IMPROVE- MENTS IN APPARATUS FOR TRANSMITTING AND RECEIVING AUDIBLE SIGNALS BY MEANS OF ELECTRICITY
Year: 1882

page_text: LETTERS PATENT to Arthur French St. George, of 40, Southampton Buildings,
Chancery Lane, in the County of Middlesex, for an Invention of "IMPROVE-
MENTS IN APPARATUS FOR TRANSMITTING AND RECEIVING AUDIBLE SIGNALS
BY MEANS OF ELECTRICITY."
PROVISIONAL SPECIFICATION left by the said Arthur French St. George
at the Office of the Commissioners of Patents on the 25th February 1882.
ARTHUR FRENCH ST: GEORGE of 40 Southampton Buildings, Chancery Lane,
in the County of Middlesex, "IMPROVEMENTS IN APPARATUS FOR TRANSMITTING
AND RECEIVING AUDIBLE SIGNALS BY MEANS OF ELECTRICITY
"
My present invention relates to apparatus used for the purpose of acoustical
electric telegraphy or telephony and it has for its objects novel methods of
construction and arrangement of such apparatus so that it is more simple and
effective and at the same time cheaper in manufacture and working than apparatus
for such purposes as heretofore ordinarily constructed and used.
The first part of my invention relates to novel methods of constructing and
arranging apparatus for the purpose of transmitting to a distance sounds consti-
tuting audible signals, through an ordinary electric conducting wire or wires
forming the circuit; and consists in the employment of iron or steel wire in such
apparatus and combining it with the circuit in such manner as to influence the latter
by inductive action or on the other hand in such manner that the circuit itself
shall influence the apparatus either directly or by induction. I arrange the iron
or steel wire in connection with a resonant surface of the kind hereinafter described
so that any sound, such for instance as the human voice, when made to impinge
upon the resonant surface causes the latter to vibrate in such manner in relation
to or in combination with the iron or steel conducting wire as to cause corre-
sponding electric currents or variations in the circuit and thus to produce
corresponding sounds at the place or places where they are to be received and
recorded. In order to put this part of my invention in operation I take a straight
or horseshoe shaped soft iron bar circular or of other suitable shape in cross section,
DO031

page_text: and upon its pole or poles I arrange a coil or coils of insulated wire in the usual
way. Opposite to the pole or poles of the bar upon which the coil or coils are
fitted as described and in close proximity, I adjust a coil or bundle of insulated
iron or steel conducting wire attached to or otherwise suitably connected with a
vibrating diaphragm of wood so that any vibratory motion imparted to such
diaphragm causes the coil of insulated iron or steel wire to move in a similar
manner or vice versa that any such movement imparted to the coil causes the
diaphragmn to move in a similar manner. The iron or steel wire coil may be either
attached rigidly directly to the diaphragm, or it may be connected to the latter
by one or more rigid bars or links or other connections.
Surrounding the coil of insulated iron or steel wire arranged as described, but
preferably in contact neither with the coil nor with the diaphragm, I arrange and
fix a second outer coil of insulated wire, which I prefer should also be iron or steel,
and through this outer coil I pass a constant local current of electricity from a
battery or other generator of any convenient kind.
The constant current of electricity thus passing through the outer coil produces
magnetic polarities in the various sections of the iron or steel wire which form the
inner coil and the latter is thus rendered extremely sensitive to inductive action
and capable of very rapid and clearly defined electric or magnetic pulsations or
variations when used for the purpose of electric telephony.
