamps and connecting thein with the conducting
wires, the devices shown in Figures 35, 36 and 37 are employed. In a cylindrica!
casing a a, Figure 35, a block b is made to slide, the said block b resting upon a
flange applied to the lower end of the casing a a and projecting inward, a pressure
being exerted upon the block by means of a spiral spring secured within the said
casing or cylinder. The binding posts L L¹ are connected to the spiral springs 8, 8',
the upper ends of which are bent so as to form small hooks. Now, on pressing
the block b upward into the casing or cylinder a, the platinum wires projecting
from the lamp may be easily made, to engage with the hooks of the springs 8, 81.
On releasing the block b the lamp will be held in place, as may be seen from the
Figure. The cylinder a may be secured to a bracket or chandelier by means of a
screw-threaded bolt or trunnion c. The posts L and L' and the spiral springs s
and s¹ must be insulated from each other, but the remaining parts of the device
may be made of any suitable material, such as metal, wood or ebonite. Figure 30
shows, for instance, a casing a, a stamped out of sheet metal. In this modifi-
cation, the trunnion c is formed on the lower end of the block b. Two posts may
also be applied in this modification, but in the device shewn in the drawings one of
the spiral springs 8 is connected to a screw-threaded metallic sleeve d, while the
other spring & extends through the axis of the trunnion c and is connected to a
knob or button e. The electric circuit is completed by a screw-threaded socket d'
having a metallic knob or button e¹, the connection with the lamp being established
by screwing & into d' as will be well understood. In order to prevent the spiral
springs 8, 8, in the apparatus shewn in Figures 35 and 36, from coming
accidentally in contact with each other, the ends of the said springs may be passed
through a small block of wood, ebonite or other suitable, material, to keep the
springs separated, their hooked ends projecting from the block.
In the arrangement shewn in Figure 37, a metallic casing a, a is cemented to
the lower part of the lamp. The bottom of the said casing consists of a disc of
wood, ebonite or similar material carrying at its centre a metallic knob or button c.
The casing a and the knob c are connected to the conducting wires of the lamp.
The casing a is provided with two projecting pins entering a bent or angular slot
of another casing b for locking the one casing to the other. The metallic connection
is established through the casing band the spiral spring 8. The tendency of the
spiral spring to press the lamp upwards and out of the casing b is utilized for
holding the former more securely within the latter, by constructing the said
angular slot so that its lateral part is slightly inclined in an upward direction.
Article 17. If a lamp is to be secured to a pivoted holder or bracket as shewn in
Figure 38, the electric circuit may be established through the joints A and B by
means of the device shewn in Figure 39. This device consists of two cylindrical
boxes or pieces of wood, ebonite or similar material, one of which has a cylindrical

page_text: and the other an annular recess. In each of the said recesses the conducting wires
are arranged in the form of coiled springs, which, as indicated in Figure 38, are
either soldered or connected by posts to the wires of the circuit. This arrangement
however, allows of an alternate or reciprocating motion only, while the modification
shewn in Figure 40 permits a rotary motion always in the same direction. In
this case the electric connection is established by means of conical boxes fitting
upon each other thus providing against oxidation of the surfaces of contact and
preventing non-conducting substances from depositing upon the said surfaces.
Article 18. The device shown in Figure 41 serves to close and break the circuit at
will. Upon a cone a of wood, ebonite or other suitable material, two metal plates
a¹a are mounted. The cone a is adjusted within a conical cavity of the block
b, b, two metal plates corresponding exactly with the plates a¹ a' being inserted
in the said cavity. The block b, b is made of insulating material and the metallic
plates are secured to the same by means of binding posts c, c, and are thus brought
into electrical connection with the circuit. If the cone a is in the position to make
its plates a¹ a¹ cover the corresponding plates in the cavity of the block b, b, the
circuit will be broken, while on turning the said cone 90°, the plates a, a will
establish the electric connection between the posts c, c. In order to compel the
cone a to remain stationary only when it occupies one of the said two positions,
and to establish, at the same time, the necessary pressure between the cone a and
the block b, a coiled spring is applied to press against the pin d. It will be readily
understood from the form of the said spring as shown in the drawings; that when
but a slight turn is given to the cone the latter will be pressed back again into
its former position. But if the turning of the said cone is continued until the
pin d strikes against the pin e then the coiled spring will glide over the pin d
so that the latter will now be pressed in the opposite direction.
