IMPROVEMENTS IN THE METHOD OF UTILISING ELECTRIC LIGHT FOR ILLUMINATING PURPOSES, AND IN APPARATUS FOR THE SAME
Year: 1874

page_text: LETTERS PATENT to: Charles Edward Powell, of Pope's Wood,
Binfield, in the County of Berks, Gentleman, for the Invention of
"IMPROVEMENTS IN THE METHOD OF UTILISING ELECTRIC LIGHT FOR
ILLUMINATING PURPOSES, AND IN APPARATUS FOR THE SAME."
Sealed the 1st June 1875, and dated the 24th December 1874.
PROVISIONAL SPECIFICATION left by the said Charles Edward Powell
at the Office of the Commissioners of Patents, with his Petition,
on the 24th December 1874.
I, CHARLES EDWARD POWELL, of Pope's Wood, Binfield, in the
3 County of Berks, Gentleman, do hereby declare the nature of the
said Invention for "IMPROVEMENTS IN THE METHOD OF UTILISING ELECTRIC
LIGHT FOR ILLUMINATING PURPOSES, AND IN APPARATUS FOR THE SAME," to be as
follows:-
The difficulties hitherto experienced in applying the electric light to
general uses have arisen, in the first place, from the impractibility of
having more than one electric lamp in one circuit, owing to the resistance
[Price Sd.]

page_text: offered by the air to the current of electricity between the carbon points,
and secondly, to the costliness of the present electric lamps, owing to
the delicate machinery required to keep the carbon points at a constant
distance apart.
Now my Invention has for its object the provision of an efficient and
economic method of utilising electric light for illuminating purposes by
incans of an electric lamp adapted to obviate the above-named
difficulties. For this purpose my Invention consists in the arrangement
and construction of a lamp in which the carbon points are placed in
vacuo, and with an automatic arrangement herein-after referred to for
closing the circuit if from fracture of the lamp or other cause the
vacuum cease. By this means the resistance of the atmosphere between
the carbon points and their consumption are reduced to a minimum.
Also the circuit is closed above the carbons in any one lamp in which
the vacuum may have ceased, so that other lamps in the same circuit
will not be affected thereby.

page_text: The core is a conical plug fitting the said conical aperture, such plug
being bored to receive a moveable plug capable of working up and down
but fitting the core air-tight, as also the core does the stock, but
insulated from it. The internal plug rests on the spring connecting the
poles.
The support varies in form according to the position in which the
lamp is placed or fitted, and is made in two parts insulated from cach
other, each having a suitable screw for connecting the wires from the
battery. One of the parts is in connection with the stock and the other
with the core.
The lamp is worked by exhausting the air in the globes or vessel, the
plug is depressed by the pressure of the atmosphere, thus pushing the
spring away from the pole, the current then instead of passing through
the spring passes between the carbon points. If the vacuum in the
lamp ceases from any cause, the plug will fly back and the poles be
reconnected by the spring. The resistance to the current between the
carbon points, which would affect other lamps in the same circuit, will
thus be avoided.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Charles Edward Powell in the Great Seal Patent
Office on the 24th June 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, CHARLES
EDWARD POWELL, of Pope's Wood, Binfield, in the County of Berks,
Gentleman, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-fourth day of December, in the
year of our Lord One thousand eight hundred and seventy-four, in the
thirty-eighth year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and graut unto me, the said Charles Edward Powell, Her
special licence that I, the said Charles Edward Powell, my executors,
administrators, and assigns, or such others as I, the said Charles Edward
Powell, my executors, administrators, and assigns, should at any time
agree with, and no others, from time to time and at all times thereafter

