IMPROVEMENTS IN APPARATUS FOR PRODUCING, MAINTAINING, AND SUBDIVIDING ELECTRIC LIGHT
Year: 1878

page_text: LETTERS PATENT to Frederick Herbert William Higgins, of 17, Cornhill, in the
City of London, for the Invention of "IMPROVEMENTS IN APPARATUS FOR
PRODUCING, MAINTAINING, AND SUBDIVIDING ELECTRIC LIGHT."
"
PROVISIONAL SPECIFICATION left by the said Frederick Herbert William
Higgins at the Office of the Commissioners of Patents on the 4th November
1878.
FREDERICK HERBERT WILLIAM HIGGINS, of 17, Cornhill, in the City of London.
IMPROVEMENTS IN APPARATUS FOR PRODUCING, MAINTAINING, AND SUBDIVIDING
ELECTRIC LIGHT."
This Invention has for its object improvements in apparatus for producing,
maintaining, and subdividing electric light.
For this purpose I employ a long, narrow, inetallic cylinder containing mercury.
Carbon sticks, varying in thickness and number, according to the volume of light
required, are placed loosely in tubes open at one end, and slit longitudinally some-
thing like a sliding taper holder. These tubes are immersed in the column of
mercury with only the open end projecting above its surface. The mercury enters
by the longitudinal slit and forces the carbon upward until it infringes upon a
plate of somewhat highly resistant carbon. The current is then caused to flow from
the vessel containing the mercury, through the exposed stick of carbon to the carbon
plate;
the carbon becomes incandescent throughout, but chiefly at the point of
junction with the plate, where it gradually burns away.
The loss is compensated for by the carbon rod being constantly propelled upward
from below. Several carbons may if necessary be immersed in the same vessel of
mercury, and there may be several in the same circuit, either in series or in mul-
tiple arc. To prevent extinction of other lights in the circuit during a momentary

page_text: interruption in one lamp, I employ a contact maker to complete the circuit when
the current fails to flow through the carbon. This circuit is completed through a
resistance equal to a little more than that of the-lamp-and-the-electro-magnet.
By-this-means-the-lamp is able to relight itself, or the alternative resistance may
consist of another carbon."
The object of the loose-fitting tube which encloses the carbon pencil is to serve as
-a-guide-and at the same time facilitate the renewal or immersion of fresh carbon.
Contact with the carbon pencil is made through the mercury. The nozzle from
which the carbon pencil. emerges-may be formed from a substantial piece of copper,
to absorb the heat and thus chill the lower part of the carbon pencil.
To increase the buoyancy of the carbon a float may be.attached-to-its lower end.
Where it may-be-necessary to extinguish some of the lights in a circuit it may be
done by the employment of automatic switches in the lamps in question, and a
reversal of the current.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Frederick Herbert William Higgins in the Great Seal Patent
Office on the 2nd May 1879.
FREDERICK HERBERT WILLIAM HIGGINS, of 17, Cornhill, in the City of London.
"IMPROVEMENTS IN APPARATUS FOR PRODUCING, MAINTAINING, AND SUBDIVIDING
ELECTRIC LIGHT."
My improvements relate to that class of electric lamps in which a stick or sticks
of carbon pressed endwise up to and against another carbon electrode are rendered
incandescent by an electric current passed through them.
According to my Invention I immerse the lower end of the stick or sticks of
carbon in a column of mercury, or it might be other liquid, and employ the mercury
not only as a means of pressing the stick or sticks continuously upwards but also
for transmitting an electric current directly to them.
In the Drawings hereunto annexed I have shown vertical sections of two lamps
constructed according to my Invention. In each of these lamps a single stick only
of carbon is pressed upwards against the upper carbon, but, if desired, the lamps
might be constructed so that two or more sticks might be similarly pressed upwards
against it.
In these lamps A is an iron tube containing the column of mercury; B is an
enlarged chamber at the top of the tube A; this chamber is also partly filled with
the mercury, and being of comparatively large diameter the level of the mercury in
it will not greatly vary whether a long or a short length of carbon stick is iminersed
in the mercury. C is a cover fixed over the top of the chamber B; at its centre it
carries a block of copper D, which has a hole formed vertically through it. E is
the carbon stick, which passes through the hole in the block D and into the mer-
cury in the tube A.; the carbon stick also passes through a fixed tubular guide A¹
near the upper part of the tube A. F is a block of asbestos or other slow conductor
of heat on the top of the cover C. G is a metallic reflector resting on the top of
the chamber B. H, H, are radial plates of copper affixed to the exterior of the
upper part of the tube A. These plates or wings serve to pass away heat from the
tube A to the surrounding air. I is a tubular metallic stand for holding the tube A.
It carries at its top a block J of ebonite or other non-conducting material. The
tube A passes down through a hole in this block and also through another block K
of similar material at the lower part of the stand. The wings H rest on the top of
the upper block J. L, L, are air holes through the lower part of the tubular
stand, and M, M, are other air holes through the block J. As the tube A becomes
warmed, a current of air rises up through the tubular stand, and passing out
through the air holes in the upper block J escapes between the radial wings or
blades H, and so conveys away heat from them and from the tube A.
N is the upper carbon; it is, by preference, electro-plated externally with copper,
to facilitate the making of good electric contact with it. In the lamp shewn at
Figure 1, the upper carbon is carried at the lower end of a copper tube O supported
by a bent tubular stem P which is held in a clamp on the exterior of the upper part
of the stand I.
As the copper tube O becomes heated, air passes up into it through the hollow
stem P and escapes from it through its open top. The tube O is by this means
kept from being overheated. Qis a glass globe resting on a disc carried by tho
tube A, as shewn. Holes are formed in the disc to allow air to rise up through the
globe. Or, in some cases, a closed globe might be used'; the globe might then fit
around and be supported by the reflector, so that the interior of the reflector might
be left exposed to the air for the purpose of keeping it cool.
When the lamp is in use the stick of carbon E is put in connection with one
pole of a battery or other producer of electricity through the mercury bath and
tube A, whilst the upper carbon N is put in connection with the other pole through