One more pin
similar to e must be provided to limit the movement of the cone a to one quarter
of a revolution.
The form of the surfaces of contact shown is chosen for the same purpose as has
been set forth in the previous article with reference to Figure 40, that is to say, in
case of the circuit being broken for a long time, oxidation is not liable to take
place, as the said contact surfaces cover each other perfectly. In lieu of conical
contact surfaces, flat discs may be applied, also in the apparatus shewn in
Figure 40.
The fact must be observed that in the several devices described with reference
to Figures 16, 17 and 18 of the drawings both conducting wires are insulated. If
but one insulated conductor is thought to suffice, the construction in some respect
may be simplified, as then, for instance, the one half of Figure 39 may be dispensed
with, the holder or bracket Figure 38 being made use of for the return current.
Article 19. In some cases, the line is connected to an apparatus substantially as
shown in Figure 42 of the drawings for the purpose of providing against the
destruction of the lamp and the conductor, if from any cause, the current should
become too intense. The operation of this apparatus is based upon the same
principle as the thin wire in lightning arresters used in telegraphy. But in the
present case it is desirable to have the least possible resistance in the circuit
while, at the same time, the intervals of interruption must not be too short, in
order to prevent the formation of a Voltaic arc. In the usual construction the one
of these conditions is excluded by the other, but according to Figure 42 both
conditions are fulfilled. The circuit from L to L' is completed by means of a
metallic spring having the metallic block a, fusible piece of metal b and metallic
block c.
The piece 6 melting away, the block a will assume the position indicated
by dotted lines, both by reason of the tendency of the spring to straighten itself
again and by reason of the weight of the block a. The block a may, therefore, be
made very small, a wide break being nevertheless obtained. The piece b may
consist of any convenient readily fusible wire or sheet-metal or metallic alloy, yet
it is deemed preferable to widen it a little near its ends as indicated by A B in
order to ensure a better contact by clamping it at its broad ends.

page_text: Article 20. As concerns the metals and other materials to be used for the
construction of the various parts, the common rule is generally adopted.
Attention must, however, be drawn to the fact that pure nickel has been found to
be a substance particularly well adapted for the carbon-clamps, not only as concerns
the lamps to be used in a vacuum, but particularly as regards the lamps to be
used in the air for the reason that the said metal combines with hardness and a
high degree of fusibility a great power of resistance to oxidation. The insulation
of the parts may be effected in the usual manner, only it will be found preferable
to use glass, stone, mica, or the like for the lamps referred to in articles 12, 13
and 14. The glass globes of the lamps constructed in accordance with articles 12,
13 and 14 may, partly or wholly, be inade opaque by grinding, or they may be
made of opal-glass. The present invention comprises the employment of a ribbed
or corrugated surface for vacuum lamps. Both the last. mentioned forms of lamps
are usually particularly well adapted for dispersing the electric light without any
material loss. The said invention also comprises a glass ribbed on both sides, but
on one side crosswise of the direction of the ribs on the other side.
Article 21. For the carbon rods, all the usual kinds may be used. Since in lamps
having carbon-clamps a small part only of the carbon is arranged in the circuit,
even a poorly conducting carbon unfit and unqualified for common purposes, may
be utilized. In some cases it may even be preferable to use carbon of high resistance,
that is to say, when the light is intended to be produced at a great distance from
the machine. To this end the carbonaceous paste serving for the manufacture of
the carbons, may be mixed with poorly conducting refractory substances, such as
the so-called earths (terra), like lime (calcareous earth), alumina, or some metalloids
and the combinations therewith, like boron nitride (borstickstof) or silicon nitride
(siliciumstickstof). Furthermore, by selecting the proper kinds of carbonaceous
substances in the shape of coal or plumbago, all subsequent mixing may be
dispensed with and a poorly conducting refractory carbon produced in a direct
manner.
Good conduction may also be a desirable property. As, for instance, in using
the carbon-clamps described in article 7, a good conducting surface will be
preferable. To this end the carbons may be metallized, a very thin galvanic film
being sufficient for the purpose, also a film of a readily fusible metal like silver or
zinc, because in the present case provision is not intended to be made for preventing
combustion, which is the chief object for other purposes. Also a metallic coating
of thicker proportions may be appropriate, because in such case mainly the metal
will conduct the current to near the point of contact of the two carbons. In this
instance likewise, the readily fusible metals may be used with advantage, since
carbons of this kind will be found preferable with the forms of construction having
no carbon-clamp as described in article 8, the latter being then replaceed by the
metallic box. By applying such carbons, the devices herein before referred to as
auxiliary lamps may also be adapted to operate for a longer period of time.
