Improvements in or connected with Means or Apparatus for Producing Radiation by Electricity.
Year: 1896

page_text: Date of Application, 24th Sept., 1896
Complete Specification Left, 23rd June, 1897-Accepted, 24th July, 1897
PROVISIONAL SPECIFICATION.
Improvements in or connected with Means or Apparatus for
Producing Radiation by Electricity.
We, CHARLES HENRY STEARN, Electrician and CHARLES FREDERICK TOPHAM,
Engineer both of 47 Victoria Street in the City of Westminster, do hereby declare
the nature of this Invention to be as follows:--
If an electric current of high potential be passed through a vessel exhausted of
air, or other gas, and between electrodes suitably shaped, one or both being concave,
a solid body placed at, or near, the centre of curvature of the cathode, becomes
incandescent at a certain stage of exhaustion, or attenuation of the air, or gas,
and at a higher degree of vacuum, or attenuation of the air or gas in the said
vessel, the said solid body becomes phosphorescent, to a greater or lesser degree,
according to the nature of the solid body employed. At a still higher vacuum
or attenuation of the said air, or gas, certain substances emit, or direct, the rays
known as Röntgen, or rays. Permanent effects of radiation in the required
manner have not hitherto been attainable, however, on account of the speedy rise
in the degree of vacuum, or attenuation of the air, or gas, in the said vessel owing
to the absorption of the air, or gas present.
The object of our Invention is to overcome this objection by providing means
whereby the condition of the vacuum, or attenuation of the air, or gas, in the said
vessel is rendered constant, or practically constant. This we effect by combining
with the electric circuit a device such that on the vacuum becoming, or tending
to become too high to fulfil the required conditions the alteration in the electric
conditions in the said circuit cause the necessary small traces of air, or other gas,
to lower the vacuum to the required degree, or maintain it normal to be supplied
to the said vessel.
This is conveniently effected by placing in communication with the said
vessel a substance which when an electric spark is passed through it will evolve
the necessary small traces of air, or other gas, to make up deficiency, this sparking
being caused only when the resistance through the vessel increases, owing to the
rise in the degree of vacuum, to such a point as to cause current to pass through
a bye-pass, or shunt, so as to produce the sparking.
The following is a suitable arrangement for the purpose, although we do not
limit ourselves to the precise details. We attach to, or form with, the vessel in
which the vacuum is created (we will refer to this as the main vessel) and which
contains the cathode, or cathodes, and interceptor, or solid body, as aforesaid,
an extension, or communicating chamber, containing a material which, under
the action of an electric spark, will evolve small traces of air, or other gas. The
terminals, or electrodes, between which the sparking is effected are fused in the
walls of the said communicating chamber and this device is connected in series
with a resistance, such as a vacuum tube, with the electrodes similarly fused in
its walls, this vacuum tube being exhausted to a slightly higher degree than that
to be maintained in the main vessel. The wires, which are so connected with the

page_text: said communicating chamber and the said vacuum tube, are connected as a bye-
pass, or shunt, past the main vessel. So long as the vacuum in, and consequently
the current through, the main vessel remains normal the devices in the shunt,
or bye-pass, are inoperative; but as soon as the vacuum becomes too high, so that
the resistance through the main vessel becomes abnormal, the current passes by
the shunt, or bye-pass, and sparking occurs in the aforesaid communicating
chamber, so that, from the substance therein, a small trace of air, or other gas,
is evolved, which restores the vacuum in the main vessel to its normal condition.
By regulating the resistance in the shunt, or bye-pass, the degree of vacuum in
the main vessel can be maintained at any desired point.
Other resistance than the vacuum tube can be used, or we may use other means
for allowing current to pass to create the sparking at the requisite time:
for example, we may use a galvanometer, or equivalent device, in the primary,
or secondary, circuit of a transformer, which, by the reaction produced by the fall-
ing off of current due to the rise of vacuum in the main vessel, causes the
galvanometer, or equivalent device, to complete the circuit and send a current
through the sparking device.
Hitherto only carbon, platinum, or similar bodies, which are unstable, or only
emit light, at very high temperatures, have been used at the focus of cathode rays,
and consequently the luminous effects have been weak. We can obtain a very
high degree of incandescence with but comparatively small expenditure of electric
energy by employing materials which emit light at lower temperatures than do
the bodies hitherto used. Suitable substances for our purpose are the rare earths,
such as used for the Welsback incandescent gas lamps, or other refractory
oxides.
Instead of using a single concave cathode in the main vessel, and direct currents,
with an induction coil and contact breaker, much more powerful light effects
can be obtained, without disintegration of the refractory material, by employing
an alternating current from a transformer and making both electrodes concave,
when the refractory material will be rendered luminous on both sides, and the
light will be found to be absolutely steady.
Dated this 24th day of Sontember 180
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, London, W.C., Agents.
Improvements in or connected with Means or Apparatus for
Producing Radiation by Electricity.
We, CHARLES HENRY STEARN, Electrician, and CHARLES FREDERICK TOPHAM,
Engineer, both of 47 Victoria Strect, in the City of Westminster, 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:
-
If an electric current of high potential be passed through a vessel exhausted of
air, or other gas, and between electrodes suitably shaped, one or both being concave,
a solid body placed at, or near, the centre of curvature of the cathode, becomes
incandescent at a certain stage of exhaustion, or attenuation, of the air, or gas,
and at a higher degree of vacuum, or attenuation of the air or gas in the said
vessel, the said solid body becomes phosphorescent, to a greater, or lesser, degree,
according to the nature of the solid body employed. At a still higher vacuum
or attenuation, of the said air, or gas, certain substances emit, or direct, the rays
known as Röntgen, or a rays. Permanent effects of radiation in the required

