IMPROVEMENTS IN TELEGRAPHY
Year: 1881

page_text: LETTERS PATENT to Sydney Pitt, of Sutton, in the County of Surrey, for
an Invention of "IMPROVEMENTS IN TELEGRAPHY." A communication from
abroad by Orazio Lugo, M.D., of the City, County, and State of New York,
in the United States of America.
PROVISIONAL SPECIFICATION left by the said Sydney Pitt at the Office
of the Commissioners of Patents on the 15th March 1881.
SYDNEY PITT, of Sutton, in the County of Surrey. "IMPROVEMENTS IN
TELEGRAPHY." [A communication from abroad by Orazio Lugo, M.D., of the
City, County, and State of New York, in the United States of America.]
The first part of the Invention relates to electric circuits for telephonic or
telegraphic transmission, and the improvement consists in a novel organization of
the conductors composing said circuits, whereby interference arising from action
and reaction upon each other of derived or induced currents is prevented.
Telephonic or telegraphic circuits, as is well known, consist in part of a conductor
of electricity extending from one station to the other, and insulated from all
surrounding conducting bodies, including the earth, the circuit being completed
either through the earth or through a return conductor, which may or may not be
insulated from the earth, but must be insulated from the first mentioned conductor
which forms a part of the same circuit. In overland lines the conductors are
usually suspended at a considerable height above the ground, and are insulated
therefrom and from the various surrounding objects by means of the intervening
air, which is an almost absolute non-conductor of electricity. The conductors are
insulated from their supports by means of glass or other suitable non-conductor.
Subterranean or submarine conductors are insulated by enveloping them in one
or more coatings of non-conducting material, usually gutta percha or paraffine,
enclosed in a lead or iron pipe or armor.
When a pulsation of electricity is transmitted through a conductor insulated in
the manner above described, a peculiar phenomenon, termed electro static induction,
takes place, which is the inevitable accompaniment of the beginning or ending, the
increase or decrease, of the electric current.

page_text: Any conductor through which electric currents flow is necessarily partially or
wholly surrounded by other conductors in which induced currents are thus generated.
If the whole or a considerable portion of a circuit of conductors of small electrical
resistance is very near to a conductor which is traversed by an inducing current,
and is so situated with reference thereto that the induction tends to occur throughout
in one direction, the induced current will be very considerable, and its reaction
upon the inducing current will also be proportionately great. The effect of this
reaction is to diminish for the time being the strength of the inducing current. If
on the other hand the circuit in which the induced current flows is situated at a
considerable distance from the conductor traversed by the inducing current, or if it
is only exposed to inductive action for a small portion of its length, or is so situated
that the induced current tends to flow in opposite directions in different portions
of the circuit, then the induced current will be small and its reaction upon the
inducing current will also be small. These well known effects of inductive action
constitute very serious obstructions to the efficient transmission of telegraphic or
telephonic signals, especially in circuits of considerable length.
For example, when a conductor is placed within an insulating coating, and is
laid under ground or under water, the surrounding earth or water constitues a
conductor in which an inductive action is set up, which in turn reacts upon the
original current and renders the signals indistinct or confused, the general tendency
being to prolong all signals and to obliterate the intervals between successive
signals. When two or more such insulated conductors are enclosed within a single
conduit, or otherwise placed parallel and in close proximity to each other, the
inductive action of the current in each conductor tends to induce correlative
currents simultaneously in all the other parallel conductors, and thus interfere with
the correct transmission of signals through them.
When the electric telephone is used as a medium of communication this effect
becomes especially troublesome, for the reason that communications transmitted
through any one of the groups of conductors may distinctly be heard in an
instrument attached to any one of the other conductors. Various attempts
heretofore have been made to obviate this difficulty, one of which attempts
consisted in using two insulated conductors parallel to each other, one for the
direct and the other for the return conductor of the circuit, this organization being
based upon the theory that the inductive action of one conductor would be
counteracted by equal and opposite action of like character in the other conductor.
Although the effects of inductive action are somewhat diminished under this
arrangement they are by no means effectually eliminated, inasmuch as two parallel
conductors cannot be so arranged in practice that each can be situated at precisely
the same mean distance from all neighboring conductors, from which it results
that the inductive action in one portion of a conductor cannot accurately be
compensated by the opposite effect in another portion of the other conductor.
