IMPROVEMENTS IN OBTAINING LIGHT BY ELECTRICITY
Year: 1858

page_text: LETTERS PATENT to Charles Weightman Harrison, of Woolwich, in the
County of Kent, Civil Engineer, for the Invention of "IMPROVEMENTS IN
OBTAINING LIGHT BY ELECTRICITY."
Sealed the 16th November 1858, and dated the 17th May 1858.
PROVISIONAL SPECIFICATION left by the said Charles Weightman
Harrison at the Office of the Commissioners of Patents, with his
Petition, on the 17th May 1858.
I, CHARLES WEIGHTMAN HARRISON, of Woolwich, in the County of Kent,
Civil Engineer, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN OBTAINING LIGHT BY ELECTRICITY," to be as follows:-
This Invention relates to the use of mercury, or other fluid or semi-fluid
body, as one or more of the electrodes in obtaining light by electricity, and
my improvements herein comprise,―
First, the employment within the lamp of a burner or tube formed of a
suitable material in any convenient shape or dimensions, and in feeding it by
means of fitting arrangements with a supply of the fluid electrode, so that it
shall remain full or nearly so during waste or consumption by the light.
Second, in controlling or regulating the supply of fluid electrodes by means
of a tap, or other like agent, worked by electric action.
Third, in forming a fluid positive compound electrede by dividing the
steam, so that a number of separate lights may be produced from it in place of

page_text: one light as heretofore. By this means the magnitude of the centre or focus
of light may be increased to any desired extent.
Fourth, in maintaining by self-acting means a constant degree of separation
between the point where the stream of one electrode breaks, and the reservoir
of a second electrode into which the stream falls or forms contact. I accom-
plish this by connecting or suspending the reservoir of the second clectrode to
a float which is placed on the first electrode contained in another reservoir from
whence the stream issues, whereby as the float descends the second reservoir is
advanced in exact proportion to the length which the stream is diminished by
reduced pressure; I also effect the same object by causing by any suitable
arrangement the waste or condensed mercury, or other fluid forming a
descending stream electrode, to elevate the lower electrode or reservoir; this
may be conveniently done by placing it on a float, under which such wasto
fluid is allowed to collect.
Fifth, in forming the reservoirs for holding fluid electrodes of a combination
of lamp black, or other form of carbon and silica, or of lamp black and china
clay, rottenstone, or other highly infusible material.
Sixth, in preventing the condensation of vapors upon the glass or case of
electric lamps, by means of a stream of water, or other liquid or air, being
made by any convenient arrangement to flow over or upon the interior surfaco
of the glass or case. Also by partly or wholly filling the glass or case with
water, alcohol, bisulphuret of carbon, or other suitable liquid, and in causing it
to circulate around the light, or to pass away through apparatus by which it
may be filtered, and then returned to the lamp again by a pump or other
means, which may be worked by electric action.
And, seventh, in preventing the rise of vapors from the waste fluid of elec-
trodes, by the introduction of a stratum of water or other liquid into the wasto
pipe or reservoir.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Charles Weightman Ilarrison in the Great Seal Patent Office 30
on the 17th November 1858.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, CHARLES
WEIGHTMAN HARRISON, of Woolwich, in the County of Kent, Civil Engineer,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters 3
Patent, bearing date the Seventeenth day of May, in the year of our Lord

page_text: One thousand eight hundred and fifty-eight, in the twenty-first year of ler
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said Charles Weightman Harrison, Her special licence that I, the said Charles
Weightman Harrison, my executors, administrators, and assigns, or such
others as I, the said Charles Weightman Harrison, my executors, adminis-
trators, and assigns, should at any time agree with, and no others, from time
to time and at all times thereafter during the term therein expressed, should
and lawfully might make, use, exercise, and vend, within the United King-
dom of Great Britain and Ireland, the Channel Islands, and Isle of Man, an
Invention for IMPROVEMENTS IN OBTAINING LIGHT BY ELECTRICITY," upon the
condition (amongst others) that I, the said Charles Weightman Harrison, my
executors or administrators, by an instrument in writing under my, or their,
or one of their hands and scals, should particularly describe and ascertain
the nature of the said Invention, and in what manner the same was to be
performed, and cause the same to be filed in the Great Seal Patent Offico
within six calendar months next and immediately after the date of the said
Letters Patent.
NOW KNOW YE, that I, the said Charles Weightman Harrison, do hereby
declare the nature of my said Invention, and in what manner the samo
is to be performed, to be particularly described and ascertained in and by
the following statement thereof, reference being had to the Drawings hiereunto
annexed, that is to say:-
This Invention relates to the use of mercury, or other fluid or semi-fluid
body, as one or more of the electrodes in obtaining light by electricity, and my
improvements herein comprise,-
First, the employment within the lamp of a burner or tube formed of a
suitable material, in any convenient shape or dimensions, and in feeding it by
means of fitting arrangements with a supply of the fluid electrode, so that it
shall remain full or nearly so during waste or consumption by the light.
Second, in controlling or regulating the supply of fluid electrodes by means
of a tap or other like agent, worked by electric action.
Third, in forming a fluid positive compound electrode by dividing the stream
so that a number of separate lights may be produced from it, in place of one
light as heretofore. By this means the magnitude of the centre or focus of
light may be increased to any desired extent.
Fourth, in maintaining by self-acting means a constant degree of separation
between the point where the stream of one electrode breaks, and the reservoir
of a second electrode, into which the stream falls or forms contact. I accom-
plish this by connecting or suspending the reservoir of the second electrode to

