IMPROVEMENTS IN ELECTRIC WAYS OR CONDUCTORS
Year: 1883

page_text: LETTERS PATENT to Benjamin Joseph Barnard Mills of the firm of Harris
and Mills of 23 Southampton Buildings in the County of Middlesex, Patent
Agent for an Invention of IMPROVEMENTS IN ELECTRIC WAYS OR CONDUCTORS
communicated to him from abroad by Edward M. Bentley and Walter H.
Knight both of Washington in the District of Columbia, in the United States
of America
PROVISIONAL SPECIFICATION left by the said Benjamin Joseph Barnard
Mills at the Office of the Commissioners of Patents on the 1st May 1883.
BENJAMIN JOSEPH BARNARD MILLS of the firm of Harris and Mills of
23 Southampton Buildings in the County of Middlesex, Patent Agent IMPROVE-
MENTS IN ELECTRIC WAYS OR CONDUCTORS A communication to me from abroad
by Edward M. Bentley and Walter H. Knight, both of Washington in the District
of Columbia in the United States of America
This Invention consists in the arrangement of electric conductors, running in
proximity to one another, whereby conductors carrying different classes of currents,
as electric light, telegraph and telephone wires, may be undisturbed by mutual
induction.
In the first part of the invention three general classes of conductors are used:
The conductors of one class are single or direct conductors, that is, conductors
carrying the current of a circuit in a single direction with relation to the
neighbouring conductors. They may be grounded circuits where the earth serves as
the return, or the return may be in any other way placed outside the same
inductive field with the direct. The other two classes of conductors are composed
of double circuits, the direct limb of each circuit being accompanied by its
corresponding return limb.
The first class of double circuits has each set of direct and return conductors
wound around a common axis or arranged in any other manuer so that they
will be substantially in an inductive relation to external circuits. To avoid
multiplicity of lines there is provided a single return for a number of distinct
Price 10dl

page_text: direct conductors, all being wound on a common core or all placed so that each
direct and the common return will be in the same inductive relation to external
circuits. A cable and a system of circuits for this purpose is described in the
fourth part of the invention. The second class of double circuits has each set of
direct and return conductors run in straight sections so that the single circuits may
be placed in eqnal inductive relation to each limb of the double circuit, so that
there will be no inductive effect between them. The straight double circuit is
preferably an electric light circuit and the single circuits telephone circuits. If the
two limbs of the straight double circuit are run parallel to each other in the same
plane, or a number of sets are in parallel planes, it is evident that all parallel
conductors in the median plane perpendicular to the plane of the double circuit
will be in a neutral inductive planè, being equally and oppositely affected by both
limbs of the double circuit. As the number of conductors which can be placed in
this neutral plane is practically limited, additional single circuits are brought into
the field by being so placed that they cross the neutral plane at intervals so as to
be now nearer one limb and then nearer the other limb, so that the two limbs will
exert equal and opposite inductive tendencies upon them. By this arrangement all
the single circuits and straight double circuits will be independent of each other
while the twisted or helical double circuits will be independent of all external
circuits. The three classes of conductors will thus be in mutual inductive
independence. This arrangement may be applied to aerial lines, but it is more
especially adapted to underground or other conduits where the wires can be rigidly
held in their relative positions. Any well known construction of conduit may be
used for the purpose, and the above described arrangement be carried out in
various ways.
As the single conductors must cross over the neutral plane at
intervals, such intervals are made to correspond to the distance between junction
boxes, and advantage is taken of the crossing to bring all the individual wires to a
common surface for making connection therewith.
The neutral plane being a vertical plane, there are placed in each junction box a
number of vertical sticks, and as the wires emerge from one side of one section of
the conduit into the box, they are bent around the vertical sticks and enter the
opposite side of the next section of the conduit. The sticks are so arranged that
when the wires are all crossed they form with the transverse sticks a V-shaped
vertical surface having a wicker-work like appearance, the sticks being interwoven
with and supported by the wires, and each wire being brought to the surface in a
systematic way, so as to be really accessible at each junction box, the opening of
the V-shaped connection board being on the opposite side at the successive boxes.
The second part of the invention consists in another method of accomplishing
the same purpose, which is preferable for use under certain circumstances, as for
instance when the number of light wires is small and the number of telephone or
telegraph wires is large. In this arrangement the same three classes are used,
namely one class of single circuits and two classes of double circuits, but in a
modification two classes of single circuits and one class of double circuits may be
used after the manner set forth in the third part of the invention. In this
arrangement as in the first, one class of double conductors has its circuits wound
on a common axis, but the second class has its conductors run in straight sections.
The point of difference over the first arrangement being, that instead of the single
circuits crossing from side to side of the neutral plane of the straight double circuit,
the double circuit itself has its two limbs crossed at definite intervals, so that the
positive and negative conductors interchange their lineal positions at such intervals.
Any parallel circuit will therefore be subject to equal and opposite inductive
tendencies if it passes along an even number of sections of the double circuit. All
of the single conductors can thus be straight throughout. In both the first and
second parts of the invention the two classes of conductors must be in proximity
over an even number of sections, one balf of which have an opposite inductive
tendency to the other half. A similar provision is made at the junction boxes for
crossing the conductors, which in this case will nearly always be for electric light
•