The Invention is based upon the discovery that if one portion of a circuit be
surrounded by the other helically, one portion passing through the mathematical
axis of the other, and being properly insulated therefrom, thus forming a solenoid,
and either portion be used for the direct and the other portion for the return
conductor of a telegraphic or telephonic circuit of any length, induced, derived, or
magnetizing currents will be entirely prevented.
In the accompanying Drawings,
Figure 1 represents the two portions of a telegraphic or telephonic circuit
organized in accordance with the principles of the Invention.
.use.
Figure 2 shows a modification of the same, which is more suitable for practical
Figure 3 is a theoretical diagram illustrating the application of the Invention to
a telegraphic circuit, and Figure 4 in like manner represents its application to a
telephonic circuit.
Two metallic conductors A, B, are shown in Figure 1 as enveloped in the ordinary
manner in insulating coatings a, b, of suitable material, the insulated conductor B

page_text: being wound helically and as closely as possible around the conductor A, as shown
at O. When the ends of the conductor are united they form a solenoid.
I make use of the double conductor constructed as above described of any
desired length for a telegraphic or telephonic circuit. It will be evident upon
inspection that the mean distance of the conductors A, B, from each other will be
the same throughout the entire circuit, and it will also be observed that the mean
distance of the conductors from all surrounding objects of whatsoever nature, and
It follows
of whatsoever actual distance therefrom, will be precisely the same.
therefore that as the current in traversing the circuit] necessarily flows helically in
a given direction through one conductor, and directly in the opposite direction
from the other conductor, the inductive effect of the current in each conductor,
while of opposite character, will be precisely equal in amount.
It is obvious that under the organization herein before described the length of the
helical conductor necessarily greatly exceeds that of the other, consequently where
of equal conductivity per unit of length the total resistance of the helical conductor
would necessarily be much greater than that of the direct one. Even under these
conditions the Invention will be operative, and induction will be prevented, but it
is preferred to have the two conductors of equal resistance.
The resistance of the two conductors could obviously be modified by making the
helical one of much larger wire than the other, but such a mode of construction is
obviously objectionable for mechanical reasons.
This objection is obviated by constructing the improved conductor in the manner
shown in Figure 2, which represents the direct conductor A. as enveloped in a
compound helix consisting of several parallel conductors 1, 2, 3, 4, which number
has been found to be a convenient one in practice, which conductors are of such
thickness and electrical conductivity as to render their joint resistance per unit of
conductivity measured on the direct conductor approximately the same as that of
that conductor itself.
Figure 3 represents an organization of telegraph apparatus which is preferred,
which Figure shows a battery E, a transmitting key K, a direct axial or central
conductor A connecting the key with the receiving instrument R, and four helical
conductors 1, 2, 3, 4, connected in multiple- arc with the battery and receiver
respectively. This organization of apparatus constitutes what would be called by
analogy in other forms of telegraphy a metallic circuit, either open or closed,
according to the normal position of the transmitting key.
It is obvious that in apparatus thus organized electric currents or pulsations
transmitted through one conductor will return through the other, and that the
inductive influence of the two sets of conductors both upon each other and upon
all surrounding objects will be equal and opposite. It follows, therefore, that any
inductive effects of whatever nature produced in or by the direct conductor will be
neutralized by similar effects produced in the return conductor.
Figure 4 illustrates a circuit equipped with speaking telephones C, C, arranged
upon the same principle as that hereinbefore described. The telephones act both
as receivers and transmitters, the circuit necessarily passing through them.
Any required number of independent circuits of conductors organized as above
described may lie parallel and close together within a single conduit or pipe, and
each conductor will be absolutely protected against the effects of induction both in
itself and in the neighboring conductors whatever their number or relative
position. I am thus enabled to employ one circuit to convey a portion of the
current generated by a dynamo electric machine and employed to transmit power
or to supply a series of electric lamps and to use another circuit for ordinary
commercial telegraphy under either the Morse, the duplex, the quadruplex, or the
automatic system of transmission, while still another circuit may be employed for
oral transmission by means of speaking telephones, and any number of such circuits
may be enclosed in a single casing without in the slightest degree interfering with
each other.
