IMPROVEMENTS IN METHODS OF AND APPARATUS FOR TRANSMITTING AUDIBLE ȘIGNALS BY MEANS OF ELECTRICITY
Year: 1883

page_text: LETTERS PATENT to Arthur French St. George, of Finsbury Pavement, in the
City of London for an Invention of " IMPROVEMENTS IN METHODS OF AND
APPARATUS FOR TRANSMITTING AUDIBLE ȘIGNALS BY MEANS OF ELECTRICITY"
PROVISIONAL SPECIFICATION left by the said Arthur French St. George
at the Office of the Commissioners of Patents on the 21st February 1883.
ARTHUR FRENCH ST. GEORGE, of Finsbury Pavement, in the City of London
"IMPROVEMENTS IN METHODS OF AND APPARATUS FOR TRANSMITTING AUDIBLE
SIGNALS BY MEANS OF ELECTRICITY "
My invention relates to improvements in apparatus used for transmitting and
reproducing audible signals by means of electricity, and in methods of so trans-
mitting such signals, and it has for its objects novel methods of constructing,
arranging and operating such apparatus, so that messages can be readily transmitted
for long distances and the apparatus is very effective and easily worked, whilst the
interference of inductive action upon the transmitting wire or wires is reduced or
prevented.
The first part of my invention relates to a novel form of transmitting apparatus
by which such messages are sent. I take a disc of wood or other analogous organic
material which I carbonize so as to obtain a disc of hard carbon of uniform
character having great capacity of resonance by vibration. This disc is made to
vibrate, by the human voice or other sounds, in contact with or together with
electrical contact pieces of the ordinary well known kind which are arranged in
connection with a wire or wires or other conductors through which an electrical
current is passed, in which undulations are produced corresponding with the
vibrations caused by the sounds to be re-produced which impinge upon the disc.
Another part of my invention relates to a receiver for receiving and rendering
audible the undulations so transmitted.
It consists of a disc of mica one side of which is coated by electro-deposition in
any of the well-known ways, or otherwise, with a film of metal or other conducting
material. This disc is connected with one of the wires in or connected with the
telephone circuit through which signals are to be transmitted, and the uncoated
Povine 21

page_text: side is brought into close proximity with a block or disc of metal or with a
similarly coated mica disc, their proximity being regulated by an adjusting screw
so that they are nearly in contact. The block or disc last described is connected
with one wire through which electrical undulations are transmitted and the disc
first described with the other wire. Each electric charge communicated in this way
to the first disc will cause it to be attracted to the other block or disc, and these
attractions corresponding with the electrical undulations caused in the wire as
described the sounds by which they are caused will be reproduced in the receiver.
A third part of my invention relates to a novel form of apparatus for recording
and reproducing the sounds transmitted by the human voice or otherwise through ]
telephonic wires. I arrange a flat disc of transparent glass so that it can be made
to revolve when desired upon an axis in suitable bearings.
I coat the surface of this glass disc with a film sensitive to the action of light, of
the kind ordinarily known and used in photographic processes, and the apparatus
being then adjusted in a dark chamber I arrange a small aperture through which a
beam of light is made to fall upon the sensitized surface of the disc. The aperture
is made moveable and is connected with the bearings in which the disc revolves in
such manner that as the latter is turned the ray of light moves slowly from the
circumference toward the centre of the disc, or vice versa, so that the point on the
latter where it falls describes a spiral line on the disc.
The size or width of the aperture is made variable so that the width of the ray
of light can be made variable in a corresponding degree, and a sonorous telephonic
diapliragm is connected to it in such manner that as the diaphragm-vibrates it
varies with each vibration the effective width of the aperture and of the ray of
light. The spiral line impressed or made upon the sensitized surface of the ray of
light impinging upon it will therefore vary in width according to the extent and
character of each vibration of the diaphragm. When impressions have thus been
photographically made upon the glass disc to a sufficient extent, they are developed
and fixed in the usual well known way.