page_text: during the term therein expressed, should and lawfully might make,.
use, exercise, and vend, within the United Kingdom of Great Britain
and Ireland, the Channel Islands, and Isle of Man, an Invention for
"IMPROVEMENTS IN THE METHOD OF UTILIZING ELECTRIC LIGHT FOR ILLUMINATING
PURPOSES AND IN APPARATUS FOR THE SAME," upon the condition (amongst
others) that 1, the said Charles Edward Powell, my executors or admi-
nistrators, 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
10 be performed, and cause the same to be filed in the Great Seal,
Patent Office within six calendar months next and immediately after
the date of the said Letters l'atent.
NOW KNOW YE, that I, the said Charles Edward Powell, do hereby
declare the nature of my said Invention, and in what manner the
same is to be performed, to be particularly described and ascertained
in and by the following statement, reference being had to the Drawings
hereunto annexed, and to the letters and figures marked thereon (that is
to say) :-
My Invention of "Improvements in the Method of Utilizing Electric
Light for Illuminating Purposes, and in Apparatus for the same,"
consists in the means and apparatus, herein-after described, for obviating
the difficulties hitherto experienced herein,
The difficulties hitherto experienced in applying the electric light to
general uses have arisen, in the first place, from the impracticability of
having more than one electric lamp in one circuit owing to the
resistance offered by the air to the current of electricity between the
carbon points; and secondly, to the costliness of the present electric
lamps, owing to the delicate machinery required to keep the carbon points
at a constant distance apart.
means
of an
Now my Invention has for its object the provision of an efficient and
economic method of utilising electric light for illuminating purposes by
electric lamp adapted to obviate the above-named
difficulties. For this purpose my Invention consists in the arrangement
and construction of a lamp in which the carbon points are placed in
vacuo, and with an automatic arrangement, herein-after referred to, for
closing the circuit, if from fracture of the lamp or other cause the
the resistance of the atmosphere
vacuum
cease.
By this
means

page_text: between the carbon points and their consumption are reduced to a
minimum. Also the circuit is closed above the carbons in any one lamp
in which the vacuum may have ceased, so that other lamps in the same
circuit will not be affected thereby.
parent or semi-transparent material.
Secondly. The lamp proper composed of the parts for adjusting and
acting on the carbon points and producing the light.
And, Thirdly. The standard, or suspending, or mural support.
The air-tight globe or vessel is fixed to the stock by means of a clamp
or clamps.
The lamp proper is composed of three main parts, viz., the poles, the
stock, and the core. The poles are fastened to the stock, one of them
being insulated therefrom but connected with the core, and having a
spring fastened to it which presses against and forms a connection with
the other pole or the stock. The poles terminate in holders for the
carbon points, the holder of the pole in connection with the stock being
adjustable in the line of the axes of the carbon points. The stock has
an aperture (by preference conical) to receive the core, and is fitted with
a pneumatic tap by means of which the air in the interior of the lamp is
exhausted.
The core is a conical plug fitting the said conical aperture, such
plug being bored to receive a moveable plug capable of working up
and down, but fitting the core air-tight as also the core docs the stock,
but insulated from it. The internal plug rests on the spring connecting
the poles.
The support varies in form according to the position in which the
lamp is placed or fitted, and is made in two parts insulated from each
other, each having a suitable screw for connecting the wires from the
battery. One of the parts is in connection with the stock and the other
with the core.
The lamp is worked by exhausting the air in the globe or vessel, the
plug is depressed by the pressure of the atmosphere, thus pushing the
spring away from the pole; the current then instead of passing. through

