IMPROVEMENTS IN ILLUMINATING CONDUCTORS FOR INCANDESCENT ELECTRIC LAMPS
Year: 1882

page_text: LETTERS PATENT to Geminiano Zanni, of Charles Street, Hatton Garden
in the City of London, Electrician for an invention of "IMPROVEMENTS IN
PROVISIONAL SPECIFICATION left by the said Geminiano Zanni at the
Office of the Commissioners of Patents on the 10th June 1882.
GEMINIANO ZANNI, of Charles Street, Hatton Garden, in the City of London,
Electrician, "IMPROVEMENTS IN ILLUMINATING CONDUCTORS FOR INCANDESCENT
ELECTRIC LAMPS
"
My Invention relates to illuminating conductors for electric lamps of that class
in which the light is developed by the passage of a current of electricity through,
or over, a strip or loop of suitable material which is thereby rendered
incandescent.
The material, such as carbonized cardboard and like substances heretofore used
for making the strip or loop which is to emit the light when rendered incandescent
by the electricity, is, as is well known, a bad conductor, and as it consequently
opposes great resistance to the passage of the current, the battery or other
electrical generator must be of considerable power in order to produce the required
light in the lamps.
My Invention is designed to provide strips, pieces, or webs so made that while
they will be rendered incandescent by the electric current will offer considerably
less resistance to the passage thereof than is the case with the strips or loops
heretofore employed and thus effect a large economy with respect to the expenditure
or consumption of electricity.
In carrying my said Invention into practice I make, in the following manner,
the part which is to be rendered incandescent, that is to say, I provide a core of
thin wire which I insert within a fine Tuscan straw the latter thus forming a tube
around the wire. The whole is then bent to the required form and subjected to
heat so that the straw becomes carbonized. The wire and the carbon forin, as it

