IMPROVEMENTS IN APPARATUS OR APPLIANCES FOR OBTAINING ELECTRIC LIGHT
Year: 1879

page_text: LETTERS PATENT to Gustavus Palmer Harding, of No. 66, Avenue de Champs
Elysees, Paris, in the Republic of France, now residing at the Buckingham
Palace Hotel, in the City of Westminster, for the Invention of "IMPROVEMENTS
IN APPARATUS OR APPLIANCES FOR OBTAINING ELECTRIC LIGHT."
PROVISIONAL SPECIFICATION left by the said Gustavus Palmer Harding
at the Office of the Cominissioners of Patents on the 26th February 1879.
GUSTAVUS PALMER HARDING, of No. 66, Avenue de Champs Elysees, Paris, in
the Republic of France, now residing at the Buckingham Palace Hotel, in the City
of Westminster. IMPROVEMENTS IN APPARATUS OR APPLIANCES FOR OBTAINING
ELECTRIC LIGHT."
"
This Invention has for its object improvements in obtaining electric light.
I obtain a very intense light from a surface of lime or refractory earth, which I
heat by means of electricity.
I enclose for this purpose a pencil of carbon in a sheath of lime or refractory
earth, and by passing an electric current through the carbon I cause it and its
sheath to become very highly beated.
Or in place of carbon a metallic conductor may be employed. It may be used
with a regulator, which will prevent the temperature rising so high as to fuse the
metal, or the sheath may be suitably formed to retain the metal after fusion has
taken place. Or in cases when the metal is not allowed to fuse it may be coiled
around or otherwise placed in close proximity to a pencil of lime or refractory
earth, so that the same may be made highly luminous by the passage of the current
in the metal. I in some cases employ electrodes of carbon intimately combined
with lime or refractory earth.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Gustavus Palmer Harding in the Great Seal Patent Office on the
26th August 1879.
GUSTAVUS PALMER HARDING, of No. 66, Avenue de Champs Elysées, Paris, in
the Republic of France, now residing at the Buckingham Palace Hotel, in the City 6
of Westminster. "IMPROVEMENTS IN APPARATUS OR APPLIANCES FOR OBTAINING
ELECTRIC LIGHT."
This Invention has for its object improvements in apparatus or appliances for
obtaining electric light.
I obtain a very intense light from a surface of lime or refractory earth, which I 1
heat by means of electricity.
I enclose for this purpose a pencil of carbon in a sheath of lime or refractory
earth, and by passing an electric current through the carbon I cause it and its
sheath to become very highly heated.
Or in place of carbon a metallic conductor may be employed. It may be used 1
with a regulator which will prevent the temperature rising so high as to fuse the
metal, or the sheath may be suitably formed to retain the metal after fusion has
taken place. Or in cases when the metal is not allowed to fuse it may be coiled
around or otherwise placed in close proximity to a pencil of lime or refractory earth,
so that the same may be made highly luminous by the passage of the current in
the metal.
The earths that may be employed in carrying out my Invention are lime in
different forms, zirconia, magnesia, plaster of Paris, and similar material. In some
cases, to give them cohesion, they may be usefully mixed with asbestos. I find that
a very small portion of such material as lime or chloride of magnesia will suffice
when employed in the electric arc to give a brilliant and agreable light. The
simply chalking slightly one side of the carbon pencils used as electrodes has a
sufficient effect, and in order to avoid the accumulation of the fused material, which
would impede the passage of the electricity, the use of an alternating current is
preferable.
A convenient method of obtaining the result sought is to arrange two discs of
carbon, as shewn at Figure 7, in such manner as to revolve automatically, sufficiently
distant from each other for the current to form the arc when passing from one to the
other, the said discs being in connection with an electric generator. The application
to the edge of one or both of the carbon discs, while revolving, of a piece of properly
prepared lime or other suitable refractory earth suffices to give a coating which
modifies considerably the brilliancy and the tone of the light produced; the dotted
lines a, a, represent bands of lime or other such like material so formed around the
surface of carbon discs b. A convenient way of forming such bands is to cause a
disc of lime or such like material to revolve and rub against the surface of the
carbon discs.
Figures 1 to 7 are different methods in which the material may also be employed
in the manner explained. In these Figures the parts marked a, a, are of lime or
other refractory earth; the parts marked b are the carbon electrodes. The lime or
other earth does not in itself act as a burner in the ordinary sense of the term, but
as an aid which is intended to increase the light by its incandescence, and at the
same time diminish the consumption of the carbons.
In the use of zirconia or such other refractory earths as are practically incom-
bustible they may be placed as a nozzle on the carbon in the form of a hollow cone,
with an opening sufficiently large to allow the current to pass from the one carbon
to the other, and to form the electric arc, which will render the zirconia incandescent.
The light in this case will come principally from the zirconia, and the consumption
of the carbon will be small.

page_text: In the case of parallel carbons a plate of lime at right angles with one which
separates the two electrodes, but forming the base of the said plate, may be used, as
shewn at Figure 6, to aid in reflecting the light, and will be found to increase it
considerably.
Another method is to form a cup or small reservoir of refractory earth, in which
is placed platinum so arranged as to be in connection with an electric generator, in
order that it may be fused and render brilliantly incandescent the vessel of refrac-
tory earth in which it is contained, and this with a view of utilizing not only the
incandescence of the earth, but the increased luminosity of ignited platinum, which
increases rapidly when heated beyond 2000 degrees.
Having thus described the nature of iny Invention and the manner of performing
the same I would have it understood that what I claim is,-
First. The methods of using refractory earths in connection with carbon or other
electrodes, substantially as and for the purposes hereinbefore described.
Second. The means and appliances for obtaining electric light, substantially as
herein before described.
In witness whereof, I, the said Gustavus Palmer Harding, have hereunto
set my hand and seal, this Twenty fifth day of August, in the year of our
Lord One thousand eight hundred and seventy nine.