Improvements in or connected with Electric Arc Lighting.
Year: 1899

page_text: PROVISIONAL SPECIFICATION.
Improvements in or connected with Electric Arc Lighting.
I, ALEXANDER VOSMAER, of 49, Zylweg, Haarlem, in the Kingdom of Holland,
Engineer, do hereby declare the nature of this invention to be as follows:-
My invention relates to a novel arrangement in electric are lighting, whereby
neither a regulating arrangement nor auxiliary resistance is required and the
carbons which have been hitherto indispensable are entirely dispensed with and,
consequently, the cost of the apparatus as well as of its maintenance is reduced
to a minimum.
My invention consists essentially in the employment of two fixed electrodes
arranged opposite one another a few millimetres apart, according to the length
of arc to be obtained, and in causing them to be traversed by a current of
relatively high tension and very low intensity so that the arc is created between
the electrodes and can be maintained without any apparent or appreciable waste
or consumption of the electrodes, the ends, or one end only of which, according to
circumstances, attain or attains a degree of white heat constituting the source
of light.
In experimenting with my invention my observations respecting the choice
of electrodes have principally been directed to the employment of metallic
electrodes susceptible of being covered, under the action of the current, with a
layer of oxide which prevents the fusion of the electrode at the part where it
is brought to incandescence under the action of the heat developed by the arc.
With this idea I preferably make use of electrodes of pure nickel or of nickel
alloys, and it seems that, in this case, it is probably to the formation of a layer
of oxide of nickel at the end of each of the electrodes that the possibility must
be attributed of obtaining an are between the two electrodes without any appreci-
able consumption of the latter.
One of the essential conditions for the practical carrying out of my invention
consists in the relation which should exist between the intensity of the current
to be employed and the diameter of the electrodes, so as to prevent the fusion of
the said electrodes..
I have found that an alternating current of one tenth of an ampère with a
tension of 400 to 500 volts allows of obtaining a source of light of about 50 candle
power with electrodes of about millimetres in diameter in which it was im-
possible to detect the least waste even after having been in use for a considerable
number of hours.
In the practical example hereinbefore referred to, by using two electrodes of
the same nature, nickel for example, I obtain two luminous or light emitting
surfaces, one at the end of each electrode; nevertheless, a single surface can be
obtained by substituting for one of the electrodes, a metal electrode which will
not emit light such, for example, as copper. This would especially be suitable
for producing a light for searchlight apparatus.
Another practical form of my invention consists in the employment of combined

page_text: electrodes comprising, for example, a metal tube having an inner core of an
alkaline earthy substance, or of a suitable rare earth, or of other incombustible
and refractory chemical substance or composition.
With this kind of electrode the metal tube serves to increase the conductibility
of the electrode in order to thus create the arc whilst the interior core allows of
obtaining at the end of the electrode a surface emitting a light of the greatest
intensity.
The lamp, thus constructed, therefore consists of two fixed electrodes suitably
arranged and insulated from one another. Its extraordinary simplicity will
therefore be readily perceived. The source of light can, obviously, be surrounded
if desired with a suitable diffusing globe; this globe, nevertheless, is not necessary
as the arc can be perfectly maintained in free air.
Deted the 1st day of November 1899
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, 'Agents for the Applicant.
I, ALEXANDER VOSMAER, of 49, Zylweg, Haarlem, in the Kingdom of Holland,
Engineer, do hereby declare the nature of this invention and in what manner
the same is to be performed to be particularly described and ascertained in and
by the following statement:-
My invention relates to a novel arrangement in electric arc lighting, whereby
neither a regulating arrangement nor auxiliary resistance is required and the
carbons which have been hitherto indispensable are entirely dispensed with and,
consequently, the cost of the apparatus as well as of its maintenance is reduced
to a minimum.
My invention consists essentially in the employment of two fixed electrodes
arranged opposite one another a few millimetres apart, according to the length
of arc to be obtained, and in causing them to be traversed by a current of
relatively high tension and very low intensity so that the arc is created between
the electrodes and can be maintained without any apparent or appreciable waste
or consumption of the electrodes, the ends, or one end only of which, according to
circumstances, attain or attains a degree of white heat constituting the source
of light.
I have found electrodes of pure nickel or of nickel alloys to give good results,
the consumption of such electrodes when the arc is formed being inappreciable
which is probably due to the formation of a layer of oxide of nickel at their ends.
One of the essential conditions for the practical carrying out of my invention
consists in the relation which should exist between the intensity of the current
to be employed and the diameter of the electrodes, so as to prevent the fusion of
the said electrodes.
I have found that an alternating current of one tenth of an ampère with a
tension of 400 to 500 volts allows of obtaining a source of light of about 50 candle
power with electrodes of about 3 millimetres in diameter in which it was im-
possible to detect the least waste even after they had been in use for a consider-
able number of hours.
By using two electrodes of the same nature, nickel for example. I obtain two
luminous or light emitting surfaces, one at the end of each electrode; neverthe-
less, a single surface can be obtained by substituting for one of the electrodes, a

page_text: metal electrode which will not emit light, such, for example, as copper. This
would especially be suitable for producing a light for searchlight apparatus.
The lamp, thus constructed, therefore consists of two fixed electrodes suitably
arranged and insulated from one another. Its simplicity will be readily per-
ceived. The source of light can, obviously, be surrounded if desired with a
suitable diffusing globe; this globe, nevertheless, is not necessary as the are
can be perfectly maintained in free air.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is:-
1. In an electric arc lamp the employment of fixed electrodes one or both of
which is or are made of nickel or nickel alloy and traversed by a current of high
tension and low intensity to produce at the end of one of the electrodes (or of
both of them as the case may be) a light emitting surface consisting of a layer of
nickel oxide, substantially as hereinbefore described.
2. An electric are lamp consisting of the parts combined, arranged and operat-
ing, substantially as herein before described.
Dated the 1st day of August 1900
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.