The objects of the next part of the Invention are so to organize the apparatus

page_text: that any desired number of intermediate stations may be employed besides the
terminal ones, and that were a number or series of helical conductors constitute a
part of the circuit each one of them may be utilized for work independently of the
others, so that currents of different character may simultaneously be sent through
the same compound conductor, that is, to say, one conductor may be employed for
the transmission of dynamo-electric currents, another for battery currents, and
another for telephonic transmission.
The Invention contemplates the employment of the most approved apparatus of
the present day, but as the details of such apparatus are well understood they need
no description here.
Figures 5 and 6 of the accompanying Drawings show these organizations arranged
in the best way now known to me, but the arrangement of apparatus may be
varied in well-known ways without departing from the principle of the Invention,
the distinguishing characteristic of which is the transmission of all the currents,
impulses, or pulsations, in one direction through a conductor constituting the
longitudinal axis of a solenoid, and in the other through a series of conductors,
coiled helically around said direct conductor, their circuits, of course, passing
through the generator and receiving and transmitting apparatus. The conductors,
it will be understood, are properly insulated from each other, and are adapted for
submarine or subterranean uses by being armored or enclosed in conduits or pipes
in well known ways.
Figure 5 represents a theoretical diagram of the improved apparatus organized
for the transmission of both voltaic and magneto currents, with a portion of the
apparatus at each station constituting a part of the direct conductor and other
portions constituting parts of the helical conductor, the helical conductors in this
Figure being shown as united in multiple arc at their terminals so as to constitute
in effect but one conductor.
Figure 6 represents a similar diagram, showing the apparatus as organized for
the transmission of dynamo electric, galvanic, and magneto currents, with
generating, receiving, and transmitting apparatus interposed in the helical circuits,
and with each of the helical conductors organized for the transmission of currents
or pulsations differing in character from the others.
These Drawings each show two terminal stations and one intermediate station,
which is sufficient for the purpose of illustration, but obviously the number of
intermediate stations may be varied to any desired extent.
Under the organization shown in Figure 5 the apparatus employed at each of
the terminal stations U, W, is as follows:-
The direct conductor A is enveloped by the helical conductor B, both being
properly insulated. A battery E at each station is connected by a wire e with a
Morse key K, a wire f being connected with the helix of an ordinary relay R
provided with a local battery L and with a sounder S. A switch 8 connects the
helix of each receiver with the direct conductor A above mentioned.
At the intermediate station V, a corresponding switch a connects the direct
conductor with the helix of the receiver R, provided with its local battery L, and
sounder S. The wire of this helix passes through a transmitting key K,
connected by the direct conductor A with the terminal station W, as already
described.
The switch 8 can be turned so as to connect directly with the rheostat H, and
cut out the relay R, and sounder S, as will be readily understood from the
Drawing, the rheostat affording means of compensating disturbances caused by
cutting the relay and sounder into or out of circuit. An ordinary microphone
transmitter T and its local battery L', are shown as included at each station in
circuit with a receiving telephone C. At the terminal stations U, W, this circuit
starts from the switch point h through the wires i, and through the telephones to
the point j, where it connects with the helical conductors 1, 2, 3, 4, in multiple arc.
The switches afford a means of cutting the relays, keys, and battery out of circuit,

page_text: leaving the direct conductor A. short circuiting the relay in a way which will be
obvious from an inspection of the Drawings.
The telephone circuit at station V is provided with a rheostat h¹ to enable its
resistance to be adjusted relatively to that of the direct conductor. The switch s
in the helical conductor enables the current to be switched from the telephone
circuit to the shunt wire g, thus enabling the operator to cut out the telephone at
the intermediate station when desired. This shunt wire connects with the helical
conductors at a point beyond the intermediate station, which conductors are again
connected in multiple arc at their terminal stations in a manner similar to that
above described. It will thus be seen that under the organization shown, the
direct conductor may be utilized for the transmission of galvanic or voltaic currents
or pulsations, and that the helical conductor may be used for telephonic_trans-
mission, one or the other being thrown out of circuit by the switches as desired.
It is also obvious that this arrangement could be reversed. Of course both sets of
apparatus cannot be used at the same time as a telephone and as a telegraph,
but the telephone receiver could be made to act as a telegraph receiver, either
alone or at the same time that the relay and sounder are operating on the direct
conductor.