I sometimes also pass a constant local current of electricity through the inner coil
of insulated iron or steel wire from a battery or other suitable generator connected
to it in such manner as not to interfere with its vibrations. The current of
electricity so passing through it assists its magnetization and imparts a certain
amount of heat to the coil thus adding to its sensitiveness; and sometimes I connect
the inner coil with a suitable condensing apparatus of the ordinary kind, by which
the rapidity of working is increased. I prefer to make the coil or coils of insulated
wire surrounding the pole or poles of the soft iron bar as first described, of iron or
steel, and I connect them with the main line wire through which the pulsations
or variatious are transmitted which constitute the audible signals, either directly,
or with a separate wire circuit arranged in such a position as to be influenced
by the main line wire by induction. I prefer that the different coils of insulated
wire arranged as above described should be constructed in the method described
in the specification of former Letters Patent granted to me, dated August 27th
A.D. 1880 and numbered 3473, in which the coils of insulated wire are saturated
with melted paraffin wax shellac or other suitable insulating material or com-
position, so that the solid coil requires no bobbin to hold it intact. Instead of
making the straight or horseshoe shaped bar of soft iron as described, I sometimes
make it a permanent steel magnet. Or it may be of soft iron converted into an
electro magnet by electricity passing through a coil or coils of insulated wire
surrounding it. Sometimes I use the apparatus constructed and arranged as
described, but I omit the outer fixed coil of insulated wire; and sometimes I wind
both the inner and outer coils together so as to form a single coil, the insulated
wires either being laid parallel or being first twisted together.
Instead of one coil only of insulated iron or steel wire, attached or connected to
the vibrating diaphragm as described, I sometimes use two or more such coils upon
the surface of the diaphragm, and each such coil may have an outer coil round it,
or a double coil with the insulated wires wound upon it as last described, and one
or more soft iron bars or magnets with their coils may be used in conjunction with
such diaphragm coils.
And sometimes instead of the soft iron bar surrounded with a coil or coils I use
a fixed coil of insulated iron or steel conducting wire arranged opposite to the coil
attached to the diaphragm as described, and an outer coil may be arranged round
either or both such coils so as to magnetize in the way already hereinbefore
described either the fixed coil or the vibrating diaphragm coil or both. And either
one or more such stationary coils may be used in conjunction with one or more
coils attached to the diaphragm, and one or more of such diaphragm coils may

page_text: have an outer coil or coils to magnetize it or them; or one or more of the stationary
or fixed coils may have an outer coil or coils to magnetize it or them. The wires
of the different coils so used may be arranged so as to form double coils as already
described, the wires being wound either parallel or first twisted together.
Sometimes I insert the fixed coil, used as described in the place of the soft iron
bar, either directly, in the main line wire circuit, or in a circuit influenced by or
influencing the main line wire by induction; and sometimes instead of or in
combination with such method of arrangement, I connect the outer coil of such
fixed coils with the main line wire in a similar inanner. Or, sometimes I surround
both the single fixed coil and the coil attached to the diaphragm, with a single
separate coil of insulated wire. Or, sometimes I connect the coil attached to the
diaphragm, to the main line wire, or, to a wire influencing or influenced by the
main line wire by induction. 1 make the diaphragm preferably of wood, but I
sometimes make it of other non-metallic body capable of sufficient audible
vibration; or in some cases, and in some of the methods of arrangement described
it may be made of metal, such as iron or steel. Another part of my invention
consists of novel methods of constructing and arranging apparatus by means of
which electrical currents or variations are transmitted so as to produce audible
signals by means of corresponding sounds, such as the human voice, acting upon
the apparatus.
Electrical currents or variations so produced in the novel apparatus which I will
now describe are converted, after passing along the main line wire curcuit, into
audible signals by means of the novel apparatus already described or other suitable
apparatus of the kinds already known and used. For the purpose of so transinitting
electrical currents or variations, I employ pieces of semi-conducting material such
as carbon through which the currents pass and are made to vary by means of the
vibration of such pieces induced by sound, as in the apparatus wellknown as the
microphone. I take one or preferably more bars or pieces of such semi-conducting
material, preferably carbon, and I make some or all of such pieces hollow so that
each contains within it a column or body of air, and I arrange these pieces parallel
or in other convenient positions relatively to each other and loosely supported at
the ends in carbon or other blocks connected with the wire circuit in which the
currents or variations are to be produced in such manner that the hollow bars
form part of the circuit.
Opposite to the open ends of the hollow bars so arranged is a column or columns
of air confined in corresponding tubes or passages, in a suitably shaped mouthpiece
at the outer end of which the sound such as the human voice is inade by which
the electrical currents or variations are to be produced. When such sounds are
made into or in the neighbourhood of the mouthpiece, the column or columns of
air confined in the latter as described are set in vibration, which vibration is com-
municated directly to the corresponding columns of air in the hollow carbon bars,
and the latter are themselves made to vibrate in their supports and thus to cause
corresponding currents or variations in the electricity passing from any suitable
battery or generator through the carbon bars and through the wire circuit with
which the latter are in connection.