page_text: circuits. A stick of the right dimensions is placed obliquely in the junction box
and the two limbs of each circuit are given a half turn around it, the positive wire
on one side and the negative wire on the other. A yielding connection can be
used if necessary. The single circuits are also brought to a common horizontal or
vertical surface by being woven over transverse bars so as to form a connecting
board with a wicker-work-like surface as in the first part of the invention.
The third part of the invention consists in an arrangement for use in smaller
ways or in sub-mains.
In this arrangement three, four or more classes of conductors can be used and
those of only one class need be doubled. Two or more single conductors are placed,
each of them equi-distant from the direct rotum limbs of the double circuits, and
are protected from one another by a metallic shield. In practice the metal of the
double circuits performs the additional function of a metallic shield. These are
preferably the light circuits, and are made in strips, which in one form are bent
at right angles so as to be more conveniently interposed between the individual
conductors.
The fourth part of the invention consists of a cable which may be conveniently
used in the first two arrangements described above for the double circuit which is
wound so as to be in anti-inductive relation to all external circuits, and also in the
application of this cable to a system of electric conductors. Upon a common core
which may be of insulating material or of one or more insulated single conductors
are wound in parallel helices one or more distinct direct conductors and a common
return conductor therefor. The batteries in the several direct circuits preferably
having half of them their positive and half of them their negative plates connected
to the common return. The conductors are preferably of the same size and any
number may be used for direct and any number for return circuits. In the system
the return conductor for through lines is put to ground as soon as it reaches the
limit of thé disturbed area. For local lines there is no earth connection whatever,
but all branch and loop conductors are connected to the common return.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Benjamin Joseph Barnard Mills in the Great Seal Patent Office
on the 31st October 1883.
"
BENJAMIN JOSEPH BARNARD MILLS of the firm of Harris and Mills of
23 Southampton Buildings in the county of Middlesex Patent Agent " IMPROVE
MENTS IN ELECTRIC WAYS OR CONDUCTORS A communication to me from abroad
by Edward M. Bentley and Walter H. Knight both of Washington in the District
of Columbia in the United States of America
This invention consists in the arrangement of electric conductors running in
proximity to one another whereby conductors carrying different classes of currents,
as electric light, telegraph and telephone wires may be undisturbed by mutual
induction.
In the first part of the invention three general classes of conductors are used.
The conductors of one class are single or direct conductors that is conductors
carrying the current of a circuit in a single direction with relation to the neigh-
bouring conductors. They may be grounded circuits where the earth serves as
the return or the return may be in any other way placed outside the same inductive
field with the direct The other two classes of conductors are composed of double
circuits the direct limb of each circuit being accompanied by its corresponding
return limb.
The first class of double circuits has each set of direct and return conductors
wound around a common axis or arranged in any other manner so that they will
be substantially in an inductive relation to external circuits. To avoid multiplicity
of lines there is provided a single return for a number of distinct direct conductors
all being wound on a common core or all placed so that each direct and the common
return will be in the same inductive relation to external circuits. A cable and a
system of circuits for this purpose is described in the fourth part of the invention.
The second class of double circuits has each set of direct and return conductors
run in straight sections so that the single circuits may be placed in equal inductive
relation to each limb of the double circuit so that there will be no inductive effect
between them. The straight double circuit is preferably an electric light circuit
and the single circuits telephone circuits. If the two limbs of the straight double
circuit are run parallel to each other in the same plane or a number of sets are in
parallel planes it is evident that all parallel conductors in the median plane
perpendicular to the plane of the double circuit will be in a neutral inductive
plane, being equally and oppositely affected by both limbs of the double circuit.
As the number of conductors which can be placed in this neutral plane is practically
limited additional single circuits are brought into the field by being so placed that
they cross the neutral plane at intervals so as to be now nearer one limb and then
nearer the other limb so that the two limbs will exert equal and opposite inductive
tendencies upon them. By this arrangement all the single circuits and straight
double circuits will be independent of each other while the twisted or helical double
circuits will be independent of all external circuits. The three classes of conductors
will thus be in mutual inductive independence. This arrangement may be applied
to aerial lines but it is more especially adapted to underground or other conduits
where the wires can be rigidly held in their relative positions. Any well known
construction of conduit may be used for the purpose and the above described
arrangement be carried out in various ways. As the single conductors must cross
over the neutral plane at intervals such intervals are made to correspond to the