The object attained by means of a good conducting covering or coating of the
carbon-rods, that is to say, the object of permitting the employment of long
carbon-rods in lamps having no carbon-clamps, can also be attained by providing
a common good conducting carbon with a poorly conducting core.
In this instance,
therefore, the same effect is produced by the good conducting outside carbon, as
compared with the badly conducting core, as that produced in the preceding
instance by the metallic coating as compared with the common carbon. The only
difference is that the present arrangement requires a current of higher tension
which in some cases may be very desirable. The manner in which such core-
carbons are employed is, therefore, the same as has been herein before described
with reference to the metallized carbons. A compound of carbon and nou-
conducting material, or simply poorly conducting substances may be employed for
the poorly conducting core substantially in the manner set forth at the beginning
of the present article. It is evident that the core-carbons also may be metallized

page_text: with advantage. Moreover, the carbons of one lamp may be different, as for
instance one lamp may contain one carbon having a clamp, and one core-carbon.
The manufacture of the core-carbons may be effected by first forming a good
conducting hollow carbon-rod and, then, inserting therein a poorly conducting rod.
It is preferable, moreover, to soak or impregnate both rods with syrup, tar or the
like and to anneal them, which process may be repeated several times. By
annealing a poorly conducting carbon in carbureted hydrogen gas, a good
conducting coating may be formed upon the same.
The carbon may if desired be pressed simultaneously with the core in one
operation, the device shewn in Figure 43 or that shewn in Figure 44 being attached
to the carbon-press. The chamber A contains the good-conducting material, while
the good conducting carbon-tube is pressed through the annular opening a, a, the
hollow space at the same time being filled with poorly conducting material through
the mouth b of the pipe B. A thread of cotton or the like may also be introduced
through B in Figure 44. This thread may be combined with such substances as
will cause a more or less poorly conducting core to be formed after the annealing
process has been completed. In the case of lamps in which the carbons are
arranged in an inclined position, the poorly conducting material may be applied to
that side where the carbons are in contact with each other.
Article 22. It is not necessary for the carbons which are used in a vacuum or after
the air has been excluded from the lamps of articles 12, 13 and 14, to be of a
refractory nature. Carbons which operate well in the air, may be wholly worthless
in a vacuum, and vice versa. It may be adopted as a general rule that a
considerable homogeneity is required for such carbons as are intended to be used
in a vacuum, porosity not being injurious, while the contrary is the case with
lamps that are intended for use in the open air, for the reason that the porosity
will permit the entrance of air into the interior of the carbon and thus promote
the consumption. In the air, rods made of coal-dust combined with a cement may
operate well, while, in a vacuum, rods prepared without the use of such cement,
inay often be preferable, as for instance rods obtained by carbonizing vegetable
substances, such as wood, paper or the like. Thus the rods may be cut out of
wood, paper or parchment and annealed in coal dust or in a retort containing
carbureted hydrogen gas. There may also a pulp be made of the fibres of wood
or paper and water. By adding sulphuric acid, chloride of zinc or ammoniacal
copper (kupferoxydammoniak), the fibres are transformed into vegetable parchment
in any well known manner, whereupon they are thoroughly washed and by means
of pressing formed into rods of any convenient sectional form. For poorly
conducting carbons, other substances may be added to this material, or carbons
having a core may be made of the same in the manner set forth in the preceding
article. Silicium, boron or black diamond may be used as poorly conducting
substances since in this instance the cost is of but little consequence, the quantity
required being so small and not even being consumed. Metallized and hollow
carbons may also be employed.
The carbon formed upon the inner walls of retorts employed in the manufacture
of gas, would also be well adapted for the purposes of this invention, were it not
for the impure state in which the said carbon is obtained, which renders its
employment impracticable except in some very rare cases. From pure substances,
however, very good carbons may be obtained in a similar manner by distilling tar
or similar material through a red-hot pipe. The carbon formed upon the inner
walls of the said pipe is far too expensive for use in the air, but for vacuum-lamps
this is of uo importance, and from this carbon properly shaped rods may be readily
cut out. In a similar manner good carbon is obtained by annealing in carbureted
hydrogen, metallic wire or sheet-metal by means of galvanic currents.