The following is a description of the apparatus shown in Figure 6, that at each
terminal station X, Z, being alike.
The direct conductor A extends from station to station without a break, while
each of the helical conductors 1, 2, 3, are connected with a different generator,
transmitter, and receiver at each station. For instance the solid black lines show
the direct conductor A as connected by a wire 1 with a key K, battery M, and
sounder S at each terminal station, and with a corresponding key and sounder at
the intermediate station, this conductor being marked 1. The helical conductor 2
is shown in long dotted lines as connected through a dynamo electric machine or
generator G at the terminal stations, and with a key K and sounder S¹ at each
station. The third helical conductor 3 is shown in short broken lines as connected
in circuit with ordinary magneto telephones C at each station. The terminals of
all these helical conductors are connected in multiple are with the direct conductor,
thus forming metallic circuits normally open or closed according to the position of
the keys.
Under the above organization, it is not essential that the resistance of the
various conductors should be exactly equal or balanced, but the apparatus on the
contrary will work with quite a wide range of adjustment.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Sydney Pitt in the Great Seal Patent Office on the
15th September 1881.
SYDNEY PITT, of Sutton, in the County of Surrey.
"IMPROVEMENTS IN
TELEGRAPHY." A communication from abroad by Orazio Lugo, M.D., of the
City, County, and State of New York, in the United States of America.
The first part of the Invention relates to electrical circuits for telephonic or
telegraphic transmission, and the improvement consists in a novel organization of
the conductors composing said circuits, whereby interference arising from action and
reaction upon each other of derived or induced currents is prevented.
Telephonic or telegraphic circuits, as is well known, consist in part of a conductor
of electricity extending from one station to the other and insulated from all
surrounding conducting bodies, including the earth, the circuit being completed
either through the earth, or through a return conductor which may or may not be
insulated from the earth, but must be insulated from the first mentioned conductor
which forms a part of the same circuit. In overland lines the conductors are usually
suspended at a considerable height above the ground, and are insulated therefrom
and from the various surrounding objects by means of the intervening air which is
an almost absolute non-conductor of electricity. The conductors are insulated from
their supports by means of glass or other suitable non-conductor.
Subterranean or submarine conductors are insulated by enveloping them in one
or more coatings of non-conducting material, usually gutta percha or paraffin,
enclosed in a lead or iron pipe or armor.
When a pulsation of electricity is transmitted through a conductor insulated in
the manner above described, a peculiar phenomenon, termed electro-static induction,
takes place, which is the inevitable accompaniment of the beginning or ending, the
increase or decrease, of the electric current.
Any conductor through which electric currents flow is necessarily partially or
wholly surrounded by other conductors in which induced currents are thus
generated. If the whole or a considerable portion of a circuit of conductors of
small electrical resistance is very near to a conductor which is traversed by an
inducing current, and is so situated with reference thereto that the induction tends
to occur throughout in one direction the induced current will be very considerable,
and its reaction upon the inducing current will also be proportionately great. The
effect of this reaction is to diminish for the time being the strength of the inducing
current. If on the other hand the circuit in which the induced current flows is
situated at a considerable distance from the conductor traversed by the inducing
current, or if it is only exposed to inductive action for a small portion of its length,
or is so situated that the induced current tends to flow in opposite directions in
different portions of the circuit, then the induced current will be small, and its
reaction upon the inducing current will also be small. These well known effects of
inductive action constitute very serious obstructions to the efficient transmission of
telegraphic or telephonic signale, especially in circuits of considerable length. For
example, when a conductor is placed within an insulating coating, and is laid under
ground or under water, the surrounding earth or water constitutes a conductor in
which an inductive action is set up, which in turn reacts upon the original current,
and renders the signals indistinct or confused, the general tendency being to prolong
all signals, and to obliterate the intervals between successive signals. When two or
more such insulated conductors are enclosed within a single conduit, or otherwise
placed parallel and in close proximity to each other, the inductive action of the
current in each conductor tends to induce correlative currents simultaneously in all
the other parallel conductors, and thus interfere with the correct transmission of
signals through them.