page_text: distance between junction boxes and advantage is taken of the crossing to bring all
the individual wires to a common surface for making connection therewith.
The neutral plane being a vertical plane there are placed in each junction box a
number of vertical sticks and as the wires emerge from one side of one section of
the conduit into the box they are bent around the vertical sticks and enter the
opposite side of the next section of the conduit. The sticks are so arranged that
when the wires are all crossed they form with the transverse sticks a V shaped
vertical surface having a wicker-work like appearance the sticks being interwoven
with and supported by the wires and each wire being brought to the surface in a
systematic way so as to be readily accessible at each junction box the opening of
the V shaped connection board being on the opposite side of the successive boxes.
The second part of the invention consists in another method of accomplishing
the same purpose which is preferable for use under certain circumstances as for
instance when the number of light wires is small and the number of telephone or
telegraph wires is large. In this arrangement the same three classes are used
namely one class of single circuits and two classes of double circuits but in a
modification two classes of single circuits and one class of double circuits may be
used after the manner set forth in the third part of the invention. In this
arrangement as in the first one class of double conductors has its circuits wound on
a common axis but the second class has its conductors run in straight sections.
The point of difference over the first arrangement being that instead of the single
circuits crossing from side to side of the neutral plane of the straight double
circuit the double circuit itself has its two limbs crossed at definite intervals so
that the positive and negative conductors interchange their lineal positions at such
intervals. Any parallel circuit will therefore be subject to equal and opposite
inductive tendencies if it passes along an even number of sections of the double
circuit. All of the single conductors can thus be straight throughout. In both
the first and second parts of the invention the two classes of conductors must be
in proximity over an even number of sections one half of which have an opposite
inductive tendency to the other half. A similar provision is made at the junction
boxes for crossing the conductors which in this case will nearly always be for
electric light circuits. A stick of the right dimensions is placed obliquely in the
junction box and the two limbs of each circuit are given a half turn around it,
the positive wire on one side and the negative wire on the other. A yielding
connection can be used if necessary. The single circuits are also brought to a
common horizontal or vertical surface by being woven over transverse bars so as
to form a connecting board with a wicker work-like surface as in the first part of
the invention.
The third part of the invention consists in an arrangement for use in smaller
ways or in sub-mains. In this arrangement three four or more classes of conductors
can be used and those of only one class need be doubled. Two or more single
conductors are placed each of them equidistant from the direct and return limbs
of the double circuits and are protected from one another by a metallic shield.
In practice the metal of the double circuits performs the additional function of a
metallic shield. These are preferably the light circuits and are made in strips
which in one form are bent at right angles so as to be more conveniently
interposed between the individual conductors.
The fourth part of the invention consists of a cable which may be conveniently
used in the first two arrangements described above for the double circuit which is
wound so as to be in anti-inductive relation to all external circuits and also in the
application of this cable to a system of electric conductors. Upon a common core
which may be of insulating material or of one or more insulated single conductors
are wound in parallel helices one or more distinct direct conductors and a common
return conductor therefor. The batteries in the several direct circuits preferably
having half of them their positive and half of them their negative plates connected
to the common return. The conductors are preferably of the same size and any
number may be used for direct and any number for return circuits. In the system

page_text: the return conductor for through lines is put to ground as soon as it reaches the
limit of the disturbed area. For local lines there is no earth connection whatever
but all branch and loop conductors are connected to the common return.
And in order that the said Invention may be more clearly understood and
readily carried into effect I will proceed aided by the accompanying drawings
more fully to describe the same.
accompanying drawings.
Figures 1. 2. 3 and 6 represent electric circuits arranged according to the
invention.
Figure 4 is a perspective view with parts broken away of a conduit containing
the arrangement of circuits.
Figure 5 shows the invention applied to aerial lines the wires crossing one
another at the posts.
Figure 7 shows a junction box in the conduit.
Figure 8 is a diagram showing circuits entering and leaving the system and
Figure 9 is a detail of the junction box.
The wires in this system are divided into three classes, viz, telephone wires,
light wires and telegraph wires, the last including telegraph wires of all kinds as
fire, district and stock telegraphs as well as ordinary telegraph wires.
Assuming that wires of any class can be placed within moderate distance of
each other without danger means are provided whereby the wires of one class shall
not be disturbed by the induction from the wires of any other class. It is
necessary for safety and convenience that all light circuits should be provided with
a metallic return. Advantage is taken of this fact to provide a basis for rendering
a second class of wires preferably the telephone wires safe from disturbance from
the light wires.
Let A and. A Figure 1 be the direct and return wires of an electric light circuit
then every parallel wire which is in the median plane perpendicular to the plane
A A. is in a field of no induction the two limbs A and A tending to produce equal
and opposite effects but as the number of wires which can be in this plane is very
limited I provide an arrangement whereby wires out of this plane are in a neutral
position. A cross section of two dimensions can thus be filled with wires in non-
inductive positions and the number that can be so placed is practically unlimited.
To accomplish this I run every telephone wire T which is out of the median or
neutral plane an equal distance in close proximity to each limb A A alternately
the wire crossing from one side to the other at intervals. Figure 2 shows how
any number of telephone wires T and any number of light wires A A may be
arranged in this manner all the telephone wires crossing each other at the same
point and each being in the same relation to every set of light wires A A in the
vertical column. In practice the wires T will be braided over one another as
shown in Figures 6 and 7 at each junction box so that every wire may be brought
to the surface for the purpose of testing and making connections. If now a single
telegraph wire be brought into the inductive field of a series of light and telephone
wires arranged in the manner above described it will be disturbed by the light
wires and will itself disturb the telephone wires. To render it entirely neutral
with respect to the others it must be doubled when it will not induce into other
wires or be induced into; but as it would be a great expense to double all
telegraph wires we provide a single return for a number of direct wires.
On trunk lines this common return wire will be put to ground outside the city
or area of disturbance, the batteries on each half of the direct lines may have
their opposite poles connected to the common return and the return may be of
better conducting material than the direct. Therefore one return can be used for
a great number of direct circuits and it will perform all the function of a ground