"
The disc is then replaced in its bearings and whilst made to revolve a strong ray
of light is made to fall upon the spiral line and through the glass upon selenium or
other suitable material with which a telephonic receiver is in connection, and the
varying intensity of the light falling upon the selenium according to the variation
in the photographically produced spiral line causes corresponding variations or
undulations in the electric current passing through the selenium and through the
telephone receiver, and the latter will reproduce audibly the sounds originally sent
through the telephone the diaphragm of which reguintes the size of the opening
through which the ray of light passes as already described.
Another part of my invention relates to a novel form of telephone transmitting
apparatus. This consists of an ordinary glass disc or other well known device by
which frictional electricity can be generated, and retained in an insulated receiver.
A wire conducts this electricity to a disc of thin metal, or preferably-of mica
coated with conducting material as already described, in front of which is adjusted
an ordinary telephone mouthpiece.
Parallel with this disc and in near proximity with it is arranged a corresponding
block or disc of metal with which the insulated wire of the telephone circuit is
connected. The other end of the wire is connected to a corresponding metallic
block or disc in sufficiently close proximity to a second telephone disc. When a
charge of electricity is supplied to the first or transmitting disc and the latter is
made to vibrate by the human voice or other sounds, corresponding undulations of
electricity pass through the wire of the circuit to the receiving disc or block, the
telephone disc in proximity with which is attracted at each such undulation, and
the sounds transmitted from the first disc are thus reproduced.
Another part of my invention relates to novel methods of preventing the
inductive action upon a telephonic conducting wire in a submarine or other cable of
electric currents passing through other wires in the same cable.
In a conveniently, accessible situation near the end of such submarine cable, I'

page_text: arrange an anti-inductive apparatus consisting of a sufficient number of fine parallel
insulated wires in the neighbourhood of the telegraph or other wires the inductive
action of which upon the telephone wire it is desired to neutralize.
The length and number of such fine wires are such that they are electrically
equivalent to the wire in the submarine cable and are proportioned to the length of
the latter. This anti-inductive apparatus is inserted in the telephone wire circuit,
its ends however being connected to the latter so that any current passing through
it moves in the opposite direction to that passing through the cable itself, and its
end connecting wires are brought round so as to be sufficiently removed from any
inductive action of the telegraph wires upon them.
..
By this arrangement any current caused by the inductive action upon the
telephone wire in the cable is neutralized by the corresponding current induced in
the latter but in the opposite direction from the anti-inductive apparatus described,
by the induction of the telegraph wires in the neighbourhood of the latter.
Instead of the arrangement described the telegraph wires near the ends of the
submarine cable may be connected to wire coils through which their current passes,
these coils being inserted in or made to surround other coils connected with the
telephone wire but in such manner that currents induced in the latter are in the
opposite direction to those induced in the telephone wire in the submarine cable
itself.
Another part of my invention relates to apparatus for transmitting telephonic
audible messages-across the sea.
I take two wires of dissimilar metal traversing the sea, to the water of which
they are exposed for a sufficient part of their length without being in contact with
each other. The ends of these wires are insulated, and at each end suitablé
telephonic transmitting and receiving instruments are connected to them, in such
manner that when the action of the sea water upon the dissimilar metals generates
galvanic electricity in them the action of the telephonic transmitter at one end is
to draw off more or less of such electricity from the wires or cables as the
diaphragm vibrates, and so to deprive the station at their opposite end of
correspondingly more or less current, these electrical variations being transformed
in the usual way into audible sonorous_vibrations by the receiving instruments.
My invention also relates to a novel method of winding the wire round the poles
of telephonic instruments of the ordinary well known kind, or round induction
coils, in such manner that their resistance is diminished. For this purpose instead
of using a continuous coil I take a sufficient number of insulated wire rings, each of
which is not however continuous but has a break in its circumference, one end of
each of the rings being connected to one end of the conducting wire through which
an electrical current passes or is to be generated, and the other end of each of the
rings being connected to the other end of the conducting wire.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Arthur French St. George in the Great Seal Patent. Office on the
21st August 1883.