When the electric telephone is used as a medium of communication, this effect
becomes especially troublesome, for the reason that communications transmitted

page_text: through any one of the groups of conductors may distinctly be heard in an
instrument attached to any one of the other conductors. Various attempts
heretofore have been made to obviate this difficulty, one of which attempts con-
sisted in using two insulated conductors parallel to each other, one for the direct
and the other for the return conductor of the circuit, this organization being based
upon the theory that the inductive action of one conductor would bo counteracted
by equal and opposite action of like character in the other conductor. Although
the effects of inductive action are somewhat diminished under this arrangement,
they are by no means effectually eliminated, inasmuch as two parallel conductors
cannot be so arranged in practice, that each can be situated at precisely the same
mean distance from all neighbouring conductors, from which it results that the
inductive action in one portion of a conductor cannot accurately be compensated
by the opposite effect in another portion of the other conductor.
The Invention is based upon the discovery that if one portion of a circuit be
surrounded by the other helically, one portion passing through the mathematical
axis of the other, and being properly insulated therefrom, thus forming a solenoid,.
and either portion be used for the direct, and the other portion for the return con-
ductor of a telegraphic or telephonic circuit of any length, induced, derived, or
magnetising currents will be entirely prevented.
In the accompanying Drawings,-
Figure 1 represents the two portions of a telegraphic or telephonic circuit
organized in accordance with the principles of the present Invention.
Figure 2 shows a modification of the same, which is more suitable for practical
use.
Figure 3 is a theoretical diagram illustrating the application of the Invention
to a telegraphic circuit, and
Figure 4 in like manner represents its application to a telephonic circuit.
Two metallic conductors A, B, are shown in Figure 1 as enveloped in the ordinary
manner in insulating coatings a, b, of suitable material, the insulated conductor B
being wound helically and as closely as possible around the conductor A, as shown
at O. When the ends of the conductors are united they form a solenoid.
I make use of the double conductor, constructed as above described, of any
desired length for a telegraphic or telephonic circuit. It will be evident upon
inspection that the mean distance of the conductors A, B, from each other will be
the same throughout the entire circuit, and it will also be observed that the mean
distance of the conductors from all surrounding objects of whatsoever nature and
of whatsoever actual distance therefrom will be precisely the same. It follows
therefore that as the current in traversing the circuit necessarily flows helically in
a given direction through one conductor, and directly in the opposite direction from
the other conductor, the inductive effect of the current in each conductor while of
opposite character will be precisely equal in amount.
It is obvious that under the organization herein before described the length of the
helical conductor necessarily greatly exceeds that of the other, consequently where
of equal conductivity per unit of length the total resistance of the helical conductor
would necessarily be much greater than that of the direct one. Even under these
conditions the Invention will be operative and induction will be prevented, but it is
preferred to have the two conductors of equal resistance.
The resistance of the two conductors could obviously be modified by making
the helical one of much larger wire than the other, but such a mode of construction
is obviously objectionable for mechanical reasons.
This objection is obviated by constructing the improved conductor in the manner
shown in Figure 2, which represents the direct conductor A. as enveloped in a
compound helix consisting of several parallel conductors 1, 2, 3, 4, which number
has been found to be a convenient one in practice, which conductors are of such
thickness and electrical conductivity as to render their point resistance per unit
of conductivity measured on the direct conductor approximately the same as that
of that conductor itself.

page_text: Figure 3 represents an organization of telegraph apparatus which is preferred,
which Figure shows a battery E; a transmitting key K, a direct axial or central
conductor A connecting the key with the receiving instrument R, and four helical
conductors 1, 2, 3, 4, connected in multiple arc with the battery and receiver
respectively. This organization of apparatus constitutes what would be called by
analogy, in other forms of telegraphy, a metallic circuit, either open or closed,
according to the normal position of the transmitting key.
It is obvious that in apparatus thus organized electric currents or pulsations
transmitted through one conductor will return through the other, and that the
inductive influence of the two sets of conductors both upon each other and upon all
surrounding objects will be equal and opposite. It follows therefore that any
inductive effects of whatever nature produced in or by the direct conductor will be
neutralized by similar effects produced in the return conductor.
Figure 4 illustrates a circuit equipped with speaking telephones C, C, arranged
upon the same principles as that herein before described. The telephones act both
as receivers and transmitters, the circuit necessarily passing through them.