Also the carbon baked in the usual manner out of coal-dust may be made use of
in a vacuum, provided the carbon itself and the cement have sufficient resistance.
Upou the whole, but little can be said on this subject since the coals of trade differ

page_text: materially, and so in each case the proper proportion and the proper cement must
be found out empirically, for the same cement such as syrup, tar or gum and so
forth, will often produce entirely different results when combined with different
coal. A carbon of this kind thus baked together may be made most durable by
being annealed in carbureted hydrogen. Lamp-black combined with syrup and tar
will also produce a good carbon.
Or a
If, in lamps constructed according to articles 12, 13 and 14, non-metallized
carbons be used, still the end which is held by means of clamping may be provided
with a galvanic coating in order to establish a good conducting connection.
piece of thin sheet-metal may be bent around the carbon so that part of the said metal
projects a short distance beyond the carbon, and then both may be soldered
together by means of the galvanic current. The projecting part of the metal is
then secured by clamping and may thus be clamped very tightly without there
being any danger of the carbons being broken during the clamping process. Or
by means of a paste composed of plumbago and gum or any other cement, the
carbon rods can be secured to the carbon-holders. Thus by means of this paste
(or by means of galvano-plastics) the carbons in the lamp shewn in Figure 31 may
be connected with the platinum-wires in a direct manner and the binding-screws
shewn in the said Figure be dispensed with. On being heated during the
evacuating process the cement will be decomposed. The volatile substances being
then removed, the final composition will consist of carbon only.
Having thus fully described the said Invention as communicated to me by
my foreign correspondent and the manner of performing the same I wish it
understood that I claim :-
First. An electric lamp or lighting apparatus wherein two carbon points are kept
continually in contact under constant pressure, each or either of the carbons being
arranged to be pushed through a clamp forming a conductor for the electric current,
which clamp may or may not be provided with metallic brushes or rollers, and one
clamp being movable relatively to the other clamp on a certain trajectory, while
both are pressed toward each other by a spring, weight or other suitable means,
the pushing forward or advancing of the carbon in the movable clamp being effected
by a device such as a flexible coupling which will not interfere with the movability
of the said clamp, substantially as, and for the purpose, set forth.
Second. The arrangement, in the said lamp, whereby the releasing or arresting
of the weight, spring or other motor provided for advancing the carbon or carbons
through the clamp or clamps is effected by the motion of the clamp or by the change
in form which the carbon undergoes while being consumed, substantially as, and .
for the purpose, set forth.
Third. The modification of the said lamp wherein the carbon-clamps are rigidly
connected to the lamp-frame and the carbons are pushed through the clamps and
against each other by means of a convenient constant power, any suitable device
being provided whereby the motion of one carbon will cause the other carbon to
move in the opposite direction, substantially as set forth.
Fourth. The modification of the said lamp wherein the carbon points are each
guided in a certain trajectory and are held in contact with each other by means of
any convenient constant power, substantially as set forth.
Fifth. The modification of the said lamp wherein the carbons are placed in an
enclosed space filled with air or other gas, or in a vacuum, substantially as set
forth.
Sixth. The air-pumping device described in article 15, which device consists
essentially of a globe or bell enclosed in a cylinder, the lower part of which
consists of a movable receptacle containing mercury, substantially as, and for the
purpose, specified.
Seventh. The device constructed according to either of the forms or modifications
described in articles 16, 17, and 18, and illustrated in Figures 35 to 41, for estab-
lishing the connection between the lamps and the circuit, and for making and
breaking such connection at will.

page_text: Eighth. The device for protecting the lamps and the line from destruction by too
intense currents, comprising a piece of metal which, on the current attaining a
certain maximum intensity, is fused thereby and releases a spring or weight
connected therewith, this causing the circuit to be widely broken, substantially as
set forth.
Ninth. In lamps constructed according to the first, second, third, and fourth
claiming clauses, the employment of the various carbons described, such as poorly
conducting or metallized carbons, carbons having cores, or semi-circular or flat
carbons, the last named carbons usually occupying an inclined position relatively to
each other and having their broad sides facing each other, the said lamps being
provided with mechanism for imparting to the carbon a constant pressure, or the
constant pressure at the point of contact being produced by the elasticity of the
carbon, that is to say, the means for imparting the constant pressure being
constituted by the peculiar shape of the carbon itself.
In witness whereof I the said William Robert Lake have hereunto set my hand
and seal this Fourth day of December in the year of Our Lord one thousand
eight hundred and eighty three.