page_text: '
glass disc (flat or otherwise, as occasion may require) fitting it air-
tight. The poles are insulated from the paraboloid, which is also a
reflecter internally. This form of lamp is adapted for railway signals
and other purposes in which a light is required to be directed on to a
particular spot or distance.
When in the semi-globular form the vessel is a half globe of glass
semi-transparent or otherwise, its rim fitting air-tight against the lamp,
the poles being so arranged 'as to meet as near the centre of the globe as
possible.
"
In Fig. 6 are represented two half globes, cach closing against the
side of the lamp, the poles being arranged to meet as near the centres
as possible. This form of lamp is adapted for rooms, magazines, streets,
compartiments of railway carriages and other uses.
"
When in the cylindrical form, as represented in Fig. 8, the air-tight
vessel is a cylinder of glass or other suitable material, according to the
purpose for which the lamp is required; the lamp in this case being in
two parts (cach closing one end of the cylinder) in the form of two discs
of metal or other suitable material.
The lamp proper, or apparatus for producing the light, consists of the
following elementary parts, which may be varied in shape in the various
kinds of lamp, while still retaining the principle of their mutual action.
c is a solid rock to which the poles are fitted, in which also are the
pneumatic exhaust tap d, the screw e by which the distance of the
carbon points is regulated, and an aperture / (by preference conical in
most instances) with the larger opening towards the exterior of the
lamp; g, g', are the poles, which are two pieces of brass, insulated from
each other but connected by a spring h fastened to one of them, termi-
nating in holders for the carbon or other suitable material used in
producing the light, one of them g being moveable in the line of the
axis of the carbons, worked from outside the lamp by the screw e or by
other suitable means. One of the poles g is in connection with the part
of the stock to which it is fastened.
The automatic arrangement for closing the circuit when necessary,
consists of two plugs, and, the outer plug / being of a conical shape
externally, fitting the aperture in the stock, so as to be air-tight, insu-
lated from it but in connection with the insulated plug g¹, aud an inner

page_text: cylindrical plug i working through the outer plug k, kept in position
(when the lamp is not working) by two strong springs, and pressing on
but not deflecting the spring that connects the poles.
The following are the arrangements for supporting and placing the
lamp in position -The stock of the lamp in every case has a projection
round the outer end of the conical plug with its exterior face worked to
form a screw m, which screw works into a corresponding one in the
holder, the shape of which holder may be varied to suit the position
which the lamp is intended to occupy, whether a perpendicular, or hori-
zontal, a standard, or hanging position.
In all cases the holder of the lamp is made in two parts, n and o
one inside the other, insulated from each other, a binding screw or
other method of fixing the wires from the battery being applied to
cacli.
The outer part, in which is the screw to receive the lamp, is connected
with the stock, and consequently with one of the poles y by means of
the screw m, the other part has a spring p passing some way into the
hollow screw and presses against the plug k, thereby securing contact
with it and consequently with the second pole g. This form of holder,
applicable to each form of lamp, is convenient, as in case of damage
to or any necessity arising for the removal of a lamp it can be
removed and another substituted without deranging the wires from the
battery.
The lamp is worked by exhausting the air in the globe or vessel by
means of the pneumatic exhaust tap d. The plug i is then depressed by
the pressure of the atmosphere, and the spring is pusbed away from the
pole g;
the electric current then instead of passing through the spring h
If the vacuum in the
passes between the carbon points y and g'.
lamp cease from any cause the plug will fly back and the poles will
be reconnected by the spring h.
The resistance to the current between
the carbon points, which would affect other lamps in the same circuit,
will thus be avoided.
Having thus described the nature of the said Invention and in what
manner the same is to be performed, I would remark that I do not
claim as of my Invention any of the parts represented or described
separately or otherwise than in combination for the purpose described;
but what I do claim as of my Invention is, the lamp composed of an

page_text: air-tight globe or vessel, the parts described for adjusting and acting
on the carbon points, for maintaining the currrent of electricity in
constant circuit, and for producing the light, and the standard or
suspending or mural support, whereby electric light is utilized for
illuminating purposes by placing the carbon points in vacuo and closing
the circuit of electricity by automatic means if the vacuum cease, as
herein-before described.
1) witness whereof, I, the said Charles Edward Powell, have
hereunto set my hand and seal, this Twenty-second day of
June, in the year of our Lord One thousand eight hundred and
seventy-five.
CHARLES EDWARD POWELL. (L.S.)
Witness,
WILLIAM SPENCE,
8, Quality Court,
Chancery Lanc.