Any required number of independent circuits of conductors, organized as
above described, may lie parallel and close together within a single conduit or pipe,
and each conductor will be absolutely protected against the effects of induction,
both in itself and in the neighbouring conductors, whatever their number or relative
position. I am thus enabled to employ one circuit to convey a portion of the
current generated by a dynamo-electric machine and employed to transmit power
or to supply a series of electric lamps, and to use .another circuit for ordinary
commercial telegraphy, under either the Morse, the duplex, the quadruplex, or the
automatic system of transmission, while still another circuit may be employed for
oral transmission by means of speaking telephones, and any number of such circuits
may be enclosed in a single casing without in the slightest degree interfering with
each other.
The objects of the next part of the Invention are so to organize the apparatus
that any desired number of intermediate stations may be employed besides the
terminal ones, and that where a number or series of helical conductors constitute a
part of the circuit each one of them may be utilized for work independently of the
others, so that currents of different character may simultaneously be sent through
the same compound conductor, that is to say, one conductor may be employed for
the transmission of dynamo-electric currents, another for battery currents, and
another for telephonic transmission.
The Invention contemplates the employment of the most approved apparatus of
the present day; but as the details of such apparatus are well understood they need
no description here.
Figures 5 and 6 of the accompanying Drawings show these organizations arranged
in the best way now known, but the arrangement of apparatus may be varied in
well-known ways without departing from the principle of the Invention, the
distinguishing characteristic of which is the transmission of all the currents,
impulses, or pulsations in one direction through a conductor constituting the longi-
tudinal axis of a solenoid, and in the other through a series of conductors coiled
helically around said direct conductor, their circuits of course passing through the
generator and receiving and transmitting apparatus. The conductors, it will be
understood, are properly insulated from each other, and are adapted for submarine
or subterranean uses by being armored or enclosed in conduits or pipes in well-
known ways.
Figure 5 represents a theoretical diagram of the improved apparatus organized
for the transmission of both voltaic and magneto currents with a portion of the
apparatus at each station constituting a part of the direct conductor, and other
portions constituting parts of the helical conductor, the helical conductors in this
Figure being shown as united in multiple arc at their terminals, so as to constitute
in effect but one conductor.
Figure 6 represents a similar diagram showing the apparatus as organized for

page_text: the transmission of dynamo-electric, galvanic, and magneto currents, with
generating, receiving, and transmitting apparatus interposed in the helical circuits,
and with each of the helical conductors organized for. the transmission of currents
or pulsations differing in character from the others.
These Drawings each show two terminal stations and one intermediate station,
which is sufficient for the purpose of illustration, but obviously the number of
intermediate stations may be varied to any desired extent.
Under the organization shown in Figure 5, the apparatus employed at each of
the terminal stations U, W, is as follows:-
The direct conductor A is enveloped by the helical conductor B, both being
properly insulated. A battery E at each station is connected by a wire e with a
Morse key K, a wire f being connected with the helix of an ordinary relay R
provided with a local battery L and with a sounder S. A switch 8 connects the
helix of each receiver with the direct conductor A. above mentioned.
At the intermediate station V a corresponding switch a connects the direct
conductor with the helix of the receiver R provided with its local battery L and
sounder S. The wire c of this helix passes through a transmitting key K
connected by the direct conductor A with the terminal station W, as already
described.
The switch s can be turned so as to connect directly with the rheostat E and
cut out the relay R and sounder S as will be readily understood from the Drawing;
the rheostat affording means of compensating disturbances caused by cutting the
relay and sounder into or out of circuit. An ordinary microphone transmitter T
and its local battery L' are shown as included at each station in circuit with a
receiving telephone C. At the terminal stations U, W, this circuit starts from the
switch point through the wires i and through the telephones to the point j, where
it connects with the helical conductors 1, 2, 3, 4, in multiple arc. The switches
afford a means of cutting the relays, keys, and battery out of circuit, leaving the
direct conductor A short circuiting the relay in a way which will be obvious from
an inspection of the Drawings.