page_text: a float, which is placed on the first electrode contained in another reservoir,
from whence the stream issues, whereby as the float descends, the second
reservoir is advanced in exact proportion to the length which the stream is
diminished by reduced pressure; I also effect the same object by causing
by any suitable arrangement tho waste or condensed mercury, or other
fluid forming a descending stream electrode, to elevate the lower electrode or
reservoir; this may be conveniently done by placing it on a float, under which
such waste fluid is allowed to collect.
Fifth, in forming the reservoirs for holding fluid electrodes of a combination
of lamp black, or other form of carbon and silica, or of lamp black and china
clay, rottenstone, or other highly infusible material.
Sixth, in preventing the condensation of vapors upon the glass or case of
electric lamps, by means of a stream of water, or other liquid or air, being
made by any convenient arrangement to flow over or upon the interior surface
of the glass or case, also by partly or wholly filling the glass or case with
water, alcohol, bisulphuret of carbon, or other suitable liquid, and in causing
it to circulate around the light, or to pass away through apparatus, by which it
may be filtered, and then returned to the lamp again by a pump or other
means, which may be worked by electric action.
And, seventh, in preventing the rise of vapors from the waste fluid of
electrodes by the introduction of a stratum of water or other liquid into the
waste pipe or reservoir.
And in order that my said Invention may be fully understood, I now
proceed to describe and refer to the several Figures on the Sheets of Drawings
hereunto annexed.
Figure 1, a side elevation, with the lamp in section; and Figure 2, a back
elevation, with the door removed, of an electric lamp, constructed with a tube
or burner, as herein first described. a is the tube or burner; b, the reservoir
containing a supply of mercury or other fluid electrode, which on turning the
tap c, flows through the pipe in a stream into the cup e; this cup is placed
slightly higher than the mouth of the burner, with which it is connected by
the pipef, by which it is kept full. The second fluid electrode is contained in
the reservoir g, from which it passes on turning the connected tap to a jet i,
screwed in the top of the lamp; from this jet it descends in a fine stream
upon the other clectrode in the burner, and thus completes the circuit of the
electric current within the lamp. The distance between the burner and the
jet when a fine stream of mercury is used should be about two inches, and the
height of the reservoir connected to the jet from 16 to 18 inches above the
top of the lamp. If the electricity employed be of moderate power, as that

page_text: yielded by a Grove's battery, of from 12 to 18 ordinary cells, then it is neces-
sary to fix the distance between the jet and burner to that point of the stream
where it is about to break into drops, but with a more powerful current, such
as that derived from a like battery of 36 or more cells; then this is not a
matter of importance, as the light will be produced immediately the stream
reaches the burner. When the stream is made an electrode of positive
electricity (the invariable practice hitherto), it is extremely difficult to produce a
steady light, the varying resisitance causing the light to run up and down. Now,
I have found that when the stream is rendered negative, the light is much
more steady and uniform; I therefore connect the binding screws N and I'
with the battery, so that the mercury in the burner shall be positive and the
stream negative. j, reservoir into which the waste or condensed electrode is
conducted by the pipe & from the lamp; 1, reflector regulated by the screw m;
n, glass tube surrounding the light as closely as possible, without danger of
fusion, as shown in the Drawing of an improved mecurial lamp annexed to
the Specification of a former Patent granted to me, and dated the 28th day of
February 1857. I prefer to have this glass of a pale orange red hue, in order
to neutralize the blue tint of the mercurial light. To avoid amalgamation the
frames or caps of the lamp o, o, in which the glass is cemented, as well as the
pipes and reservoirs, are made of iron. I prevent the rise of vapors within
the waste reservoir by first pouring therein a stratum of oil or water.
In Figure 3 is shown an arrangement by means of which the supply of
fluid electrodes is controlled by the passing electric current. a, electro-magnet,
which, on completion of the electric circuit, attracts the keeper fixed on the
antagonistic spring b, and shuts the valve or tap c, cutting off the flow through
the pipe d, d, which connects the reservoir to the lamp. On the exhaustion of
the fluid clectrode in the lamp the keeper is released and the valve opened,
thus admitting a fresh supply; e, screw by which the extent of motion in the
spring is regulated.
I produce any required number of lights by dividing the flowing electrodes
when they arrive within the lamp into separate jets and burners connecting
them in the manner as herein described in reference to Figure 1. These may
be conveniently placed in a circle, one scries over the other, and in place of
burners a ring or hollow cylinder of carbon may be made to rotate on a vertical
support by clockwork, the streams from the jets descending upon its edge
produce the lights. Each series of lights is connected by one common con-
ductor to its pole of the battery.
Figure 4 represents a vertical section of another of my improved lamps, in
which the waste or condensed mercury of a stream electrode is made to elevate

