IMPROVE- MENTS IN ELECTRIC LAMPS
Year: 1878

page_text: LETTERS PATENT to Edward Thomas Hughes, of the Firm of Hughes and Son,
Patent Agents, 123, Chancery Lane, London, for the Invention of "IMPROVE-
MENTS IN ELECTRIC LAMPS," A communication from abroad by William
Wallace, of Ansonia, County of New Haven and State of Connecticut, United
States of America
COMPLETE SPECIFICATION filed by the said Edward Thomas Hughes at the
Office of the Commissioners of Patents on the 18th January 1878.
"
EDWARD THOMAS HUGHES, of the Firm of Hughes and Son, Patent Agents, 123,
Chancery Lane, London. IMPROVEMENTS IN ELECTRIC LAMPS." A communication
from abroad by William Wallace, of Ansonia, County of New Haven and State of
Connecticut, United States of America.
This Invention relates to improvements in electric lighting apparatus, and par-
ticularly to a device which may be arranged at any desirable point, and which
employ two pieces of carbon nearly approaching each other, and between which the
electric arc is formed, and where the carbons are consumed.
In the usual construction these carbons have been in pencil shape, square or
polygonal, and arranged so that they come in the axial line of each other, and so
that the point of one is presented to the point of the other.
In such a lamp the carbon will only burn while the points of the two are within
a certain distance of each other; as soon as that distance exceeded the current is
broken and the light is extinguished.
Various devices have been resorted to to cause the carbons to automatically
approach each other as they are consumed, and so as to hold them always in the
proper relative position to each other; but these devices are necessarily compli-
cated and expensive, rendering such a lamp impracticable for general use.
The object of this Invention is to overcome the necessity of this constant re-
adjustment of the carbons, and it consists in a pair of carbons having an extended
working edge, arranged so as to bring their edges substantially parallel to each

page_text: other and to the said carbons, each held in a suitable support and each connected to
its respective pole of the electric power, and so that the circuit may be made at any
point in the said extended or parallel edges of said carbons, as more fully herein-
after described.
In illustration the simplest arrangement is shown, in which A represents a frame
of wood or other suitable material in dimensions according to the purpose for which
the lamp is intended; across this frame are two metallic bars B, C, on each of which
a suitable clamp or holder D is arranged to receive the respective carbons E, F.
These carbons are made in the form of thin plates, and so as to present the two
edges a parallel to each other, or nearly so.
From one pole of the electric power a wire d is brought to the bar B or to the
support for the carbon E, and to the other bar C or support for the carbon Fa
wire e is brought from the other pole, hence when the electricity is applied the
space between the two carbons E, F, forms the arc in which the circuit is made. To
make the circuit and start the light the electricity is applied, and with any suitable
device the circuit is made at any point between the two edges of the carbon, pre-
ferably beginning at one end. The flame will burn at the point at which it is
ignited until the carbon is consumed at that point, then it will attack the nearest
point, working back and forth on the edge generally for a short distance until so
much of the carbon over that portion is consumed as to nearly break the circuit ;
this will force the current to an adjacent point where a less arc is found, and will so
continue back and forth until the entire edges of the carbons are consumed to such
an extent that the circuit can no longer be maintained between the two edges; but
the time which is necessary to so far consume these extended edges is so great that
light after such a time would not usually be desired, and in consequence of such
extended edges and continued burning along those edges the constant re-adjustment
of the carbons and the mechanism necessary to render such adjustment is avoided,
and a lamp produced having equal brilliancy to any electric light, thoroughly prac-
ticable in its operation, and so cheap in its construction as to render it practicable
for general purposes.
In practice the frame is suspended at the point from which it is desired that the
light shall proceed, or may be arranged upon a supporting stand, or an entirely
different construction for supporting the carbon holders may be employed without
departing from this Invention, it only being essential that there shall be two carbons,
each with extended edges and parallel to each other, and each connected with its
respective pole. When so much of the carbon is consumed they may be replaced or
may be readjusted.
Having now described the nature of the said Invention, and the manner in which
the same may be used or carried into effect, I would observe in conclusion that what
I claim as the Invention, is the herein described electric lamp, consisting of a pair
of carbons, each presenting an extended edge parallel to each other, combined with
means for holding said carbon, and connection with the respective poles, substantially
as described.
In witness whereof, I, the said Edward Thomas Hughes, have hereunto set
my hand and seal, this Tenth day of January, in the year of our Lord One
thousand sight hundred and seventy-eight