The telephone circuit at station V is provided with a rheostat H' to enable its
resistance to be adjusted relatively to that of the direct conductor. The switch a
in the helical conductor onables the current to be switched from the telephone
circuit to the shunt wire g, thus enabling the operator to cut out the telephone at
the intermediate station when desired. This shunt wire connects with the helical
conductors at a point beyond the intermediate station, which conductors are again
connected in multiple are at their terminal stations in a manner similar to that
above described. It will thus be seen that under the organization shown, the direct
conductor may be utilized for the transmission of galvanic or voltaic currents or
pulsations, and that the helical conductor may be used for telephonic transmission,
one or the other being thrown out of circuit by the switches as desired. It is also
obvious that this arrangement could be reversed. Of course, both sets of apparatus
cannot be used at the same time as a telephone and as a telegraph, but the
telephone receiver could be made to act as a telegraph receiver, either alone, or at
the same time that the relay and sounder are operating on the direct conductor.
The following is a description of the apparatus shown in Figure 6, that at each
terminal station X, Z, being alike.
The direct conductor A. extends from station to station without a break, while each
of the helical conductors 1, 2, 3, are connected with a different generator, transmitter,
and receiver at each station. For instance, the solid black lines show the direct
conductor A, as connected by a wire I with a key K, battery M, and sounder S at
each terminal station, and with a corresponding key and sounder at the inter-
mediate station, this conductor being marked 1. The helical conductor 2 is shown
in long dotted lines as connected through a dynamo-electric machine or generator G
at the terminal stations, and with a key. K and sounder S at each station. The
third helical conductor 3 is shown in short broken lines as connected in circuit with
ordinary magneto-telephones C at each station. The terminals of all these helical

page_text: conductors are connected in multiple arc with the direct conductor, thus forming
metallic circuits normally open or closed according to the position of the keys.
Under the above organization it is not essential that the resistance of the various
conductors should be exactly equal or balanced, but the apparatus on the contrary
will work with quite a wide range of adjustment.
I claim,―
First. In the art of transmitting intelligible signals by electricity, the method
herein set forth of preventing induction, which consists in passing the direct
current through the axial conductor of a solenoid, the return current traversing the
helix, or vice versa.
Second. An electric telegraphic or telephonic circuit composed of a solenoid,
substantially as set forth.
Third. A solenoid, the helix of which is of equal resistance with the axial con-
ductor per unit of length of the latter, as described.
Fourth. In combination with the transmitting and receiving devices of an
electric telegraphic or telephonic circuit, the line-wire or cable, in the form of a
solenoid, substantially as and for the purpose described.
Fifth. A compound electric conductor consisting of two or more parallel single
conductors formed into a helix, and united in multiple arc at their extremities, with
a single electric conductor placed in the longitudinal axis of said helix, the simple
and compound conductors forming respectively the direct and return portions of an
electric circuit. .
Sixth. The combination, substantially as hereinbefore set forth, of an electric
conductor in the form of a helix, a second electric conductor placed in the longi-
tudinal axis of the said helix, an apparatus for transmitting electrical pulsations
placed between and connected with the respective terminals of said conductors at
one station, and an apparatus for producing physical effects by means of electrical
pulsations placed between, and connected with the respective terminals of said
conductors at another station.
Seventh. The combination, substantially as herein set forth, of the direct and
helical conductors with signalling apparatus forming a portion of each conductor.
Eighth. The combination, substantially as herein set forth, of the direct and
helical conductors, signalling apparatus forming a portion of each conductor, a
short circuiting switch to throw the instrument in or out of circuit, and a rheostat
to compensate variations in the resistance of the conductors occasioned by switching
the instruments into or out of circuit.
Ninth. The combination, substantially as herein set forth, of the direct and
helical conductors, signalling apparatus forming a portion of each conductor, a
shunt, and a switch to throw a portion of the apparatus into or out of circuit.
Tenth. The combination, substantially as herein set forth, of the direct and
helical conductor, signalling apparatus forming a portion of each conductor, a
shunt, a switch, and a rheostat.
Eleventh. The combination, substantially as herein set forth, of the direct and
return conductor, signalling apparatus forming a portion of each conductor, a
rheostat in each conductor, a switch, and a shunt.
In witness whereof, I, the said Sydney Pitt, have hereunto set my hand and
seal, this First day of September, in the year of our Lord One thousand
eight hundred and eighty one.