IMPROVE- MENTS IN MEANS OR APPARATUS FOR PRODUCING THE ELECTRIC LIGHT
Year: 1880

page_text: LETTERS PATENT to Alexander Melville Clark, of 53, Chancery Lane, in the
County of Middlesex, Patent Agent, for an Invention of "IMPROVE-
MENTS IN MEANS OR APPARATUS FOR PRODUCING THE ELECTRIC LIGHT."
A communication from abroad by Léonard Jules Bouteilloux, Doctor of
Medicine, and William Laing, Gentleman, both of Paris, France.
PROVISIONAL SPECIFICATION left by the said Alexander Melville Clark
at the Office of the Commissioners of Patents on the 25th February 1880.
ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of
Middlesex, Patent Agent. "IMPROVEMENTS IN MEANS OR APPARATUS FOR PRO-
DUCING THE ELECTRIC LIGHT." [A communication from abroad by Léonard Jules
Bouteilloux, Doctor of Medicine, and William Laing, Gentleman, both of Paris,
France.]
This Invention relates to an electric lamp in which the carbons are regulated
automatically by the action of gravity, a special arrangement of the carbons or
electrodes being employed, consisting of an ordinary carbon and a carbon having a
central core of non-conducting material, with the centre of which the point of the
other carbon is in contact, the weight of the one resting upon the other.
I am aware that two conductors have before been employed, each having non-
conducting cores, but in this case it happened that the carbons resting one upon
the other the interpolary interval was reduced to zero, and the voltaic arc was no
longer formed. In this improved lamp however the solid carbon is in contact with
the centre of the non-conducting core of the other carbon, and the voltaic arc
extends between the point of the solid carbon and the circumference of the annular
carbon.
The regulation of the carbons is effected automatically by the more or less rapid
fusion of the non-conducting core according to the intensity of the current, at same
time that the interval between the poles is always maintained, and is never less
than the radius of the central non-conducting core.
In order that the Invention may be more readily understood I have illustrated
in the accompanying Drawings one example of the improved lamp of this Invention.
Figure 1 is an elevation of the lamp; Figure 2, a vertical section of the upper

page_text: carbon bolder; Figure 3, a similar section of the lower carbon holder; and Figure 4
a horizontal section of the same taken on line 1-2, Figure 3. Figure 5 shows on
a larger scale the mode of contact of the point of the solid carbon with the non-
conducting core of the other carbon, whereby the reduction of the interpolary
interval to zero, and the consequent extinction of the luminous are, are prevented.
The lamp suspension or frame is represented of the lyre form common in gas
lighting, and consisting of an upper part a and a lower part b made of metal or
other suitable material united by two curved arms or branches c made of any
suitable nonconducting material, or the arms e may be of metal and the parts a, b,
be made of nonconducting material; or the whole frame may be of metal and the
carbon holders only be insulated. The part b is provided with a clip or holder d,
consisting of a socket with four longitudinal slits, as shown in Figure 4, and screw-
threaded on its exterior, in which bolder the lower carbon e is secured by a nut f
The upper carbon g is mounted in a similar holder h screwthreaded, and provided
with a nut i, and capable of sliding freely through a socket k on the part a of the
frame, so that the carbon g rests by its own gravity upon the lower one. Any
other means of mounting the carbons in their holders may be employed. The
lower carbon e is made with a core of nonconducting material, upon the centre of
which the point of carbon g rests, and which core is consumed together with the
carbons. It also remains luminous even after the extinction of the arc, and if the
current continues to flow the core melts and volatilises, and the carbons approach
each other until the arc is re-established.
The carbons may be of various diameters, and a certain number of them may be
grouped together in the same apparatus.
It will be seen that with the above arrangement of carbons the interpolar
distance can never be reduced to zero, as would be the case if both carbons had a
non-conducting core, but is always at least equal to the radial distance m, n,
Figure 5.
The lamp frame may be of any other form than that shown, and if, for example,
it be desired to enclose the light in a ground glass globe the carbon holders may
be carried upon the globe itself, which would serve to insulate them from one
another. This arrangement of carbons may also be employed in existing lamps of
all kinds, and the light may be directed where required by any arrangement of
.reflector.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Alexander Melville Clark in the Great Seal Patent Office on the
25th August 1880.
ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of
Middlesex, Patent Agent. "IMPROVEMENTS IN MEANS OR APPARATUS FOR PRO-
DUCING THE ELECTRIC LIGHT." A communication from abroad by Léonard Jules
Bouteilloux, Doctor of Medicine, and William Laing, Gentleman, both of Paris,
France.
This Invention relates to an improved arrangement of electric lamp in which
the carbons are regulated automatically by the action of gravity, a special arrange-
ment of the carbons or electrodes being also employed, consisting of an ordinary
carbon and a carbon having a central core of non-conducting material, with the
centre of which the point of the other carbon is in contact, the weight of the one
resting upon the other.
I am aware that two conductors have before been employed, each having a non-
conducting core, but in this case it happened that the carbons resting one upon
the other the interpolary interval was reduced to zero, and the voltaic arc was no
longer formed. In this improved lamp however the solid carbon is in contact with
the centre of the non-conducting core of the other carbon, and the voltaic arc
extends between the point of the solid carbon and the circumference of the annular
carbon.
The regulation of the carbons is effected automatically by the more or less rapid
fusion of the non-conducting core, according to the intensity of the current, while
the interval between the poles is always maintained, and is never less than the
radius of the central non-conducting core.
In order that the Invention may be more readily understood I have illustrated
in the accompanying Drawings one example of the improved lamp of this Invention.
Figure 1 is an elevation of the lamp; Figure 2, a vertical section of the upper
carbon holder; Figure 3, a similar section of the lower carbon holder; and Figure 4,
a horizontal section of the same taken on line 1-2, Figure 3. Figure 5 shows on
a larger scale the mode of contact of the point of the solid carbon with the non-
conducting core of the other carbon, whereby the reduction of the interpolary
interval to zero, and the consequent extinction of the luminous arc, are prevented.
In all these Figures the same letters of reference indicate like parts.
The lamp suspension or frame is represented of the lyre form common in gas
lighting, and consisting of an upper part a and a lower part b made of metal or
other suitable material united by two curved arms or branches c made of any
suitable non-conducting material; or the arms c may be of metal and the parts a, b,
be made of non-conducting material, or the whole frame may be of metal and the
carbon holders only be insulated. The part b is provided with a holder d, con-
sisting of a socket with four longitudinal slits, as shown in Figure 4, and screw-
threaded on its exterior, in which holder the lower carbon e is secured by a nut f
The upper carbon g is mounted in a similar holder h also screwthreaded, and
provided with a nut and capable of sliding freely through a socket on the
part a of the frame, so that the carbon g rests by its own gravity upon the lower
one. Any other means of mounting the carbons in. their holders may however bo
employed. The lower carbon e is made with a core of non-conducting material,
upon the centre of which the point of carbon g rests, and which core is consumed
together with the carbons. It also remains luminous even after the extinction of
the arc, and if the current continues to flow the core melts and volatilises, and the
carbons approach each other until the arc is re-established. The carbons may be
of various diameters, and a certain number of them may be grouped together in
the same apparatus.
It will be seen that with the above arrangement of carbons the interpolar
distance can never be reduced to zero, as would be the case if both carbons had a

