IMPROVEMENTS IN ELECTRIC TELEPHONY AND IN TELEPHONIC APPARATUS
Year: 1877

page_text: LETTERS PATENT to Charles Weightman Harrison, of South Kensington, in the
County of Middlesex, Gentleman, for the Invention of "IMPROVEMENTS IN
ELECTRIC TELEPHONY AND IN TELEPHONIC APPARATUS."
ealed the 25th June 1878, and dated the 29th December, 187
PROVISIONAL SPECIFICATION left by the said Charles Weightinan
Harrison at the Office of the Commissioners of Patents on the 29th December
1877.
CHARLES WEIGHTMAN HARRISON, of South Kensington, in the County of Middle-
sex, Gentleman. "IMPROVEMENTS IN ELECTRIC TELEPHONY AND IN TELEPHONIC
APPARATUS."
This Invention relates to improvements in electric telephony and in telephonic
apparatus.
The first part of my Invention relates to the construction of an electric telephone
of great sensitiveness and simplicity by means of utilising a thermo-electric battery
arranged in a manner suited to the object in view. One method by which I am
thus enabled to carry on conversation at a distance through a connecting wire or
line consists in speaking direct upon the electrodes of a therino battery, or upon one
of the electrodes or upon some suitable surface connected with them, and thus
produce from the warmth of the breath a thermo-electric bent or wave corre-
sponding with the air wave produced by the voice.
In some cases when I desire to increase the effect I use by pressure the warmth
of thumb and finger upon the electrodes at or near their point of junction. The
sounds transmitted may be amplified by any known suitable means.
Another part of my Invention relates to the employment of a galvanic or voltaic
battery for the production of the electricity, the electrodes being separated by a
moistened substance or material, and the beat or wave of electricity necessary to
reproduce the sound to be conveyed being produced, as in the former case, by
speaking on to the electrode, or by other sound impinging on the electrode. The
plates may be flat or curved on surface.

page_text: My Invention relates, thirdly, to the employment of flat or other spiral or coils
of wire (by preference of iron) attached at each end of or at stations on the lino
wire. The words to be conveyed are spoken on to one or more of these coils, and
received at the other end by similar coil or coils. Other sound may be similarly
conveyed. The coils may be employed with or without a local battery. Sometimes
the coils are made a source of electricity by being constructed compound, i.., of
more than one metal, or by coating them with magnetic sand, or by other suitable
means.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Charles Weightinan Harrison in the Great Seal Patent Office on the
29th June 1978.
CHARLES WEIGHTMAN HARRISON, of South Kensington, in the County of Middle-
sex, Gentleman.
"IMPROVEMENTS IN ELECTRIC TELEPHONY AND IN TELEPHONIC
APPARATUS."
The first part of my Invention relates to the construction of a electric telephone
of great sensitiveness and simplicity by means of utilising a thermo-electric battery
arranged in a manner suited to the object in view. One method by which I am
enabled to carry on conversation at a distance through a connectiug wire or line
consists in speaking direct upon the electrodes of a thermo battery, or upon one of
the electrodes, or upon some suitable surface connected with them, and thus
producing from the warmth of the breath a thermo-electric beat or wave corre-
sponding with the air wave produced by the voice.
Figure 1 is a front or face elevation, and Figure 2 a transverse sectional elevation
of a thermo battery in its simple forin, which I have found to be well adapted for
the purposes of my Invention. A is a ring of amalgamated copper, lead, or other
suitable metal in slight adjustable contact with a disc of carbon B, which is attached
by glue or by other suitable means to a block of wood C, the adjustment of the
contact between the electrodes being effected by the said screws D passing through
the bridge E. The face and handle F are of wood, the former having the form
shewn to guide the air waves, and the latter being hollowed out to allow the wires
from the two electrodes to pass down to the terminals G, to which also the line
wires H are communicated. The words to be conveyed should be directed towards
and be spoken near to the face of the carbon plate B.
Figure 3 is a front elevation, and Figure 4 a side elevation of another form of
the single pair electrode thermo battery, in which the mechanism is constructed of
great delicacy and lightness, so that a very faint sound will cause it to act
efficiently. A is a carbon plate suspended on pivots at its upper end, and when
vertical is in very light contact with a shoe B (carbon faced), which is capable of
adjustment relative to the plate A. When the shoe is drawn towards the plate A
the latter is put out of the vertical, and so presses more on to the shoe, giving

