Year: 1886

page_text: Date of Application, 30th Sept., 1886.
Complete Left, 30th June, 1887.
Complete Accepted, 2nd Aug., 1887.
TARNELL RABBIDGE UI Ulice fou, lapanui isturen, New Zealand
do hereby declare the nature of this invention to be as follows :-
This Invention has for its object improvements in telephonic apparatus and circuits
by which I obtain great distinctness in articulation even when working over consider-
able distances.
To secure this object I place in a telephonic circuit a material of which the resistance
varies according to the pressure given to it, and to apply different pressures I employ
the magnetic attractions of a permanent or electro magnet in a local circuit.
The magnetic attractions aforesaid are regulated by increasing or diminishing the
current in the circuit which surrounds the magnet and for this purpose the circuit is
completed through a telephone instrument which is capable of varying the current
according to the impulses of the sound waves which it receives.
The aforesaid material which I place in the telephonic circuit may be in the form
of pencils, buttons, plates, granules or powder of either carbon or any other material
capable of varying in resistance according to the variations in the pressure given to it.
The material I find best for this purpose is a mineral ore preferably Chalcopyrites
or pyrites. I prefer that this material should be confined between two metallic discs
by means of an elastic envelope which maintains constantly a slight compression.
In place of arranging the material of varying resistance in the telephonic line
circuit it may be in another circuit inductively connected with the telephonic line. In
this case the telephonic line may be put to earth at each end, no battery being
included in the circuit. Or there may be opposed batteries one at either end of
this line.
Dated this 30th day of September 1886
CARPMAEL & Co.,
Agents for the Applicant.

page_text: I, PARNELL RABBIDGE of Office Road, Papanui Road, Christchurch, New Zealand,
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:-
This invention has for its object improvements in telephonic apparatus and circuits
by which I obtain great distinctness in articulation even when working over consider-
able distances.
To secure this object I place in a telephonic circuit a material of which the resistance
varies according to the pressure given to it, and to apply different pressures I employ
the magnetic attractions of a permanent or electro magnet.
The magnetic attractions aforesaid are regulated by increasing or diminishing the
current in the circuit which surrounds the magnet and for this purpose the circuit is
completed through a telephonic instrument which is capable of varying the current
according to the impulses of the sound waves which it receives.
The aforesaid material which I place in the telephonic circuit may be in the form of
pencils, buttons, plates, granules or powder of material capable of varying in resistance
according to the variations in the pressure given to it.
The material I find best for this purpose is a mineral ore preferably chalcopyrites
or pyrites. I prefer that this material should be confined between two discs by means
of an elastic envelope which maintains constantly a slight compression.
In place of arranging the material of varying resistance in the telephonic line
circuit it may be in another circuit inductively connected with the telephonic line.
In this case the telephonic line may be put to earth at each end, no battery being
included in the circuit. Or there may be opposed batteries one at either end of this
line.
In order that my invention may be fully understood and readily carried into effect
I will proceed to describe the annexed drawings which illustrate three arrangements
from which I obtain good results.
In Figure I, M is a permanent or electro magnet, it is screwed into an iron foot
and is hollow to allow a rod of brass N to pass through its centre, one end of this rod
is fixed to the thin disc or circular plate of iron D, which is fastened by its edges to a
suitable support or a strip of thin iron fastened at its ends will serve the same purpose.
11' are side pieces of iron connecting the plate D magnetically with the lower end
of the magnet M. The other end of the rod N is secured to the disc X of the
apparatus T.
A section of the part T is shewn full size in Figure I*.
Tis an apparatus containing a semi-conducting material preferably finely granulated
Chalcopyrites, this material is enveloped and held closely together by an elastic
covering of india rubber or other substance. This material is interposed between two
discs X and Y. The disc Y. abuts upon an adjusting screw.