page_text: non-conducting core, but is always at least equal to the radial distance m, n,
Figure 5.
The lamp frame may be of any other form than that shown, and if, for example,
it be desired to enclose the light in a ground glass globe the carbon holders may
be carried upon the globo itself, which would serve to insulate them from one
another. This arrangement of carbons may also be employed in existing lamps of
all kinds, and the light may be directed where required by any kind of
reflector. All materials are here assumed to be non-conducting which do not
readily transmit the current, but which do notwithstanding contain a certain
proportion of conducting matter, while even conducting substances when so
arranged as to prevent the passage of the current are also considered as non-
conducting. For example, in certain cases it would be of advantage to place a
stick of carbon p in the centre of the non-conducting core, as shown in Figure 6,
which carbon being insulated is not traversed by the current, the arc extending
between the upper carbon g and the tubular carbon q, as represented in Figure 7.
In this Figure a counterweight is shown for maintaining the lower carbon in
contact with the upper one. Any other equivalent arrangement may be adopted,
and the position of the carbons may also be reversed. In Figure 8 an electric lamp
of this kind is represented, in which the luminous focus is maintained at a certain
fixed point by means of cords or chains 8, guide pulleys t, and a single counter-
weight u. The apparatus may however be otherwise varied in detail according to
circumstances.
The tubular carbon forming one of the electrodes filled with non-conducting
material, as before mentioned, inay be replaced by a series of sticks of carbon
surrounding a central non-conducting core.
Having described the nature of the said Invention and the manner of performing
the same, I declare that what I claim as the Invention to be protected by the
herein before in part recited Letters Patent is,―
1st. In an electric lamp the employment in combination with an ordinary
carbon electrode of a second electrode, consisting of a tubular carbon (or of a
number of carbon sticks) surrounding either a simple non-conducting core or a core
containing a stick of carbon, which is thereby insulated, substantially as shown
and described for the purpose specified.
2nd. In an electric lamp, in which the electrodes are composed of an ordinary
carbon and a carbon having a non-conducting core, the combination of said
electrodes with holder d and nut f, holder h, nut i, and socket k, the whole being
mounted in a lyre shaped or other suspension frame, as described.
3rd. In an electric lamp, in which the electrodes are composed of an ordinary
carbon and a carbon having a non-conducting core, the employinent in combination
with the stationary electrode of a counterweight or its equivalent for maintaining
the second electrode in constant contact therewith, substantially as described and
represented in Figure 7.
4th. In an electric lamp, in which the clectrodes are composed of an ordinary
carbon and a carbon having a non-conducting core, the combination of cords or
chains and a counterweight or its equivalent, whereby the said electrodes are
pressed against each other, so as to maintain the luminous focus always in the
same position, substantially as described and represented in Figuro 8.
In witness whereof, I, the said Alexander Melville Clark, have hereunto
set my hand and seal, this Twenty fourth day of August, in the year of our
Lord One thousand eight hundred and eighty.