page_text: return and will in addition neutralize the inductive effect of the direct wires.
P Figure 3, is the the telegraph wires arranged in proximity to the light
wires A, A, and the telephone wires T. d, d, are the direct wires and r is the
common return therefor, they being wound together in parallel spirals around an
insulating core C, so that they both hold continually the same relation to external
wires. In Figure 4 is shown an application of the above described combination of
wires to a conduit. C shows a part of a conduit built up of masonry or in any
suitable manner. Within C are shown the wires in grooved or perforated blocks
of suitable material; though they may be supported and insulated in any manner
desired. On either side of the conduit are shown the direct and return light
wires A, A1, in vertical rows. In the centre of the conduit are first the anti-
induction telegraph cables P in blocks S and above them the telephone wires laid
in grooves in blocks B and crossing one another at an intermediate point of the
conduit. If necessary a thin layer of metal may be placed between the several
blocks B to prevent inter-induction between wires T. Figure 7 shows a junction
box with part of the wires broken away at which all wires are accessible for
testing and connections. The light wires A, A, are seen running across on each,
side of the box, the upper part of those in front of the box being broken away.
a, a is a loop taken from the upper inside wire in the back of the box and led out
through opening O to supply an arc lamp. An incandescent lamp is supplied by
wires I, I, taken from main lines K, K, and let out through the same opening. The
telegraph wires P, which are intended for through lines, are led directly across,
while one or more of those intended for local use are looped up over a cross-bar E,
extending between the walls of the box. The top of this bar is provided with saw
cuts, into which the individual wires of the cable F are placed so that they may
each one he accessible. p and h are respectively a direct line and a loop taken
out through opening C in the side of the box. The telephone wires T are led into
the box and are there braided or woven across each other in the manner shown in
Figure 6, so that a V-shaped depression is left on alternate sides of the bank of
wires at each junction box. By this arrangement every wire is brought to the
surface so as to be accessible and at the same time the proper inductive relation to
neighboring light wires is preserved. This is neatly accomplished by bending the
wires around notched sticks D Figure 9 which are rectangular or diamond-shaped,
in cross section, and then around similar sticks D' triangular in cross section.
Thus all the wires in the vertical row on the front side of the box are led
around D¹, then around D, and then enter the vertical row of holes on the back
side of the box into the next section. The succeeding vertical rows are treated in
like manner. The pieces D, D', are held in place by the strain of the wires, and
when the wires are all in place, form a converging or V-shaped switch board
where all the wires are properly numbered and classified. The box is shown as
provided with a cover and suitable drainage, though these details do not pertain
to the Invention. The wires T may be used as telegraph wires and the wires P
as telephone wires.
In Figure 8 is shown a diagram of the system as applied to a number of
telephone and light wires as they are arranged in the streets of a city.
U U represent crossing streets, A. A¹ the light mains, and T the telephone wires.
V is a telephone central station and v, v, v, subscribers' stations. u represents a
dynamo feeding the are light u¹ and u" is a series of incandescent lamps supplied
as shown by multiple arc from the street mains. It will be seen that each circuit
leaves the conduit at a distance of an even number of sections from the place
where it entered, so that there will be as much positive as negative induction and
thus produce the desired neutrality.
As shown in the drawing, in case of the line w, it may be necessary in order to
bring the wire out at a certain junction box to lead the wire into the conduit on
the farther side of the street up which it comes. By this means a wire led into
the conduit from a side street may be taken out at an even or odd number from
the corner by taking care that it passes into the conduit from that side of the

page_text: street which is an even number of sections away from the house to which the wire
is to lead.
In order to effect this, two or more junction boxes should be provided wherever
the way crosses a street and these junction boxes as well as all the others, should
be separated by a distance of one or more whole sections.
It is evident that in the arrangement shown in Figure 1, the two light wires
may cross each other at intervals and the telephone wires remain straight as
indicated in Figure 10. The conduit is shown as provided with vacant openings
for the reception of new wires.
The second part of the Invention is illustrated in Figures 11 to 17 inclusive.
Figure 11 is a diagram of two circuits in mutual anti-inductive relation.
Figure 12 represents a method of laying the different classes of conductors in
different parts of the street.
Figure 13 shows a convenient means for introducing additional conductors.
Figure 14 is a perspective view, showing the arrangement at the junction box.
Figure 15 shows a yielding connection between two sections of conductors.
Figure 16 illustrates by a partial perspective the mode of crossing the
conductors.
Figure 17 is a side elevation showing the manner of bringing the telephone or
telegraph wires to the surface at the junction box.
There are represented herein, conductors of three different classes, viz: electric
light, telephone and telegraph conductors, the latter including fire, district printing
and all other telegraphs, and the light wires being also used for the transmission
of power and for other desirable purposes. In Figure 11, A, A¹, represent the
district and return wires of a complete metallic circuit, preferably a light circuit,
and T, T, represent neighboring conductors. A, A', are situated in the same plane
and cross each other at intervals so that the positive and negative wires exchange
positions, the positive wire taking up a position in a line which is a continuation
of the previous section of negative wire and vice versa.
It will thus be seen that any neighboring wires as T, T, in any position parallel
to A, A¹, will be subject to equal and opposite induction provided they pass along
an even number of sections of A, A¹. T, T, may be either telephone or telegraph
wires, preferably telephone wires, and if a third class of wires be brought into the
vicinity it will only be necessary to render them independent of T, T. This may
be done by providing a common return for them as in the first and fourth parts
of the Invention, or by inserting a metallic shield between them as is set forth
in the third part of the Invention. These various classes of wires may be all in
the same conduit as in the parts of the Invention referred to, and as shown in
Figure 14, or the different classes be put in different parts of the street.
In Figure 12, the light wires and through telegraph wires are shown in a
conduit in the middle of the street, while the telephone and local telegraph wires
are at the side, just inside the curb. A light wire is shown taken out to the side
of the street from the central conduit. In any case the wires should be crossed at
intervals, preferably at the junction boxes, which are situated at convenient
distances apart along the line. Figure 14 shows such a junction box with the
light wires crossed and the telephone wires brought individually to a common
surface at the top of the box, by means of a connection board made up of transverse
sticks of wood woven in among the wires in a similar manner to that in the first
part of the Invention.
.
The light wires occupy the centre of the conduit in a vertical line from top to
bottom, the sets of positive and negative wires A and A, each emerging from
the section of conduit D, into the junction box in two vertical rows on either side.
Between the two central rows, one of which of course is positive and the other
negative wires, a square stick B, of wood or other suitable material is placed
obliquely in the vertical plane of the conduit from the upper to the opposite lower
corner of the junction box and each pair of wires A, A, is brought out into the box
until they come to the stick B, one on each side of the stick. Each wire then