page_text: greater contact.
The adjustment may be further effected by the set screw C. The
voice should be directed on to the plate A, as in the previous case.
Figure 5 is a face view, and Figure 6 an end view of a thermo battery with six
pairs of elements. These consist of wires A attached and in contact by hook and
eye arrangement, the wires passing round a block of wood with a terininal at each
end, to each of which an end wire is attached, the wires being alternately different
metals, by preference amalgamated copper and platinised lead." C is the mouthpiece
for directing the air waves into the wire elements.
Figure 7 is a face view, and Figure 8 an end view of a similar battery, the
difference being that the alternate wires instead of being connected by hook and
eye arrangement have their ends laid in contact in pairs in carbonised grooves
burnt in the face of the block B.
In some cases when I desire to increase the effect by a more powerful current I use
in addition to the warmth of the breath that of the thumb and finger by touching
the electrodes or the terminal; I thus produce a continuous current to be varied by
the waves of sound and heat emanating from the breath. In all these forms
of thermo battery the warmth of the breath should be brought to bear on the
electrodes.
Figure 9 is a side elevation, and Figure 10 a plan of another part of my Invention
relating to the employment of a galvanic or voltaic battery for the production of
the electricity, the electrodes being separated by a moistened substance or material,
and the beat or wave of electricity necessary to reproduce the sound to be conveyed
being produced, as in the former case, by speaking on to or in this case by other
sound impinging on the electrode. A is a box containing a positive or zinc elec-
trode B, upon which is placed a placed a piece of cloth C or other suitable material
moistened by a saline solution. Upon this is laid one-half of a negative electro le D,
which may be of carbon, and upon this edgewise rests the lower part D₁ of the
electrode. It is pointed at the lower end, and rests in a groove, the upper end
being supported by a contact and adjustment screw E, the screw passing loosely
through the carbon. Whilst the carbon is vertical the contact is very light, but on
being inclined by the screw to the right the pressure on the contact button at the
end of the screw E is increased, the strength of contact being thus capable of
adjustment.
My Invention relates, thirdly, to the employment of flat or other spirals or coils
of wire attached at each end, or at stations on the line wire. The words to be
conveyed are spoken on to one or more of these coils, and received at the other end
by similar coil or coils. Other sound may be similarly conveyed. The coils may
be employed with or without a local battery. Sometimes the coils are made a
source of electricity by being constructed compound, i.e., of more than one metal, or
by coating them with magnetic sand, or by other suitable means,
For
In my experiments I have found that the conducting wire of the circuit will
produce sonorous vibrations in accordance with the variations in the current.
this purpose I prefer that the spiral should be of soft iron, and that it should be
stretched over a sounding board with a moderate degree of tension.
The spiral is supported at intervals of the nodal points, or it may be so constructed
in sections, the supports or ends of each section resting in light contact with said
supports or with each other, so as to prevent increased resistance to the passage of
the current at such nodal points. In place of using one uniform size and quality of
wire I find it advantageous to use in each of the several sections wire of different
thicknesses in proportion to the pitch of the notes, which is well understood; these
wires may be straight or bent with their nodal points or ends resting on blocks of
carbon, each block being in the circuit of the current which is dispersed at these
points according to the unison of pulsations and vibrations.
In the course of my investigations I have found that these spirals may be used
in circuit with the sound of a standard clock, and thus form correct chronophones
for repeating the hour in different places.

page_text: Figure 11 is a plan view of a spiral showing the nodal points and a sounding
board underneath.
In order to converge the sound waves upon the coils I place a trumpet mouth-
piece over them of suitable dimensions.
Figure 12 illustrates a vertical sectional elevation, and Figure 13, in plan, a
receiver constructed according to my Invention. A is the stand capable of adjust-
ment as to height, as shown. Surmounting the top is an horizontal cylinder B
filled with discs of carbon C, through the centre of which passes a rod D, at one end
of which is a button E of vulcanite or ivory, and at the other a screw thread and
nut, by which the contact of the discs may be increased in pressure or diminished.
F is the mouthpiece for directing the sound waves on to the discs of carbon. From
each of the end discs a wire is led down to a terminal at the base of the instrument.
The current passes through the instrument, and the air vibrations entering the said
mouthpiece are communicated to the current causing undulations.
According to one method of carrying my Invention into effect I have found that
the surface to be connected with the electrodes may consist of two or more plates or
discs to act as condensers, as shown at Figures 14 and 15, Figure 14 being a face
view, and Figure 15 a side view. There are connected with the line wire and the
battery, or with a secondary coil, the current being led through the binding
screws A, B, to the terminal discs C, C, which are of metal or other suitable
material held in the brass frame or ring that adınits of a nice adjustment by the
screws D and slide E at a very small distance apart according to the degree of
potential. I have also found carbon discs or cylinders to be powerful condensers on
account of the immense surface which it exposes in proportion to its size. It is,
however, advisable to coat or varnish its back or inargin.
When it is desired to keep a record of the sounds made I conduct the electric
current passing through the receiver through the coils of an electro-magnet which
carries a point upon its armature to indent or mark upon a movable surface after
the manner of a Morse instrument.
The sounds transmitted may be by any known suitable means. A convenient
arrangement of repeater for this purpose consists in an electro-magnet and metal
diaphragm, which latter I prefer to make of well annealed iron, as bare as
possible; this is best obtained by electro deposition. The diaphragm should be as
thin as possible at the centre (having regard to continuity), increasing in thickness
towards the margin to about 7 or 8 times its thickness, and thus present a somewhat
concave face towards the mouth of the receiver, of which Figure 16 is a side
elevation, and Figure 17 a cross section on the line A, B, Figure 16. I arrange the
electro-magnet with south polarity opposite the centre or thin part of the disc, and
north polarity at the margin or thicker part of the disc, as shewn in the cross
section. Adjustment is made between the discs and poles of the magnets by screw
adjustment, as shown at Figure 16.
I claim as my Invention the improvements in electric telephony and in telephonic
apparatus, substantially as herein-before described and illustrated.
In witness whereof, I, the said Charles Weightinan Harrison, have hereunto
set my hand and seal, this 29th day of June, in the year of our Lord One
thousand eight hundred and seventy-eight