•
ARTHUR FRENCH ST. GEORGE, of Finsbury Pavement in the City of London
"IMPROVEMENTS IN METHODS OF AND APPARATUS FOR TRANSMITTING AUDIBLE
SIGNALS BY MEANS OF. ELECTRICITY
"
My present invention relates to improvements in apparatus used for transmitting
and reproducing audible signals by means of electricity and in methods of so
transmitting such signals, and it has for its objects novel methods of constructing
arranging and operating such apparatus so that messages can be readily transmitted
for long distances and the apparatus is very effective and easily worked, whilst the
interference of inductive action upon the transmitting wire or wires is reduced or
prevented.
The first part of my invention relates to a novel form of transmitting apparatus
by which such messages are sent. I take a Disc of wood or other suitable organic
material which I carbonize so as to obtain a disc of uniform character having great
capacity of resonance by vibration and capable of conducting electricity.
In order to produce this vibratory conducting disc or plate I employ the
following process.
I take an air-tight retort of the dimensions and shape suitable for the discs or
plates, and I put therein a layer of animal charcoal upon which I place the disc or
plate of organic material and on it a metallic plate and on the latter a second disc
or plate of organic material and another metallic plate and so on until the air
tight retort is almost full and I then fill up the retort with animal charcoal. The
cover of the retort is then placed on and screwed very tightly down so that
the discs or plates of organic material cannot warp or be bent in the process of
firing. The retort so filled is then submitted to a considerable heat for a sufficient
time the amount of heat and the time, varying with the character of the material
to be carbonized and the amount of electric resistance required, for instance with
mahogany a temperature of a dull red heat for about three hours gives a satisfactory
result. With leather a similar temperature for about half the time is sufficient.
On removal from the furnace the retort is allowed to cool completely before
opening it to extract the discs which have been carbonized by the process of
heating. The free powdered charcoal in the closed retort is slightly consumed and
serves to burn out almost completely any traces of oxygen in the retort. Thus the
structure of the Discs of organic material remains perfectly preserved and whilst
they are by the process converted into pure carbon they retain their original
structure and vibrating quality particularly suitable for responding by vibration to
sounds impinging upon them. The carbonized disc is capable of conducting
electricity.
In order to transmit the sounds of the human voice I prefer to employ a
carbonized disc so prepared mounted by its edges in a frame or support between
suitable rings or washers, and sometimes I employ a mouthpiece to cause sounds
to impinge upon the disc with increased force. The Disc so mounted is placed in
a suitable containing case with an aperture to admit of sound waves impinging
upon it.
I prefer to connect the disc to the circuit in which it is to operate by means of
copper electro-plated upon a small portion of the disc preferably the edge and to
the electro-film of metal which must be in rigid contact with the disc I solder a
connecting wire for connection with the circuit. I arrange a ball of the hardest
quality of carbon hanging by a thin metallic wire or by a flexible non-metallic

page_text: thread and this ball is arranged so as to touch lightly against the surface of the
carbonized disc. I connect the ball to the electrical circuit by means of the thin
metallic wire (or if a non-metallic thread is used by a separate metallic wire of
extreme flexibility) and the circuit is completed by the contact of the ball with
the surface of the carbonized disc.
Sounds made to impinge upon the apparatus agitate the disc and the ball
touching it so that the ball follows all movements of the disc and always is in
contact with it but whilst the disc vibrates the ball makes small excursions about
the surface of the disc, that is to say, any movement of the disc causes the ball to.
roll about its surface and this rolling action of the ball brings into circuit from
time to time fresh points of contact in the path of the current of electricity.
The transmitting apparatus described is connected with a battery and conducting
wire forming a complete circuit and vibrations of the apparatus produced by sound
will set up electrical variations which at a distant point of the circuit may be
resolved into corresponding sounds in a receiving telephone.
I do not, confine myself to the aforementioned precise method of construction
and arrangement of contact piece in loose contact with the surface of the disc, nor
do I always employ the contact piece of carbon but sometimes I employ a contact
piece of metal 'lightly touching the disc and sometimes I prefer to use more than
one contact piece of carbon or metal. In all cases I prefer to correct the contact
piece or pieces to the circuit by means of a thin flexible wire or thread incapable
of giving bias to the contact of the contact piece with the disc and incapable of
impeding the motions of the contact piece and the disc which it lightly touches as
described. The contact piece may be in the form of a perfect sphere or circle or
of a ring circular or elliptic or of egg or pear shape and of such convenient form as
will roll easily about when agitated so that no matter what excursions it may
make the extent of its surface contact with the disc remains practically constant.