page_text: takes a half turn around the stick, see Figure 16, one A going obliquely across the
under surface of B to the edge, and then up at an angle to the edge, to the
diagonally opposite edge from which it started, and thence on in the line of
direction of A; the other wire A is first bent up at an angle to B and thence
obliquely across the upper surface to the diagonally opposite edge from which it
started and then goes on into the next section in the line of direction of wire A.
At a point lower down on B the next pair of wires A, A', cross each other by being
bent respectively over and under B in like manner.
It will be seen that the pairs of wires will be laid over B in an orderly manner
so that they will be readily accessible and a certain distance maintained between
each pair of wires.
For the next two rows of wires, four small sticks G are placed parallel to B, one
at a short radial distance from each corner, so that the four form a square frame
enclosing B and concentric and symmetrical with it. The outer rows of wires
A, A', are then bent by pairs around this skeleton stick just as the inner rows
were bent around the inner solid stick B. When rods are used for conductors as
in the present incandescent systems, it will be necessary to provide yielding
connections to allow for the expansion and contraction of the rods under varying
temperature. In Figure 15, A and A' are conductors of a circuit, insulated and
supported in any convenient way. At points of junction, these conductors cross
each other and are connected by means of the curved spring strips E, E¹. These
strips serve a triple function, being electrical connections, holding the two
conductors at the proper distance apart while crossing, and also allowing for
expansion and contraction of A, A'. Existing systems where connections of this
kind are used, can be rendered anti-inductive to all external conductors by simply
crossing the connections at each juncting box, so that the positive and negative
conductors occupy a reversed position in successive sections.
The manner of bringing all the wires of a system normally occupying a cross
section of two dimensions to a common surface is illustrated in Figures 14 and 17.
A number of triangular sticks F are laid just above the wires in a horizontal
plane, parallel and close to each other and transverse to the line wires. The
successive wires T in each vertical row are brought up and bent respectively over
the successive sticks F they are then brought down again to the proper level for
continuing their course into the next section in a straight line, their relative
horizontal position being maintained by bending them again around sticks F.
This arrangement forms a connection board made up of transverse sticks, and
wires woven together and present wicker work like surface. The sticks are
held in place by the wires and all the lines are brought to the surface in a
systematic way.
In Figure 14 the telegraph wires, are on the opposite side of the light wires
from the telephone wires. They may be run in anti-inductive cables, or the mass
of metal of the light wires may be relied upon as an inductive shield to protect the
two from each other.
The lower portion of the space. Figure 14, for telegraph wires is shown occupied
by cables containing through lines. The upper part is filled or partly filled with
local wires laid in insulating strips. These may be brought up to the surface like
the telephone wires, and others added as the needs of the service require.
Figure 13 shows the most convenient way of introducing new conductors or
insulating strips filled with conductors or grooved for their subsequent reception. The
whole or part of a section G between two junction boxes is left open or accessible,
while the rest of the sections are permanently covered up. To put in new con-
ductors or new holders the section G. is opened and then conducting rods, grooved
boards or other rigid objects can be laid down in G and passed through succeeding
sections, from one junction box to another, until the entire conduit space is filled.
Figures 24 to 29, inclusive illustrate the third part of the invention.

page_text: Figures 26 and 27 are sections of the conductors arranged according to my
invention
Figure 25 shows this general arrangement in perspective.
Figures 24 and 29 show the application of the invention to conductors, in
conduits and.
Figure 26 shows a diagram of a part of the circuits of Figure 24.
It is well known that if the two parallel limbs of a complete metallic circuit be
everywhere equally distant from a second single or grounded parallel circuit they
will induce no current therein, the inductive tendency of the direct current in one
limb being neutralized by that of the return current in the other limb. Under the
same circumstances also the single circuit will not induce into the double circuit,
as it tends to set up a current in the same direction in both its limbs, and such
two induced currents being equal and opposite neutralize each other. It is also
known that if a mass of conducting material be interposed between two parallel
circuits, the inductive energy of the current in each will mainly expend itself upon
the intervening metal and not affect the neighboring circuit. By combining these
principles I am enable to run several single circuits with one double circuit in
proximity to one another without inductive disturbance.
In Figure 27 A. A¹. represent sections of the two parallel limbs of a metallic
circuit formed of conducting strips and D. D'. a section of similar connecting wires
and placed between them are the single circuit wires a and b which are separated
by a metallic strip Z. By this arrangement a. and b are in the neutral plane of
A. A¹. or D. D'. and are protected from each other by screen Z. It is preferable
however to make the metal of the double circuit serve also as the inductive screen
between the other circuits. As a light circuit is necessarily a double circuit and
contains the most metal it is best adapted for the one double circuit of the system.
It is preferable that the conductors of the light circuit should be made of thin
strips of metal, as they thus afford a greater protecting surface.
In the form shown in Figures 26, 28 and 29 these two conductors A and A¹ are
bent at an angle and then placed adjacent to each other with the sides of the
angles parallel and the sides x and y overlapping each other as shown. Midway
between sides x and y is placed the conductor 6 and above and below them are the
conductors a and c. By reference to diagram, Figure 26 it will be seen that b is
exactly symmetrical with relation to A. A. and is equidistant from them and that
a and c. can be moved from or toward A or A¹ until they also reach positions
equally distant from the light conductors. a b and c. are therefore neutral with
respect to A and A¹ and are protected from one another by the intervening metal
sheets X and Y. It has been found couvenient to use wire 6 for telephonic, and a
and c. for telegraphic purposes, but the character of the current. in the several
circuits is not deemed essential and one may be used for a fourth class of circuits.
In adapting this arrangement of conductors to underground lines a conduit C,
Figure 29 of any convenient material and construction is used which may be
placed under the pavement of the street or in a hollow curbstone or under the
sidewalk. Within this conduit are piled up a number of blocks B of the proper
size and shape which have been perforated longitudinally for the passage of wires
or cables a. b. c. If cables are used the wires therein should be wound or twisted
symmetrically with relation to the centre. The strips A. A'. are slipped in between
the blocks and bent up at the sides. Care should be taken that the conductors
a. b. c. are rigidly beld in the proper relation to A. A. Figure 24 shows a section
of a conduit in which another form of the invention is arranged. On the two sides
of the conduit C' in vertical compartments are placed the telegraph wires or
cables P insulated and supported in any suitable way. In the centre of the conduit
vertically arranged, are the telephone wires T, and on either side of them are the
direct and return wires of the light circuits, made in strips or bars, and forming
altogether a metallic wall between the telephone and telegraph wires. The tele-
phone wires which are out of the neutral plane of the light wires cross each other