page_text: -
the metallic tube O and stand I. The copper nozzle D through which the upper
end of the carbon stick E passes serves to keep the stick E cool below the exposed_
end, which becomes incandescent. When it is required to insert a fresh stick of
carbon into the tube A, the glass globe Q is taken off and the upper carbon M is
turned on one side the stem-P, turning in its socket to allow of its being so moved.
The remaining portion of the old stick of carbon is then taken away and a fresh
carbon stick is put in-its plaec, and pressed and held down into the bath of mercury
in the tube A. The upper carbon is then turned back into its place, and the
-pointed-end-of-the-carbon stick allowed to bear against it.
The lamp shown at Figure 2 differs from the lamp shown in Figure 1 in that the
copper nozzle D is itself made to form the cover-of-the-chamber B and also to form
the upper portion of the reflector, and also in that provision is made for lowering
the upper carbon as it slowly consumes away. The arrangement for effecting this
is clearly shown in the Drawing. Any other suitable mechanical contrivance may
however be used. The means provided in the lamp shewn at Figure 1 for keeping
cool the copper tube O which carries the upper carbon are not shown as being used
in the lamp shewn at Figure 2. Similar means may however be adopted. The
curved stem which carries the tube may be made hollow and admit air to the
bottom of a cylindrical and open topped casing surrounding the tube O. Other
contrivances than those shown can also be adopted for keeping cool the several
parts of the lamp.
The lamps may be used singly and worked with a current derived from a battery
or other source. Or several electric lamps constructed as above described may be
placed in the same circuit in continuous series. In this case, to prevent extinction
of other lights in the circuit during a momentary interruption in one lamp, a
contact maker may be employed to complete the circuit when the current fails to
flow through the carbons, as will readily be understood. Or a number of such
lainps may be placed in separate branch circuits from a single main conductor.
Having thus described the nature of my Invention, and the manner of performing
the same, I would have it understood that I claim as my improvements in
apparatus for producing, maintaining, and subdividing electric light,
First. The immersion of one electrode, preferably a stick or pencil of carbon, in a
bath of mercury or other liquid of greater specific gravity than the electrode, so as
to maintain the one electrode in constant contact with the other electrode by
flotation, and also to convey a current of electricity directly to the electrode by
means of the mercury or other liquid.
Second. The construction of electric lamps substantially as herein before described,
and shewn in the Drawings annexed.
In witness whereof, I, the said Frederick Herbert William Higgins, have here-
unto set my hand and seal, this Second day of May, in the year of our
Lord One thousand eight hundred and seventy-nine.
F. H. W. HIGGINS. (L.S.)