The outer end of the hollow carbon bars may be closed, In order to increase the
capacity of the apparatus just described or other transmitting apparatus to over-
come the resistance of the main line wire in which electrical currents or variations
are to be produced and also the effectiveness of the receiving apparatus, and
through which it is often found necessary or advisable to maintain a constant
current of electricity from a battery or other generator, which current passes
through coils in the receiving apparatus for the purpose of producing magnetism,
instead of using a single induction apparatus I arrange the transmitting apparatus
in connection with a constant current of Electricity passing through the primary coil
of each or all of two or more such induction coils arranged separately or conjointly;
and I connect the secondary or other coils surrounding them all or some in parallel
circuit with each other, and these coils arranged in parallel circuits I insert in the

page_text: main line wire in which I desire to induce currents by the action of the primary
wires.
Another part of my invention consists in imbedding a wire or other electrical
conductor or semi-conductor in a solid material, so that the heat produced in such
conductor by the passage of a current of electricity expands it, and such expansions
produce molecular or mechanical vibrations in the solid material. I prefer to
employ a disc or diaphragm of glass, shellac, or other suitable material into which
I embed a metallic wire or other electrical conductor or semi-conductor, leaving its
extremities protruding so that they can be connected to an electrical telegraph or
telephone circuit. Sometimes I connect the solid material in which the conductor
is embedded as described to a resonant vibrating surface such as a diaphragm.
Currents of electricity corresponding in character to sonorous vibrations will
reproduce corresponding sonorous vibrations in apparatus constructed as described.
In the wellknown arrangement of apparatus known as an electric condenser,
audible sonorous vibrations can be produced by charging the condenser with a
charge of electricity, and another part of my invention consists in novel apparatus
for utilizing every molecular or mechanical movement in such condenser so that
it may be used as a receiver by which articulate speech as well as other sounds
may be produced.
For this purpose I embed in a suitable solid material a sufficient number of
electrical conductors arranged in relation to each other in the same way as in an
ordinary electrical condenser. One series of such conductors constitutes one pole
or side of the condenser, and the other series the other side or pole. When the
condenser so constructed receives a charge of electricity the solid material is
polarized, and a strain or vibration is produced throughout the whole mass, the
vibrations being distinctly audible. The solid material must be an insulating
substance of great electrical resistance, and I prefer to employ a disc of glass, shellac,
or other suitable material in which the conductors are embedded as in the form of
apparatus last herein before described.

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 25th August 1882.
ARTHUR FRENCH ST. GEORGE of 40, Southampton Buildings, in the County
of Middlesex "IMPROVEMENTS IN APPARATUS FOR TRANSMITTING AND RECEIVING
AUDIBLE SIGNALS BY MEANS OF ELECTRICITY
"
My present invention relates to apparatus used for the the purpose of acoustical
electrical telegraphy or telephoney, and it has for its objects novel method of
construction and arrangement of such apparatus so that it is more simple, effective,
and cheaper in manufacture and working than apparatus for such purpose as
heretofore ordinarily constructed and used.
The first part of my invention relates to novel methods of constructing and
arranging apparatus for the purpose of transmitting to a distance sounds con-
stituting audible signals, through an ordinary electric conducting wire or wires
forming the circuit; and consists in the employment of iron or steel wire in such
apparatus and combining it with the circuit in such manner as to influence the
latter by inductive action, or on the other hand in such manner that the circuit
itself shall influence the apparatus either directly or by induction. I arrange the
iron or steel wire in connection with a resonant of the kind hereinafter described
so that any sound, such for instance as the human voice, when made to impinge
upon the resonant surface causes the latter to vibrate in such manner in relation
to or in combination with the iron or steel conducting wire as to cause correspond-
ing electric currents or variations in the circuit and thus to produce corresponding
sounds at the place or places where they are to be received and recorded.
In order to put this part of my invention in operation I take a straight or horse-
shoe-shaped soft iron bar circular or of other suitable shape in cross section, and
upon its pole or poles I arrange a coil or coils of insulated wire in the usual way.