page_text: at intervals, as shown in Figure 25 so as to run an equal distance in the neigh-
borhood of each limb of the light circuits, as in the first part of the invention.
The light conductors A. A'. form a protective shield between the telegraph and
telephone wires, the telephone wires are protected from the light wires by the
crossing described: while the telegraph wires are placed at such a distance from the
light wires as to be but little disturbed thereby, the proximity of the return con-
ductor also allowing but a differential effect.
The fourth part of the invention is fully illustrated in Figures 18 to 23 of the
Drawings, wherein
Figures 18. 19, 20 and 21 represent cables embodying the invention.
Figure 22 represents a core made up of several parallel wires.
Figure 23 represents a diagram of the manner of their use in a system.
C represents the core of the cable which may be simply a rope or rod of
insulating material, as in Figures 20 and 21 or may be composed of an insulating
wire as shown in Figure 18, or several wires, as shown in Figures 19 and 22.
Around C, Figure 18, are wound in substantially parallel helices the direct and
return wires D and R of an electric circuit, they being insulated in any manner,
either before being wound on the core or by being embedded in the material of
the core itself. It will be seen that D and R, being thus wound have always the
same relative position to any external wire as A and neither affect it inductively
nor are affected by it. It will also be seen that they are similarly situated with.
respect to an internal wire T so that the core can be made up of such wires and
they will all be inductively independent of the wires D and R. In Figure 18 D
and R represent a telegraph circuit and T a telephone wire, but this arrangement
may be reversed as shown in Figure 19, or any other electrical translating devices
used on the various circuits..
Where C is made up of insulated wires they may be a simple bundle of straight
parallel wires as shown in Figure 22, or a number of wires T may be wound on a
core c, and the whole then serve as a core upon which wires D and R may be
wound. This arrangement is illustrated in Figure 19.
As thus far described the invention does not provide for but one direct and
return circuit in a cable-Any number of direct and any number of return circuits
may, however, be used, In Figure 20 are shown four direct circuits each provided
with a battery, transmitter and receiver and one common return circuit therefore,
two direct being on each side of the common return; in Figure 21 there are six
direct and two return circuits. Any number of wires may be used as direct
circuits, and any number as return circuits. For telegraphic purposes where the
quantity of electricity to be carried is small, and on long lines, where the common
return is only run a short distance, as to the edge of the city or outside the aren
of inductive disturbance, one common return can be used for a number of direct
circuits. It can be used with a still greater number if the batteries on one half of
the direct circuit have their positive and the other half their negative plates
connected to the common return, as shown in Figure 20.
In the diagram, Figure 23, D and R represent respectively the direct and
common return circuits for trunk lines starting from the central office O, and
running along the main street of a city and off to a distant station. D' and R'
represent the direct and common return circuits used for local business and
starting from the same central office.
It is to be understood that they are all running in the vicinity of other
disturbing wires, as in the first part of the invention. The common return R of
the through lines is grounded outside the city limits or the area of inductive
disturbance of light and telephone wires. Its resistance compared with the total
length of the through line wires is therefore very small, although it may be small
in cross section and the effect will be the same as if all the through lines were
grounded at the central office. The local lines are not grounded at all, but all
return through the common wire R¹. L is a loop of a local line passing through
the stations a. b. c. and d, and as at each point of the loop there is a direct wire