For the purpose of transmitting loud musical sounds I employ one or more large
discs or boards of wood or other suitable organic material carbonized as herein before
described and in connection with proportionately large carbon or metal balls, the
apparatus of such enlarged form being arranged in like manner to the human
voice transmitter-described but for loud musical sounds I prefer not to employ a
mouthpiece.
In the accompanying drawings Figures 1 and 2 illustrate this part of my inven-
tion, a is the carbonized disc or plate carried in the support c between washers c', c',
and beld by the ring f. The ball b is hung by the wire d in light contact with the
plate a, the electrical current passing through the wire d the ball 6 the plate a and
the conducting wire g at the edge of the latter. In figure 3 the ball b is shown
suspended by a thread d the electric current passing to it through a fine wire h.
Two or more moveable contact pieces may be used instead of one only, being so
arranged that the current of electricity passes through them and through the
carbonized plate either in succession or collectively, or in groups. This multiple
arrangement is illustrated in figures 4 and 5 in which thirteen balls are shown.
The circuit may be connected so that the current may pass through any or all of
the balls b, b, b, and wires d to the plate a
Another part of my invention relates to a novel form of receiver for receiving
and rendering audible electrical vibrations. It consists of two or more discs of
mica arranged parallel with and in close proximity to each other and suitably
mounted by their edges so as to be free to vibrate. One side of each disc of mica
is coated by electro-deposition with metal preferably silver, and the discs are
preferably perforated at their centre.
The mica discs are arranged so that the metal side of one disc faces the mica side
of the next disc and so on throughout the series. The discs are connected alter-
nately with each other one set of the series to one conducting wire of the circuit
and the other set of discs to the other wire of the circuit. With these novel
condenser plates so arranged advantage is taken of molecular strains of the mica
forming the dielectric of the condenser arrangement of discs, and such molecular

page_text: agitations produced by polarization of the mica discs in addition to the attractions
to each other of the plates serve to increase considerably the audible effects of the
receiver.
-
In order that sounds transmitted or produced by the human voice or otherwise
through telephonic wires by means of the transmitting apparatus first described or
other means may be recorded in such form that they may be at any time subse-
quently reproduced at any distance I use a novel form of apparatus consisting of a
flat transparent disc of glass or other material which can readily be fitted up or
removed from an axis by which it can be made to revolve in suitable bearings
preferably, by means of clockwork or otherwise by which sufficient uniformity of
speed of revolution is obtained. I coat- one surface of this glass disc with a film
sufficiently sensitive to the action of light of the kind ordinarily known and used
in photographic processes, and the disc so prepared is then adjusted upon its axis
in a dark chamber. I arrange a very small aperture or lens, through which a
beam of light from any convenient source can be directed so that it falls upon the
sensitive surface and I make this aperture moveable in guides so that the beam of
light can be made to fall upon any point of the sensitive disc between its circum-
ference and its centre, and I connect the moveable aperture to the axis of the disc
in such manner that as the latter revolves the former also travels simultaneously
and the beam of light thus traces a spiral line upon the sensitive surface. I also
make the width of the aperture through which the beam of light passes variable by
means of an elastic or flexible or moveable shutter or diaphragm which is connected
to the disc or diaphragm-of-an-ordinary-telephonic-instrument in such manner-that.
every vibration of the telephonic diaphragm varies to a corresponding degree the.
width of the aperture. If therefore the telephonic diaphragm be made to vibrate
by the human voice or other sound directly or by the utterances of a receiver
telephonic instrument whilst the apparatus is in motion, a spiral line upon the
sensitive surface will be affected by the beam of light falling upon it and the width
of the spiral line so affected will vary in exact proportion with the character and
strength of each vibration.