Opposite to the pole or poles of the bar upon which the coil or coils are fitted as
described and in close proximity, I adjust a coil or bundle of insulated iron or steel
conducting wire attached to or otherwise suitably connected with a vibratind
diaphragm of wood so that any vibrating motion imparted to such diaphragm
causes the coil of insulated iron or steel wire to move in a similar manner, or vice
versa that any such movement imparted to the coil causes the diaphragm to move
in a similar manner. The iron or steel wire coil may be either attached rigidly
itself to the diaphragm, or it may be connected rigidly to the latter by one or
more bars or links or other connections. Surrounding the coil of insulated iron or
steel wire arranged as described, but preferably in contact neither with the coil
nor with the diaphragm, I sometimes arrange and fix a second outer coil of
insulated wire, which I prefer should also be of iron or steel, and through this
outer coil I pass a constant local current from a battery or other generator of any
convenient kind. The constant current of electricity thus passing through the
outer coil produces magnetic polarities in the various sections of the iron or steel
wire which forın the inner coil and the latter is thus rendered more sensitive to
inductive acction and capable of very rapid and clearly defined electric or magnetic
polarities or variations when used for the purpose of electric telephony. I some-
times also pass a constant local current of electricity through the inner coil of
insulated iron or steel wire from a battery or other suitable generator connected to
it in such inanner as not to interfere with its vibrations. The current of
electricity so passing through it assists its magnetization and imparts a certain

page_text: amount of heat to the coil thus adding to its sensitiveness, and sometimes I connect
the inner coil with a suitable condensing apparatus of the ordinary kind, by
which the rapidity of working is increased. I prefer to make the coil or coils of
insulated wire surrounding the pole or poles of the soft iron bar as first described,
of iron or steel, and I connect them with the main line wire through which the
pulsations or variations are transmitted which constitute the audible signals, either
directly, or with a separate wire circuit influenced by the main line wire by
induction. I prefer that the different coils of insulated wire arranged as described
should be constructed in the method described in the specification of former
Letters Patent granted to me, dated August 27th A.D. 1880, and numbered 3473,
in which the coils of insulated wire are saturated with melted paraffin wax, shellac,
or other suitable insulating material or composition, so that the solid coil requires
no bobbin to hold it intact. Instead of making the straight or horse-shoe-shaped
bar of soft iron, I sometimes make it a permanent steel magnet. Or it may be of
soft iron converted into an electro magnet by electricity passing through a coil or
coils of insulated wire surrounding it. Sometimes I use the apparatus constructed
and arranged as described, but I omit the outer fixed coil of insulated wire ;
and sometimes I wind both the inner and outer coils together so as to form a
single coil, the insulated wires either being laid parallel or being first twisted
together. Instead of one coil only of insulated iron or steel wire, attached or
.connected to the vibrating diaphragm as described, I sometimes use two or more
such coils upon the surface of the diaphragm, and each such coil may have an
outer coil round it, or a durable coil with the insulated wires wound upon it as
last described, and one or more soft iron bars or magnets with their coils may be
used in conjunction with such diaphragm coils. And sometimes instead of the soft
iron bar surrounded with a coil or coils, I use a fixed coil of insulated iron or steel
conducting wire arranged opposite to the coil attached to the diaphragm as
described, and an outer coil may be arranged round either or both such coils so as
to magnetize in the way already described either the fixed coil or the vibrating
diaphragm coil or both.
'
And either one or more such stationary coils may be used in conjunction with
one or more coils attached to the diaphragın, and one or more of such diaphragm
coils may have an outer coil or coils to magnetize it or them; or one or more of
the stationary or fixed coils may have an outer coil or coils to magnetize it or
them. The wires of the different coils so used may be arranged so as to form
double coils as already described, the wires being wound either parallel or first
twisted together. I sometimes insert the fixed coil, used as described in the place
of the soft iron bar, either directly in the main line wire circuit, or in a circuit
influenced by, or influencing, the main line wire by induction; and sometimes
instead of or in combination with such method of arrangement, I connect the
outer coil of such fixed coil with the main line wire in a similar manner. Or,
sometimes I surround both the single fixed coil and the coil attached to the
diaphragm, with a single separate coil of insulated wire. Or, sometimes I connect
the coil attached to the diaphragm to the main line wire, or to a wire influencing
or influenced by the main line wire by induction. I make the diaphragm
preferably of wood, but I sometimes make it of other non-metallic body capable
of sufficient audible vibration; or, in some cases, and in some of the methods of
arrangements described, it may be made of metal, such as iron or steel. The
accompanying drawings is in illustration of one of the forms of arrangement
described. Figure 1 is a longitudinal section, and figure 2 a front view of the
apparatus. a is the bar having its end surrounded with the coil of insulated
wire b. The wooden diaphragm c has a coil of insulated wire d fixed to its
centre.