page_text: were, one solid piece that is to say, the carbon will entirely and closely surround
the wire which forms a core thereto. Instead of the straw I may, in some cases,
use other carbonized material in the form of powder or in other form which will
he secured to the wire core by any suitable means.
The strips or pieces of carbon-covered wire so made are inserted within the
globes or vessels which are to surround them, in the ordinary manner, passing
through glass or other plugs in which they are embedded, and the ends of the
strips are secured to the wires leading from the battery or other generator.
By reason of the nature of my improved strips or pieces they may be readily
bent into a variety of forms, that is to say, I may either make a single loop thereof
or I may make the same so as to form a zig-zag or other figure, or I may so twist
and bend the strip as to form quite a web each part of which will be rendered
incandescent when the electric current traverses the same. It will be thus seen that
the light may be increased to almost any extent, the carbon-covered wire being
capable of being bent a considerable number of times without risk of the circuit
being interrupted by breakage, whereas with the slender and delicate filaments
heretofore employed such bending is not practicable.
I prefer to use platinum wire as the core but do not confine myself to this
material as other wire may be employed.
According to another method of carrying my invention into practice I take a
thread or strand of silk, cotton, wool or any other suitable fibrous or other
material and carbonize the same so as to form a filament of carbon and I then
coat this filament with platinum by electro platinizing the same in such a manner
that there will be a core of carbonized material and an outer metallic surface.
This arrangement will also have the effect of reducing the resistance in the portion
of the lamp which emits the light and will thus effect the object of my invention.
In some cases I platinize only a portion, say one half, of the surface of the carbon.
My Invention may be readily applied to any of the existing incandescent lamps
and I may use, in combination with my improved strips or webs, any suitable gases
within the globe.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Geminiano Zanni in the Great Seal Patent Office on the 9th December
1882.
GEMINIANO ZANNI, of Charles Street, Hatton Garden, in the City of London,
Electrician. "IMPROVEMENTS IN ILLUMINATING CONDUCTORS FOR INCANDESCENT
ELECTRIC LAMPS
"
My invention relates to illuminating or light-emitting conductors for electric
lamps of that class in which the light is developed by the passage of an electric
current through or over a strip or loop of suitable material which is thereby
rendered incandescent.
Heretofore, carbonized-cardboard and like substances have been used for making
the strip or loop which is to emit the light when rendered incandescent by the
electric current. It is well known that such materials are bad conductors of
electricity, and, as they consequently offer great resistance to the passage of the
current, the battery or other source of electricity must be of considerable power in
order to produce the required light in the lamps.
My invention is designed to provide strips or filaments which, while they will
be rendered incandescent by the electric current, will offer considerably less
resistance to the passage thereof than the strips or loops heretofore employed, so
that I am enabled to effect great economy with respect to the expenditure or
consumption of electricity. According to my said invention the strips or filaments
are composed of carbonized material combined with platinum, iridium, or similar
metal, as hereinafter set forth.
One method of carrying my invention into practice is as follows, that is to say:-
I take a thread or strand of silk, cotton, wool or any other suitable material and
bend the same to the desired shape, I then carbonize the same so as to form a
filament of carbon, and I coat this filament with platinum, iridium, or similar
metal, either by means of electricity or by treating it in a solution suitable for
the purpose; I then cover the filament thus prepared by depositing thereon a
coating of carbon by means of any suitable gas, thus producing a metallic lining
between two bodies of carbon. This outer coating of carbon serves to protect the
metal. The said metallic lining I make of greater or less thickness in order to
vary the resistance to the current according to the amount of candle-power of the
light to be produced, and the electro-motive force must be varied accordingly. By
reason of the said lining and coating, a white light is produced superior to that
obtained with the ordinary carbon filaments. This arrangement will also have the
effect of reducing the resistance in the portion of the lamp which emits the light,
and will thus attain the object of my invention. In some cases I treat only a
portion, say one half, of the surface of the carbonized filament in the manner above
described.
I sometimes make the said filaments in the following manner, that is to say :-
I provide a core of thin wire which I insert within a fine tuscan straw, the latter
thus forming a tube around the wire. The whole is then bent to the required
shape and subjected to heat so that the straw becomes carbonized. The wire
and the carbon form, as it were, one solid piece, that is to say, the carbon will
entirely and closely surround the wire, which forms a core thereto. Instead of
covering the wire with the straw, I, in some cases, cover it with a coating of
carbon by means of gas or in any other suitable manner. These filaments composed
of wire, covered or coated with carbon, can be used for electric lighting without
the necessity for creating a vacuum in the globe or vessel containing them.

page_text: The strips or filaments manufactured as above described are inserted, in the
ordinary manner, within the globes or vessels which are to surround them, and
they pass through glass or other plugs in which they are embedded, the ends of
the said strips or filaments being secured in any suitable manner to the wires
leading from the battery or other source of electricity.
I can manufacture my improved strips or filaments in a variety of forms, such
as a single loop or a zig-zag or other figure. In some cases I make the strip in
the form of a web so as to increase the power of the light emitted thereby.
I prefer to use platinum or iridium for the above described purposes, but I do
not confine myself to this material, as other metal may be employed.
My invention may be readily applied to any of the existing incandescent lamps
and I may use in combination with my improved strips or filaments, any suitable
gases within the globe.
Having thus fully described my said invention and the manner of performing
the same I wish it understood that I Claim :-
First An illuminating or light-emitting conductor composed of a wire of
platinum, iridium or similar metal covered or coated with carbon, substantially as,
and for the purpose, set forth.
Second: An illuminating or light-emitting conductor composed of a thread of
silk, cotton, or other suitable material bent into the desired form and carbonized,
then covered or coated with platinum, iridium or similar metal, which is then
coated with carbon, substantially as set forth and for the purposes specified.
In Witness whereof I the said Geminiano Zanni have hereunto set my
band and seal this Ninth day of December in the year of our Lord One
thousand eight hundred and eighty two.