page_text: accompanied by its corresponding return wire, it is anti-inductive to any line in
its vicinity. L is a second loop going through stations e. f and g. This loop is
anti-inductive only from h to r. a single circuit going completely around the
block J. M and N are sub-stations connected with the central office by several
wires which are in each case accompanied by the common return.
The advantage of this system is that by the addition of a small number of wires
for returns, existing systems can be rendered inductively independent of other
wires wherever it is necessary, no change in or addition to the present instruments
being required. As no telegraph wires are grounded in the city there will be no
danger of telephone wires being disturbed by branch currents from ground plates,
which is considered one of the most prolific sources of telephone disturbances.
The proportions, specific relations and mechanical details of the devices may
evidently be changed, as well as the general manner indicated of carrying out the
invention, without departing from the spirit of the invention, so long as the general
principles herein before laid down are adhered to.
Having thus described the nature of the said invention and the manner of
performing the same I would have it understood that what I claim is :—
1 The general arrangements of circuits carrying different classes of currents and
placed in mutual anti-inductive relation to each other according to the general
principles herein before set forth.
2nd The electric way containing different classes of conductors, substantially as
herein before set forth.
3rd The combination of the direct and return wires of an electric circuit
having a single neutral inductive plane, with a part of a second circuit,
arranged alternately on opposite sides of said neutral plane, so as to avoid inductive
effects.
4th In an underground conduit provided with junction bosses, dividing the
conduit into sections, two classes of conductors, one disturbing and the other
protected from disturbance therefrom, the conductors of the two classes extending
for one section, or a certain number of sections or fractions of a section in such
proximity as to produce a certain inductive tendency, and then changing their
relative positions and extending a certain distance in such proximity as to produce
an equal and opposite inductive tendency.
5th In combination with the direct and return wires of a disturbing circuit, a
second single wire arranged in nearer parallel proximity to the direct wire at one
point and in like parallel proximity to the return wire at another point.
6th The combination in an anti-inductive system of electric wires of a grounded
or single circuit and two separate direct and return circuits, one of which is formed
of two wires running in straight sections.
7th The combination of a conduit for electric wires made in longitudinal
sections, a direct and return circuit therein, and single wires inductively
symmetrical to said circuit and crossing one another at intermediate points of the
section.
8th The combination of two wires forming the direct and return of one circuit
and having a neutral inductive plane, or a series of such neutral planes, with a
third wire forming part of another circuit, one of the circuits crossing the
neutral plane at intervals so that the induction in the section between any
two adjacent crossings will be neutralised by the opposite induction of the next
section.
9th The combination of two wires forming the direct and return of one circuit,
with a third wire forming part of another circuit, one of the circuits changing its
relative position to the other at definite intervals but remaining in substantially
constant relation between such points of change so that the induction in the section
between any two adjacent points of change will be neutralized by the opposite
induction of the next section.
10th An anti-inductive system of wires carrying different classes of currents in
which all the wires run in straight or substantially straight sections in the

page_text: direction of the line of way, and in which the wires of one class reverse their
inductive positions at intervals with respect to the wires of the other class..
11th The combination with the direct and return wires of one circuit of a second
circuit arranged parallel in sections with, and alternately in proximity to, the said
direct and return wires.
12th Two wires forming the direct and return of one circuit with a single
neutral plane and a third wire forming part of another circuit arranged symme-
trically to but out of the said neutral plane.
13th Two wires forming the direct and return of one circuit with a third
wire forming part of another circuit and running first parallel and near to one
limb and then in like inductive relation to the other limb of the metallic
circuit.
14th In an underground electric wire conduit, two classes of conductors laid in
anti-inductive relation in strips, the said strips being held rigidly at definite
distances apart.
15th The combination of the conductors T and the insulating rods D, the
conductors being woven around the rods like wicker work so that each and every
wire comes to the surface.
16th An electrical connecting board formed of conductors and transverse
insulating bars woven together, substantially as shown and for the purpose set
forth.
17th An underground electric conduit, having the light wires extending along
one side of the conduit, and returning on the other side, telephone wires between
and parallel to the light wires and crossed at intervals so as to avoid induction,
and telegraph wires arranged anti-inductively with the other wires.
18th An underground electric way having light circuits, running in straight
sections and telephone wires in alternating inductive proximity to the two limbs
of the light circuit.
19th An underground electric way having light circuits running in straight
sections, telephone wires in alternating inductive proximity to the two limbs of the
light circuit and telegraph circuits in anti-inductive relation to both the light wires
and the telephone wires.
20th An underground electric way, divided into sections and having light wires
running in substantially straight lines through each section, and telephone or
telegraph wires also running in substantially straight lines through each section,
one of the different classes of wires being crossed over at the ends of the section
so that the different classes of wires run in positive inductive proximity along one
section and in equal negative inductive proximity along another section.
21st A direct and return wire forming a complete metallic circuit in combination
with a number of single circuits laid in layers and occupying planes parallel or
nearly parallel with the plane of the metallic circuit, the wires of each layer
crossing over from side to side of the layer, at intervals, so as to neutralize induction
from or to the metallic circuit.
22nd An electric way comprising two or more classes of conductors divided into
longitudinal sections, the even sections being equal and opposite the odd sections in
inductive influence.
23rd An electric way, comprising two or more classes of conductors and divided
into longitudinal sections, the said sections being of equal but alternatively opposite
mutual inductive influence, and having circuits entering and leaving the way at a
distance apart of an even number of such sections.
24th An underground electric way, divided into equal but alternatively opposite
inductive sections and having at the street crossings two or more junction boxes,
eparated by the length of one or more sections so that wires from a side street
may be led into either an even or an odd section for the purpose set forth.
25th The combination of a direct and return circuit having a neutral plane or a
series of neutral planes, of two or more single circuits ranning parallel with and at