Another part of my Invention consists of novel methods of constructing and
arranging apparatus by means of which electrical currents or variations as trans-
mitted so as to produce audible signals by means of corresponding sounds, such as
the human voice, acting upon the apparatus. Electrical currents or variations so

page_text: produced in the novel apparatus which I will now describe, are converted, after
passing along the main line wire circuit, into audible signals by means of the
novel apparatus already described or other suitable apparatus of the kinds already
known and used. For the purpose of so transmitting electrical currents or
variations, I employ pieces of semi-conducting material such as carbon through
which the currents pass and are made to vary by means of the vibration of such
pieces induced by sound, as in the apparatus well known as the microphone. I
take one or preferably more bars or pieces of such semi-conducting material,
preferably carbon, and I make some or all of such pieces hollow so that each
contains within it a column or body of air, and I arrange these pieces parallel or
in other convenient position relatively to each other and loosely supported at their
ends in carbon or other blocks connected with the wire circuit in which the
currents or variations are to be produced, in such manner that the hollow bars
form part of the circuit. Opposite to the open ends of the hollow bars so arranged
is a column or columns of air confined in corresponding tubes or passages in a
suitably-shaped mouthpiece at the outer end of which the sound, such as the human
voice, is made by which the electrical currents or variations are to be produced. When
such sounds are made into or in the neighbourhood of the mouthpiece, the column or
columns of air confined in the latter are set in vibration, which vibration is communi-
cated directly to the corresponding columns of air in the hollow carbon bars, and
the latter are themselves made to vibrate in their supports and thus to cause
corresponding currents or variations in the electricity passing from any suitable
battery or generator through the carbon bars and through the wire circuit with which
the latter are in connection. The outer ends of the hollow carbon bars may be
closed. In order to increase the capacity of the apparatus just described or other
transmitting apparatus to overcome the resistance of the main line wire in which
electrical currents or variations are to be produced and also the the effectiveness of
the receiving apparatus, and through which it is often found necessary or advisable to
maintain a constant current of electricity from a battery or other generator, which
current passes through coils in the receiving apparatus for the purpose of producing
magnetism, instead of using a single induction apparatus I arrange the transmitting
apparatus in connection with a constant current of electricity passing through the
primary coil of each or all of two or more such induction coils arranged separately
or conjointly; and I connect the secondary or other coils surrounding them, all or
some, in parallel circuit with each other, and these coils arranged in parallel circuits
I insert in the inain line wire in which I desire to induce currents by the action of
the primary wires.
Another part of my Invention consists in embedding a wire or electrical
conductor or semi-conductor in a solid material, so that the heat produced in such
conductor by the passage of a current of electricity expands it, and such expansions
produce molecular or mechanical vibrations in the solid material. I prefer to
employ a disc or diaphragm of glass, shellac, or other suitable material into which
I embed a metallic wire or other electrical conductor or semi-conductor, leaving its
extremities protruding so that they can be connected to an electrical telegraph or
telephone circuit. Sometimes I connect the solid material in which the conductor
is embedded as described to a resonant vibrating surface such as a diaphragm.
Currents of electricity corresponding in character to sonorous vibrations will
reproduce corresponding sonorous vibrations in apparatus constructed as described.