page_text: C is a coil of wire surrounding the magnet M and completing a local circuit
through K which is an instrument capable of varying the current according to the
impulses of the sound waves which it receives.
The instrument K may be a Bell telephone transmitter or any other transmitter.
The drawing indicates two cells of the battery B in circuit with this instrument
and the magnet coils.
R and R are the receivers in the line circuit.
The current in the line wire passes from the battery through the discs Y and ✗
and the granulated chalcopyrites between them to the stem N and disc D and by
these to line and the receiving telephones. The return may be earth as the drawing
indicates.
There are other ways in which the circuit can be arranged with advantage as
shewn in Figures II and III.
Figure II is the same as Figure I but with an induction coil introduced in the
circuit of which P is the primary and S the secondary coil. The primary P forms
part of the circuit in which the apparatus T is included."
I find the best way of arranging the telephonic circuit is that shewn in Figure III.
One pole of the battery B is connected to both the primary P and secondary S of
the induction coil, the other end of the primary P is connected to the disc X of the
apparatus T and the other disc Y is connected to the other pole of the battery B which
pole is also connected to earth at E.
The other end of the secondary-coil S is connected to line and through the
receivers R and R₁ to the other station as shewn to the right of Figure III. This
station is arranged in a precisely similar manner to that already described in the left
of Figure III.
By this means I keep the two like poles of the batteries to line. I thus provide for
any leakage in the line, and so overcome the bad effects of induction in cables or
underground wires.
Figure III also shews the apparatus K included with the apparatus T to form the
circuit through the primary coil P.
In this Figure also another method of introducing the chalcopyrites or other like
material in circuit is indicated viz., by interposing it between the poles of the
magnet M and the dise or strip D-the granulated chalcopyrites is laid on a dise of
platinum foil resting on the magnet pole and another like disc is interposed between
the chalcopyrites and the disc or strip D. The chalcopyrites and the surfaces between
which it is retained are enveloped in thin india rubber.
Instead of granulated the material may be in form of pencils, plates, buttons, &c..
The apparatus T may be connected with a disc on which voice sounds are made to
impinge directly but it is preferable to employ a magnet and additional circuit as
previously described.
The telephone transmitters I prefer to use are as shewn in Figures IV and V.
Figure IV is a vertical section. G is the mouth piece, at the back of which there
is a plate D, fixed at one end by a hinge, or spring, or resting on a pivot e. At the
other end of the plate D, there is fixed a plate, pencil, or button of a material varying
in resistance according to pressure. This plate or piece rests on another piece of
similar material and a wire is attached to each piece so that the circuit is completed
through them.
Figure V is a vertical section of a similar instrument; the plate D is held by means
of a spiral spring, and at the back of it there is a pencil of the same material, which
is adjusted by means of an adjusting screw so as to touch lightly on to the centre of
the plate D.
Figure VI shows an instrument combining the induction coil, the apparatus T and
the receiver R of the previous figures all in one. The magnet is composed of two
tubes or cylindrical pieces of iron, the inner tube C is about a " in diameter, the
outer about 1" in diameter. One extremity of the outer tube C is closed by an end
piece and the inner tube C¹ is attached to it so as to form a magnetic connection,
C and C being the two poles of the magnet. The inner tube is surrounded by a coil

page_text: of wire forming the primary of the induction coil P. Around the outer tube is wound
the secondary coil S. In front of the poles of the magnet there is a disc of iron
about 1" in diameter which forms the vibrating arinature. Through the centre of
this disc is fixed a rod of ebonite or other material, and one end of this rod is fixed to
the diaphragm F. The other end of the rod passes through the centre tube and
abuts upon one of the discs of the apparatus T; the other disc being supported and
connected as before described.
Figure VII shows the method in which the connections are made the circuit being
similar to that shewn and described in Figure III. The end of the magnet CC with
its primary and secondary coils is indicated and the parts T and K are detached that
the circuits may be clearly traced.
By this invention as described in the above Specification I am able to obtain great
distinctness and loudness in the sound emitted by the receiver even over considerable
distances.
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. A telephonic line circuit including a material the resistance of which is altered
by change of pressure resulting from the varying influence of a magnet controlled by
a current which is made to vary in accordance with the impulses of sound waves
substantially as described.
2. A telephonic line circuit which is inductively connected with another circuit
including a material the resistance of which is altered by a change of pressure
resulting from the varying influence of a magnet controlled by a current which is
made to vary in accordance with the impulses of sound waves substantially as
described.
3. A telephonic line circuit including opposed batteries and also inductively
connected with another circuit in which the current is made to vary in accordance
with the impulses of sound waves; such circuit including a material the resistance of
which is changed by the influence of sound waves operating either directly or by the
aid of another circuit and magnet substantially as described.
4. The apparatus T consisting of granulated chalcopyrites or pyrites compressed
between discs X and Y and enclosed in an elastic envelope, such apparatus forming
part of a battery circuit and controlling the current therein in accordance with the
'impulses of sound waves operating either directly or by the aid of another circuit and
magnet, substantially as described.
5. A plate, pencil or button which is held by a hinge, spring, or pivots and resting
lightly on to a surface of a material, so that the resistance between the two points
varies according to the vibration caused by the sound waves substantially as described
in Figures IV and V.
6. The combination of induction coil and receiver as described and illustrated in
Figures VI and VII.
7. My improvements in telephonic apparatus and circuits substantially as described
and illustrated by the annexed drawings.
CARPMAEL & Co.,
Agents for the Applicant.