page_text: the lower electrode, and thereby to maintain a constant degree of separation
between them. a is a cylindrical reservoir, forming the base of the lamp;
c, float carrying the tube d, in which is placed the carbon pencil electrode e;
f, cover screwed on the reservoir. In the centre of this cover an aperture is
made through which the carbon pencil is allowed freely to pass, and on cach
side of the aperture the tubes b, b, are fixed; these serve both as a guide to
the float and to conduct the waste mercury into the reservoir; g, pale orange
red tinted glass tube, of about two inches in diameter, cemented at the upper
end in the iron cap h, and at the lower end in the ring i, the latter screwing
on the cover f; j, jet cemented in the metal socket k, which screws in the
cap 1, pipo leading to the supply reservoir, and connected to the cap h
by screwing down the piece m. The jet is formed with a minute capillary
aperture, through which the mercury flows in a fine stream upon the end of
the carbon pencil, and the diameter of this electrode, which I prefer to use, is
ths of an inch. The interior diameter of the cylindrical reservoir which I
have found best adapted to these electrodes is 6 inches, the battery power
being 36 of Grove's cells, with negative plates 3 inches by 6 inches.
The most infusible material of which to form the jets and burners I have
found to be a combination of equal portions of lamp black or finely divided
graphite, and precipitated silica or washed china clay. These, when well
mixed together, are pressed in suitable moulds, and then burnt at a high
temperature in a close retort.
In another of my improved lamps I prevent the condensation of mercurial
or other vapors upon the glass, which incloses the light by means of arrange-
ments similar in principle to those represented in Figure 5. a jet, and b burner,
connected respectively by the tubes c, d, with supply reservoirs; e, tube
connected with a reservoir of distilled water or other suitable liquid, or con-
densed air or oxygen gas, and terminating in a hollow ring f fixed in the top
of the lamp; the outside of this ring is perforated with a number of small
holes through which the water escapes and flows over the interior surface of
the glass . I prefer to use water for this purpose, as I find that the small
amount of aqueous vapor which is generated, has the effect of neutralizing
the blue tint of the mecurial light without sensibly impairing its brilliancy.
h, waste pipe by which the water and condensed mercury are carried off to a
suitable reservoir.
Another of my improvements in this part of my Invention consists in filling
the glass which incloses the light with some refractive liquid, such as those
named in describing this part of my Invention in my Provisional Specification;
but I have since found that pure castor oil or oil of turpentine may be

page_text: employed with greater advantage for this purpose. I cause a constant clown-
ward current of the liquid to flow within the glass, by means of a suitable
connecting pipe from an upper reservoir, and then to pass away to a lower
reservoir, carrying with it the condensed mecurial vapors. The liquid is then
filtered and returned again by any convenient means to the upper reservoir.
In this lamp I prefer to use as the electrodes a jet or stream in combination
with a tube or burner, in the manner herein-before described.
And having now described the nature of my said Invention, and in what
manner the same may be performed, I declare that I claim,-
First, the construction and employment within the lamp of a burner, in the
manner and for the purpose herein-before described.
Second, the self-regulating meaus described herein for controlling the supply
of fluid electrodes.
Third, the mode herein-before described of increasing the magnitude of the
centre or focus of light.
Fourth, the construction and employment of a float in combination with a
stream electrode, as herein-before described.
Fifth, the construction and use of jets, burners, or reservoirs formed of
carbon mixed with silica, or other highly infusible material, as herein
described.
Sixth, the methods herein described of preventing the condensation of
vapors upon the glass.
And, seventh, the introduction of a stratum of water or other liquid into the
waste pipe or reservoir.
In witness whereof, I, the said Charles Weightman Harrison, have
hereunto set my hand and seal, this Seventeenth day of November,
One thousand eight hundred and fifty-eight.
CHAS. W. IIARRISON. (L.S.)