In the well known arrangement of apparatus known as an electric condenser,
audible sonorous vibrations can be produced by charging the condenser with a
charge of electricity, and another proof of my invention consists in novel apparatus
for utilizing every molecular or mechanical movement in such condenser, so that it
may be used as a receiver by which articulate speech as well as other sonnds may
be produced. For this purpose I embed in a suitable solid material a sufficient
number of electrical conductors arranged in relation to each other in the same way
way as in an ordinary electrical condenser. One series of such conductors constitutes
one pole or side of the condenser, and the other series the other sido or pole. When

page_text: the condenser so constructed receives a charge of electricity the solid material is
polarized, and a strain or vibration is produced throughout the whole mass, the
vibration being distinctly audible. The solid material must be an insulating
substance of great electrical resistance, and I prefer to employ a disc of glass,
shellac, or other suitable material, in which the conductors are embedded as in the
form of apparatus last herein before described. Having now described my invention
and the manner in which it is to be performed, I claim :-
1. In an electric telephone (answering the purpose either of a receiver or
transmitter) the combination of a resonant surface, preferably or thin disc of wood,
and a coil or bundle of iron or steel wire, preferably insulated, attached or suitably
connected thereto, with a soft iron bar upon which is wound a coil of insulated
wire connected to an electric circuit directly, or indirectly by means of induction
apparatus; the coil of iron or steel wire attached to the resonant surface being in
no case included in the main line circuit or in a circuit influenced by or influencing
the main line circuit. 2. In an electric telephone (transmitters or receiver) the
combination of a resonant surface and coil or bundle of iron or steel wire attached
or connected thereto with a soft iron bar upon which are wound two or more coils,
each or either of which coils may consist of two or more wires wound together
parallel or twisted, substantially as described.
3. The use of iron or steel wire wound round a soft iron bar or bundle or coil
of iron wire or round a permanently magnetic steel bar or electric magnet, for the
purpose of constructing an electric telephone receiver or transmitter.
4. In an electric telephone (receiver or transmitter) the combination of a
resonant surface and coil or bundle of iron or steel wire attached or connected
thereto with a permanently magnetic steel bar having one or more coils of wire
wound round it, each or either of which coils may consist of two or more wires
wound together parallel or twisted, substantially as described.
5. In an electric telephone (transmitter or receiver) the combination of a
resonant surface and coil or bundle of iron or steel wire attached or connected
thereto with a coil enveloping the coil or bundle of iron or steel wire on the
resonant surface and preferably not in electrical or mechanical contact with it.
6. In an electric telephone (transmitter or receiver) the combination of a
resonant surface and coil or bundle of iron or steel wire attached or connected
thereto and enveloped by a coil (as in claim 5) with a soft iron bar and its coil or
coils (as in claims 1, 2, 3, 4, and 5) or with a permanently magnetic steel bar (as
in claims 1, 2, 3, 4, and 5.
7. In the apparatus described in claims 1, 2, 3, 4, 5, and 6, the use in place of
the soft iron bar, of a bundle of soft iron wires or a bundle of permanently magnetic
steel wires or bars, forming the core of the coil or coils which are adjusted
opposite to the coil carried by the resonant surface, substantially as described.
8. In an electric telephone transmitter, the use of hollow microphone contact
pieces arranged in suitable sockets of bad contact conducting or semi-conducting
material, each or either of such hollow contact pieces having an air-containing
cavity, connected with a main body of air set in vibration by means of sound
waves made to impinge upon such body of air contained preferably within the
cavity of a mouthpiece, such mouthpiece being preferably divided into several
channels or passages in close proximity to the air-containing cavity of each contact
piece, substantially as and for the purpose described.
9. In an electric telephone receiver, the use of a resonant surface, preferably a
thin disc of glass or shellac, into which is embedded a metallic wire or wires or
other electrical conductor or semi-conductor connected directly or indirectly with
an electric wire or with a complete circuit, so that any electrical or magnetic
variations occurring in the electric wire or circuit with which the apparatus is con-
nected causes mechanical or molecular vibrations in the embedded conductor or
conductors, setting the resonant surface in audible vibration, substantially as
described.
10. The use of the apparatus described in claim 9, with the embedded conductors

page_text: arranged in relation to each other in the manner of an electric condenser, one set
of conductors being embedded in very close proximity to another set of similarly
embedded conductors, so that a charge of electricity communicated to one set will
induce in the other set of conductors a charge of opposite polarity, the action of
such electrical influences being to produce audible vibrations of the resonant
surface, substantially as described.
11. The combination of two or more such resonant surfaces arranged parallel to
and in close proximity to each other.
In witness whereof I the said Arthur French St. George have hereunto set my
hand and seal this 25th day of August in the year of Lord 1882.
A DITUTID EDENOU