The message to be recorded for reproduction having been thus impressed photo-
graphically upon the sensitized disc the latter is removed and the impression is.
developed and fixed in the usual well known way. This disc may then be kept.
until it is desired to transmit or reproduce the message recorded upon it and it is
then replaced upon its bearings and made-to revolve in the way already described,
whilst a strong beam of light is made to fall upon and follow the variable spiral.
line upon its surface and thence (after traversing the glass) upon a receiver of
selenium or other substance having the property of varying in its conductivity of
electricity in proportion to the degree of light to which it is exposed. This
selenium receiver is arranged to form part of an electrical wire circuit through
which a constant current of electricity can be made to pass, and in any desired part
of which one or more telephone receivers are situated; and in this way as the beam
of light falling upon the selenium receiver varies in proportion to the opacity,
thickness and width of the photographically deposited spiral line through which it
passes, so will corresponding undulations be produced in the electrical current
which undulations will be reproduced in the telephone receivers as audible sounds.
Figure 6 illustrates this arrangement.
a is a transparent glass disc mounted in bearings at 6 and made to revolve at a
uniform speed when desired. c is a guide in which moves the slide d having a
small aperture at e through which the beam of light is projected upon the plate a.
A shutter regulates the effective size of the aperture e and is itself regulated by
the diaphragm of a telephone instrument at g to which it is connected, and in which
the sounds to be recorded are produced by the voice or by a transmitting instru-
ment at any distance.
Instead of selenium, a disc of carbonized paper or of the materials hereinbefore
described in the former part of this specification may be used and such disc may
..

page_text: It is evident that the apparatus just described may be modified more or less in
its details. For instance the Telephone diaphragm which operates upon the variable
aperture through which the light passes may be stationary and the revolving disc
itself may be made to travel as it revolves so that a spiral line-upon its surface
may be affected by the light. A mirror, prism, lens, or other equivalent contrivance
actuated by the vibrating diaphragm may be used in order to vary the character of
the beam of light.
I sometimes use frictional electricity instead of electricity generated from a
galvanic battery in order to transmit messages through telephones of the kind
described. For this purpose I make the transmitting instrument of a disc of mica
coated with conducting material as already described to which disc electricity is
conveyed by a conducting wire from the receiver of any ordinary suitable frictional
electrical machine. This disc is adjusted in a suitable support parallel with and in
close proximity to a corresponding disc or block with which the insulated wire of
the telephone circuit is connected. The other end of the wire is connected with
a similar disc or block supported parallel with and in sufficiently close proximity to
a second telephone disc or diaphragm. When a charge of electricity is supplied
from the machine to the first or transmitting disc and the latter is made to vibrate
by the human voice or other sounds, corresponding undulations of electricity.are
caused in the wire of the circuit and in the second or receiving block the telephone
disc or diaphragm in proximity with which is attracted at each such undulation
and the sounds transmitted from the first disc are thus reproduced.
Figure 7 illustrates this arrangement. a is the first disc to which the electricity
from the machine passes by the wire b. The parallel disc or block c is connected
by the telephone wire d with the distant disc or block e parallel with the telephone
disc f.
When the telephonic signals or messages have to be transmitted by means of sub-
marine or other cables or wire in the immediate neighbourhood of other wires through
which electrical telegraph or other currents are also passing, it is necessary to prevent
as far as possible the effects of induction from such currents upon the telephone wire
in order that the messages transmitted by the latter may be audible and intelligible,
and for this purpose I arrange in a convenient situation near the end of such
submarine cable (assuming that a submarine cable is being used) an anti-inductive
apparatus consisting of a sufficient number of fine parallel insulated wires in the
neighbourhood of the telegraphic or other wires the inductive action of which upon
the telephone wire it is desired to neutralize.
The length and number of such fine wires are so proportioned that they are
equivalent in inducing power (electrically) to the wire in the submarine cable and
are proportioned to the length of the latter.
This anti-inductive apparatus is inserted in the telephone wire circuit its ends
being connected to the latter in such manner that any current passing through it
moves in the opposite direction to that passing through the cable itself and its end
connecting wires are brought round so as to be sufficiently removed from any
inductive action of the telegraph wires upon them.
Figure 8 is in illustration of the arrangement just described. a is the submarine
cable, b being a telephone wire, and c, c, telegraph wires. d is a parallel set of fine
wires in the neighbourhood of the wires c, c, inserted in the telephone wire bas
shewn, so that the current induced in them is in the opposite direction to that
induced in the telephone wire b in the cable a. By this arrangement any current
caused by inductive action upon the telephone wire in the cable is balanced by the
corresponding current induced in the latter in the opposite direction by the
inductive action of the telegraph wires upon the anti-inductive apparatus as
described.