page_text: different distances from the said plane or planes and crossing the plane or planes at
intervals, substantially as and for the purpose set forth.
26th An anti-inductive system of electric wires in which the wires cross and
recross at intervals, each crossing being the reverse of the adjacent crossings 80 as
to have neutral inductive action with regard to other parallel circuits.
27th The combination with an external conductor of the direct and return
conductors of an electric circuit, said direct and return conductors exchanging their
lineal positions at intervals.
28th The combination with an external conductor of a pair of inductively
opposing sections of the direct and return conductors of an electric circuit, the
direct and return conductors in said sections being in the same plane.
29th The combination of the direct and return conductors of an electric circuit,
said conductors crossing each other at sectional. points, and each section having a
corresponding inductively opposing section in the same plane.
30th The combination of the direct and return conductors of an electric light
circuit, said conductors crossing each other at sectional points, each section being in
one plane and having a correspondingly inductively opposing section in the same
plane.
31 In an electric way divided into longitudinal section the combination of the
direct and return conductors of a metallic circuit and a portion of another circuit,
the wires all running substantially parallel throughout each section and the direct
and return conductors crossing each other at the ends of the sections so as to inter-
change their lineal positions, substantially as and for the purposes set forth.
32nd In an electric way divided into longitudinal sections, the combination of
the direct and return conductors of a metallic circuit crossing each other at the
ends of the sections with a portion of another circuit extending the distance of an
even number of sections along the way for the purpose set forth.
33rd The combination with a number of permanently closed sections of an electric
way of an open or accessible section for the introduction of rigid conductors or wire
holders.
34th The combination of two electric conductors, crossing each other but not
coming in contact nor in comparatively close proximity of a separating stick, each
of the two conductors making a half turn around the stick.
35th The combination with a series of pairs of electric conductors of the oblique
stick B, the pairs of conductors crossing each other at successive points of the
stick.
36th The combination with stick B and conductors arranged thereon of an
external frame and conductors similarly arranged upon it.
37th The combination with wires in layers of transverse bars in a single surface,
the successive layers of wires being looped over the successive bars so as to be
brought to the single surface.
38th The combination of wires T and bars F and F, substantially as described.
39th The combination of electric wires in a conduit in the centre of the street
with wires of different classes arranged at the sides of the street, in anti-inductive
relation to the central wires.
40th The combination with two electric conductors crossing each other of
expansible cross connections.
41 The combination of conductors A A', and curved or bent expansible crossed
connectors E E¹.
42 The combination of three classes of electric conductors within inductive
proximity of one another, two of the three classes having each, one or more single
or grounded circuits, and the third class having one or more double or return
circuits, the whole being arranged in mutual inductive independence.
43rd The combination of four classes of electric conductors, within inductive
proximity of one another, three of the four classes having each, one or more single

page_text: or grounded circuits, and the fourth class having one or more double or return
circuits, the whole being arranged in mutual inductive independence.
44th The combination in the same circuit of one or more single telephone circuits,
one or more single telegraph circuits, and one or more double light circuits,
arranged in mutual inductive independence.
45th The combination of two single circuits, each equally distant from the two
limbs of a parallel double circuit, and protected from each other by a metallic
shield.
46th The combination of two electric circuits, and an inductive shield forming
part of a third circuit.
47th The combination of two electric circuits and an inductive shield forming
part of an electric light circuit.
48th The combination of one or more single telegraph circuits, one or more single
telephone circuits and a parallel double circuit, the telegraph and telephone circuits
being each equally distant from the two limbs of the double circuit and protected
from each other by a metallic shield.
49th The combination of one ог more telegraph circuits, and one or more
telephone circuits, protected from each other by a metallic shield forming part of
a third circuit.
50th The combination of one or more telegraph circuits, one or more telephone
circuits, and an electric light circuit, the light circuit conductor serving as an
inductive shield between the telephone and telegraph circuits.
51 The combination of one or more single telegraph circuits, one or more single
telephone circuits, and one or more double light circuits, the conductor of the light
circuit or circuits serving as a protective shield between the telephone and telegraph
circuits.
52nd The combination of one or more electric circuits of the same class, one or
more electric circuits of a second class, and a double circuit of a third class, the
circuits of the first and second classes being each equally distant from the two limbs
of the double circuit, serving as an inductive shield between circuits of the first two
classes.
53rd An electric light conductor formed in a rectangular bar or strip and serving
as an inductive shield.
54th The combination with electric conductors and supporting blocks, of an
inductive screen, inserted between the block.
55th The combination of several direct conductors and one or more common
return conductors therefor, each direct conductor and the common return con-
ductor or conductors being practically equi-distant from any neighbouring parallel
conductor.
56th The combination of several direct conductors forming distinct circuits and
a common return therefor, the whole arranged in anti-inductive relation to
neighbouring parallel circuits.
57th The combination of several direct conductors and one or more return
conductors therefor, the whole arranged in anti-inductive relation to neighbouring
parallel circuits, the return conductors being arranged symmetrically between the
direct conductors.
58th The combination of several direct conductors, and a common return therefor,
with neighbouring disturbing wires, the return conductor being grounded outside
the area of inductive disturbance.
59th The combination of several direct conductors and a common return therefor
with loop circuits taken from the direct conductors.
60th The combination of several direct conductors and a common return therefor
of a branch from the common return serving as a return for one or more of the
direct conductors.

page_text: .61 The combination of the direct and return limbs of an electric circuit
wound on a conducting core made up of one or more single limbs of an electric
circuit.
"
In witness whereof I the said Benjamin Joseph Barnard Mills have hereunto
set my hand and seal this twenty ninth day of October in the year of our Lord
One thousand eight hundred and eighty three.
B. J. B. MILLS (LS.)