page_text: manner have not hitherto been attainable, however, on account of the speedy rise
in the degree of vacuum, or attenuation of the air or gas, in the said vessel owing
to the absorption of the air, or gas, present.
The object of our invention is to overcome this objection by providing means
whereby the condition of the vacuum, or attenuation of the air, or gas, in the said
vessel, is rendered constant, or practically constant. This we effect by combining
with the electric circuit a device such that on the vacuum becoming, or tending
to become too high to fulfil the required conditions the alteration in the electric
conditions in the said circuit cause the necessary small traces of, air, or other gas,
to lower the vacuum to the required degree, or maintain it normal to be supplied
to the said vessel.
This is conveniently effected by placing in communication with the said
vessel a substance which, when an electric spark is passed through it, will evolve
the necessary small traces of air, or other gas to make up deficiency, this sparking
being caused only when the resistance through the vessel increases, owing to the
rise in the degree of vacuum to such a point as to cause current to pass through
a bye-pass, or shunt so as to produce the sparking.
The following is a suitable arrangement for the purpose although we do not
limit ourselves to the precise details. The accompanying diagram will serve to
assist the description. We attach to, or form with, the vessel A in which the
vacuum is created (we will refer to this authe main vessel) and which contains the
cathode, or cathodes a and 7 and interceptor, or solid body e as aforesaid, an extension
or communicating chamber d containing a material which, under the action of an
electric spark will evolve small traces or air, or other gas. This material will be of a
nature in accordance with the gas which it is desired to liberate. Chlorate of
potash or an ammonium salt are for instance suitable for the purpose. The
terminals or electrodes between which the sparking is effected are in a shunt
circuit from the principal circuit and the said terminals are fused in the walls
of the said communicating chamber and in this shunt circuit is any suitable
resistance e such that the total resistance in the shunt circuit is slightly greater
than that to be maintained in the vessel A. So long as the vacuum in, and
consequently the electric current through, the main vessel A remains normal the
devices in the shunt, or bye-pass, are inoperative, but as soon as the vacuum becomes
too high, so that the resistance through the main vessel A becomes abnormal,
the current passes by the shunt, or live-pass and sparking occurs in the aforesaid
communicating chamber d, so that, from the substance therein, a small trace of
air, or other gas, is evolved, which restores the vacuum in the main vessel to its
normal condition. By regulating the resistance in the shunt, or bye-pass, the
degree of vacuum in the main vessel A can he maintained at any desired point.
Other means may he employed for allowing current to pass to create the
sparking at the requisite time; for example, we may use a galvanometer, or
equivalent device, in the primary, or secondary, circuit of a transformer, which,
by the reaction produced by the falling off of current due to the rise of vacuum
in the main vessel, causes the galvanometer, or equivalent device, to complete the
circuit and send a current through the sparking device.
The luminous effects hitherto obtained from the incandescence of solid bodies
under the influence of cathode rays have been too weak and fluctuating for applica-
tion to practical purposes. We obtain a very high-degree of incandescence with
comparatively small expenditure of electric energy by employing for the anti-
cathode, materials 'which can be rendered incandescent such as refractory oxide
of thorium or other refractory oxides or earths similar for example to those used
for the Duer von Welsbach incandescent gas lamps, either in the form of com-
pressed dises or preferably of several thicknesses of the spongy material which
results from immersing carbonisable fabrics in solutions of the rare earths or other
refractory oxides and afterwards hurning out the organic matter.
We may use a single concave cathode in the main vessel, and direct currents, with
an induction coil and contact breaker but inuch more powerful light effects can

page_text: be obtained by employing an alternating current from a transformer as the source.
of electric energy and placing the anti-cathode between two curved or concave
aluminium electrodes each of which under the reversals of the electric current
will alternately become the cathode. The anti-cathode will then be rendered
luminous on both sides, and the light will be absolutely steady.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed we declare that what we
claim is
1. The combination with apparatus for producing radiation by electricity of
means for maintaining a constant or approximately constant vacuum or degree
of attenuation of the gas or air in the exhausted vessel by liberating therein or
admitting thereto air or other gas by the automatic action of the electric current
substantially as hereinbefore described.
2. In combination with apparatus for producing radiation by electricity a
regulator in a shunt circuit from, and of higher resistance than, the principal
circuit, in which shunt circuit is a device, in communication with the exhausted
vessel, for generating air or gas when the current passes through the said shunt
circuit on the rerefaction in the main circuit rising above a given degree; and
thereby liberating air or gas in, or admitting it to, the said exhausted vessel.
3. A lamp for giving light by the radiation from a cathode or cathodes im-
pinging on an anti-cathode made of a material which can be rendered incandescent
such as refractory oxide of thorium or other refractory oxides or earths and con-
tained in an exhausted vessel in combination with a regulator for maintaining a
constant vacuum or degree of attenuation of air or gas in the said exhausted vessel,
substantially as hereinbefore described.
Dated: 02.1 d... of T... 1907
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, London, W.C., Agents.