IMPROVEMENTS IN ELECTRIC INCAN- DESCENCE LAMPS
Year: 1883

page_text: LETTERS PATENT to Alexandor Melville Clark of the firm of A. M and W. Clark
of 53 Chancery Lane in the County of Middlesex Fellow of the Institute of
Patent Agents for an Invention of IMPROVEMENTS IN ELECTRIC INCAN-
DESCENCE LAMPS communicated to him from abroad by Jean Marie Anatole
Gérard-Lescuyer of Paris, France
PROVISIONAL SPECIFICATION left by the said Alexander Melville Clark
at the 'Office of the Commissioners of Patents on the 15th June 1883.
ALEXANDER MELVILLE CLARK of the firm of A M and W Clark of 53 Chancery
Lane in the County of Middlesex Fellow of the Institute of Patent Agents
"IMPROVEMENTS IN ELECTRIC INCANDESCENCE LAMPS." [communicated to him
from abroad by Jean Marie Anatole Gérard-Lescuyer of Paris, France]
This Invention relates to improvements in electric incandescence lamps and has
for its object to enable fine carbon pencils to be employed therein and to obtain a
degree of durability and illuminating power hitherto unattainable in such lamps
and to avoid the blackening of the globes caused by the dissociation of the small
quantity of carbonic acid (which is always formed however complete the vacuum
may be) by reason of the cooling of the globe.
One arrangement consists of a pair of fine carbon pencils inclined so as to cross
one another near the points the said carbons being connected at the crossing point
by traversing a hole in a small carbon disc which the carbons enter at opposite
sides so that it lies in a plane between them. The contact between the pencils
and the disc may be better ensured by making the hole larger so that the disc
becomes a mere ring and filling it with a small spherical mass of carbonaceous
paste which is transfixed by the carbons and thus unites them with the disc. In
both these lamps the disc or the disc and sphere becomes incandescent with the
carbons and owing to its position it acts as a reflector projecting the light in the
direction of the plane of the carbons which in lamps hitherto made is the direction
of least illumination.

page_text: "
In another arrangement the disc or ring is dispensed with and the carbons are
connected at the points which meet at an acute angle, by a small ball of carbon-
aceous paste in which the points are embedded. Several pairs of carbons thus
connected may be placed parallel to one another in the same globe or they may
cross one another like the different diameters of a circle. The platinum wires may
be connected so that the carbons may be arranged in multiple arc or in series.
The arrangement preferred is one in which two pairs of carbons are so arranged
that the carbons correspond to the arrises of a pyramid the result of which is that
_the illuminating surface is equal for all points of the horizon and the pyramid has
the appearance of a real-flame.
The carbons are mounted in small carbon sockets-into-which they are tightly
driven or cemented with a carbonaceous paste and the platinum wires are also-
embedded in or encircle spirally the bottoms of these sockets good contact being
ensured in this case also by a little carbonaceous paste
In order to prevent or considerably retard the blackening of the globes of
incandescence lamps, the globe is enveloped in an outer globe also of glass sealed
or cemented onto the neck of the other one. The space intervening between the
two globes contains air or other gas which being in a stagnant condition prevents
the cooling and consequently the blackening of the inner globe.

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
15th December 1883.
ALEXANDER MELVILLE CLARK of the firm of A. M. and W. Clark of 53 Chancery
Lane in the County of Middlesex Fellow of the Institute of Patent Agents
"IMPROVEMENTS IN ELECTRIC INCANDESCENCE LAMPS." A communication to me
from abroad by Jean Marie Anatolo Gérard-Lescuyer of Paris, France.
This Invention relates to improvements in electric incandescence lamps and has
for its object to enable fine carbon pencils of commerce to be employed therein and
to obtain a degree of durability and illuminating power hitherto unattainable in
such lamps and to avoid the blackening of the globes caused by the dissociation of
the small quantity of carbonic acid (which is always formed however complete tho
vacuum may be) by reason of the cooling of the globe.
In order that this Invention may be more readily understood I have illustrated
it in the accompanying drawings and will proceed to describe it with reference
thereto. Figure 1 reprosents in perspective an arrangement which consists of a
pair of straight fine carbon pencils c c inclined so as to cross one another near the
points, the said carbons being connected at the crossing point by traversing a hole
in a small carbon disc d which the carbons c enter at opposite sides so that the
disc lies in a plane between them. The carbons should fit the disc tightly to
ensure contact between the pencils c and the disc d but a better contact may bo
obtained by the means represented in Figure 2, which consists in making the hole
so much larger that the disc becomes a mere ring, and filling it with a small
spherical mass of carbonaceous paste a which is transfixed by the carbons and thus
unites them with the disc. In both those cases the disc or the disc and sphere
becomes incandescent together with the carbons and owing to its position it acts
as a reflector projecting the light in the direction of the plane of the carbons which
in lamps hitherto made is the direction of least illumination.
Figures 3. 4. 5. and 9 illustrate another mode of uniting the carbon pencils
which consists in dispensing with the disc or ring and connecting the carbons at
the points at which they meet at an angle, by a small ball of carbonaceous paste a
wherein the points are embedded. Several pairs of carbons thus connected may
be placed within the same globe and arranged or combined in any of the ways
berein described, the carbons being arranged in multiple arc or in series as desired.
In the arrangement shown in Figure 4 the two pairs of carbons are inclined
towards cach other until they correspond approximately to the arrises of a pyramid.
In Figure 5 they are parallel to one another. In Figure 9 more than two carbon
pencils are united in series by means of small balls of carbonaceous paste as above
described. In this case the two inclined carbon pencils c aro each united to a
return pencil c¹ extending towards the supporting sockets of the carbons c and
terminating opposite a point about midway between said sockets, the lower ends
of these two return pencils c' being connected by a short cross pencil c² passing
between the carbons c, all these pencils being connected together by carbonaceous
paste a as before explained. The carbons c are in all cases mounted in small
carbon sockets b into which they are tightly driven or cemented with a carbonaceous
paste and the platinum wires e are also embedded in the lower ends of these
sockets as in Figure 7, or encircle. the same spirally as in Figure 6, good contact
being ensured in this case also by a little carbonaceous paste.
Figure 8 illustrates a method of preventing or considerably retarding the
blackening of the globes of incandescence lamps. It consists in enveloping the
globe (which contains the carbons arranged in any of the ways above described

page_text: or in any other suitable manner, and which is exhausted in the usual way) in an
outer glass globe g sealed or cemented onto the neck of the inner one f. The
space intervening between the two globes ƒ and g contains air or other gas which
being in a stagnant condition, prevents the cooling of the inner globe ƒ and
consequently prevents it becoming blackened by the dissociation of the carbonic
acid contained in the inner globe.
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
hereinbefore in part recited-Letters-Patent_is_
1 In an incandescence lamp, the employment of fine carbon pencils of commerce-
in combination with a disc of carbon whereby they are united, substantially as
described and illustrated in Figure 1.
2nd In an incandescence lamp, the employment of fine carbon pencils of commerce
united by small masses of carbonaceous paste and arranged in the various ways,
substantially as herein shown and described.
3rd The mode of mounting the carbons upon the conducting wires by means of
a carbon socket combined therewith, substantially as herein described and illustrated
in Figures 6 and 7.
4th The method of preventing the cooling of the globe of an incandescence lamp
by enclosing it in an external globe, the intervening space being filled with air or
gas forming a nonconducting jacket as illustrated in Figure 8 for the purpose
specified.
-
In Witness whereof I the said Alexander Melville Clark have hereunto set my
hand and seal this fifteenth day of December, A.D. 1883.
A
CADIZ
1