Another part of my invention consists in a novel method of generating and
transmitting across the sea by electrical undulations corresponding audible tele-
phonic sounds,and, messages.
I take fines of dissimiler metal traversing the sea, to the water of which

page_text: they are exposed for a sufficient part of their length without being in contact with
each other: The ends of these wires are insulated, and at each end of the line.
suitable telephonic transinitting and receiving instruments are connected to them
in such manner that when the action of the sea water upon the dissimilar metals
generates galvanic electricity in them; the action of the telephonic transmitter at i
one end serves to draw off more or less of such electricity from the wires or cables
as the diaphragm vibrates, and so to deprive the station at the opposite end of
more or less current, these electrical variations being transformed in the usual way
into audible sonorous vibrations by the receiving instruments. It is evident that
this method of arrangement may be applied to telegraphs as well as telephones.
Having now described my invention and the manner in which it is to be
performed, I desire it to be understood that I am, well aware that materials have
before the date of my said Patent been carbonized in the presence of animal
charcoal for producing filaments or pieces of carbon for the purposes of electric
lighting, I therefore make no claim generally to such method of carbonizing any 1
such filaments, but what I do claim is :-
1. In an electric telephone transmitter the use of a resonant disc or plate of
carbonized materiál substantially as described.
2. For the purpose of constructing an electric telephone transmitter the manu-
facture of carbonized organic material in a suitable resonant form substantially as
described. .
3. The electric telephone transmitter herein before described consisting of the
resonant carbonized organic, material in combination with an electrical contact
piece or pieces of carbon or, metal or other conducting material lightly touching
such resonant carbonized organic material substantially as and for the purpose
herein before described.
4. The method of connecting a conducting wire to the resonant plate of
carbonized organic material by means of an electro-plated junction substantially as
described.
5. The novel forms of contact pieces suspended by a wire, thread, or string and
connected to the circuit by means of a thin wire so that such contact piece is free
to roll about easily when agitated and to present its curved surface to and in contact
with the carbonized vibratory disc as herein described and shewn.
6. The combination of two or more such contact pieces and suspending or attach-
ment wires or threads capable of rolling about on a carbonized vibratory disc or
plate with the electrical circuit as herein described and shewn.
7. The use in the construction of an electric. condenser_telephone receiver, of a
sufficient number of mica discs coated with a metal (preferably silver) by electro
deposition, substantially as herein before.described..
8. The combination in a recording telephone apparatus, of an acoustic diaphragm
with a moving sensitive photographic surface, the diaphragm determining and
controlling by its vibrations under the action of sounds impinging upon it the
extent, direction, intensity, or character of a beam of light which is projected upon
the said moving, sensitive photographic surface substantially in the manner and for
the purpose described and shewn in the drawing.
9. In a reproducing telephonic apparatus, the method substantially as herein-
before described of applying a beam of light projected upon, passing through and
varied by, the varying photographic imprint so produced upon such moving
sensitized surface, such beam of light afterwards actuating apparatus capable of
producing electrical disturbances by the varying action of light and in electrical
connection with which is a conducting wire having one or more telephones at any
desired position for the purpose of reproducing in the receiver telephone or
telephones the sounds by means of which the varying photographic imprint was
originally produced.
10. The combination and use of a frictional electrical machine with the vibrating
50

page_text: sound to a wire connected with a telephone receiving instrument all arranged and
operating substantially as described.
11. The construction and use of the anti induction apparatus for the purpose of
producing in the telephone line wire as nearly as possible perfect electrical
equilibrium substantially as described and shewn in the drawing.
12 The method of generating and utilizing electricity for the purpose of trans-
mitting audible messages by submarine wires, by means of conducting wires of
different metals exposed to the action of the sea for a sufficient part of their length,
substantially as described.
In witness whereof, I, the said Arthur French St. George, have hereunto set
my hand and seal this 20th day of August in the year of our Lord 1883.
ARTHUR FRENCH ST. GEORGE. (LS.)