IMPROVEMENTS IN ELECTRICAL CONDUCTORS, AND IN THE ARRANGEMENT AND MANNER OF USING CON- DUCTORS FOR TELEPHONIC AND TELEGRAPHIC PURPOSES." PROAL
Year: 1880

page_text: LETTERS PATENT to Oliver Heaviside, of No. 3, Saint Augustine's Road, in the
County of Middlesex, for an Invention of "IMPROVEMENTS IN ELECTRICAL
CONDUCTORS, AND IN THE ARRANGEMENT AND MANNER OF USING CON-
DUCTORS FOR TELEPHONIC AND TELEGRAPHIC PURPOSES."
PROVISIONAL SPECIFICATION left by the said Oliver Heaviside at the
Office of the Commissioners of Patents on the 6th April 1880.
OLIVER HEAVISIDE, of No. 3, Saint Augustine's Road, in the County of
Middlesex. "IMPROVEMENTS IN ELECTRICAL CONDUCTORS, AND IN THE ARRANGE-
MENT AND MANNER OF USING CONDUCTORS FOR TELEPHONIC AND TELEGRAPHIC
PURPOSES."
When a number of wires run parallel to one another, either suspended or other-
wise, any change in the current flowing in one wire causes currents in all the rest
by induction, and the effect may be so great as to seriously interfere with the
working of telephonic circuits, and to a less degree of ordinary telegraphic circuits
also.
It is a common practice to complete the circuit by means of a second wire instead
of the earth, and it is well known that the inductive interference is thereby reduced
in magnitude, the induced electro-motive forces in one wire cancelling those in the
other to a certain extent. The nearer the wires are brought together the less does
the inductive interference become, but it cannot be altogether eliminated in this
way, because the axes of the two wires cannot be made to coincide so that they
shall be both at the same distance from any disturbing wire.
My improvements have for object to obtain perfect protection, and to render a
circuit completely independent under all circumstances of external inductive
influences. For this purpose I use two insulated conductors for the circuit, and
place one of them inside the other; thus, one conductor may be a wire, and the
other a tube or sheath, thus forming a compound conductor consisting of a central
wire surrounded by an insulating covering, which is in its turn surrounded by a
conducting tube or sheath, which must also be insulated. When the tube and
inner wire are electrically connected at both ends of the line, as through apparatus
in the usual manner, the circuit as thus described is completely independent of
other circuits, and any number of such circuits, each containing an insulated tube

page_text: and inner wire, may be laid side by side and worked without any mutual inductive
interference, and without interference from other wires worked in ordinary
manners.
I also render circuits mutually independent in the following way, which does not
require the use of an insulated tube or sheath for the return current:-I employ
two wires for each circuit, one of which serves for return wire instead of the earth.
If 1 and 2 are the two wires forming one circuit, and 3 and 4 those forming the
other, I place the wires 1 and 2 at any convenient distance apart, and the wires 3
and 4 in any positions relative to 1 and 2, such that the induction according to
known laws between the circuits 1, 2, and 3, 4, is nil. There are many ways of
doing this, of which the following is one of the simplest:-The four wires are
placed parallel to one another, so that their centres are situated at the four corners
of a square upon a plane perpendicular to the axes-of-the-wires, and-the-two-wires-
at the opposite ends of one diagonal are paired to form one circuit, and the remaining
two wires are paired to form another. In consequence of the relative positions of
the four wires, and of the manner of pairing them, there will be no induction
between the two circuits.
It is not necessary for the centres of the four wires to form a square in the manner
described, for the circuits may have any other positions that make their mutual
induction nil. For instance, if the four wires 1, 2, 3, and 4 are placed parallel to
one another, and 1 and 2 are placed at any distance apart and paired to form one
circuit, while 3 is placed equidistant from 1 and 2, and 4 also equidistant from 1
and 2, and and 4 are paired to form a second circuit, then the mutual induction,
both static and dynamic of the two circuits 1, 2, and 3, 4, is nil as regards the
complete circuits. (The two wires 3 and 4 may be worked separately, using the
earth to complete their circuits, and they will be independent of the circuit 1, 2,
though not of one another. Similarly 1 and 2 may be worked separately, while
3 and 4 are paired).
The four wires may be suspended separately, and when there are a large number
of wires they may be arranged in groups of four, the four wires in every group
having proper positions, and being properly paired, as above described; or the four
wires may be insulated in any manner and laid side by side in proper positions,
preferably so that they form a square, and bound together for convenience, or
covered with a jacket, thus forming a cable containing four wires to be properly
paired to form two mutually independent circuits. The cables thus formed may be
suspended in the ordinary way.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Oliver Heaviside in the Great Seal Patent Office on the 6th
October 1880.
OLIVER HEAVISIDE, of No. 3, Saint Augustine's Road, in the County of 4
Middlesex. “IMPROVEMENTS IN ELECTRICAL CONDUCTORS, AND IN THE ARRANGE-
MENT AND MANNER OF USING CONDUCTORS FOR TELEPHONIC AND TELEGRAPHIC
PURPOSES."
When a number of wires run parallel to one another, either suspended or other-
wise, any change in the current flowing in one wire causes currents in all the rest

page_text: by induction, and the effect may be so great as to seriously interfere with the
working of telephonic circuits, and to a less degree of ordinary telegraphic circuits
also.
It is a common practice to complete the circuit by means of a second wire instead
of the earth, and it is well known that the inductive interference is thereby reduced
in magnitude, the induced electro-motive forces in one wire cancelling those in the
other to a certain extent. The nearer the wires are brought together the less docs.
the inductive interference become, but it cannot be altogether eliminated in this
way, because the axes of the two wires cannot be made to coincide so that they
shall be both at the same distance from any disturbing wire.
My improvements have for object to obtain perfect protection and to render a
circuit completely independent under all circumstances of external inductive
influences. For this purpose I use two insulated conductors for the circuit and
place one of them inside the other. Thus, one conductor may be a wire and the
other a tube or sheath, thus forming a compound conductor consisting of a central
wire surrounded by an insulating covering, which is in its turn surrounded by a
conducting tube or sheath which must also be insulated.
A suitable method of carrying out this part of my Invention is shown in
Figure 1 of the Drawing, which represents an enlarged section of the compound.
conductor. a is the conducting wire coated with gutta percha, india rubber, or
The core thus
other insulating material in the usual manner, as shewn at b.
formed is then coated with a thin layer of brass-tape, tin-foil, copper-foil, or a
sheathing of lead or other suitable conducting material c. The resulting sheathed
corc is then covered with gutta-percha, india-rubber, or other insulating material
to a convenient thickness, as shewn at d. If found desirable a wrapper may be
added for protection against injury. When the tube and inner wire are electrically
connected at both ends of the line, as through apparatus in the usual manner, the
circuit as thus described is completely independent of other circuits, and any
number of such circuits, each containing an insulated tube and inner wire may be
laid side by side and worked without any mutual inductive interference and
without interference from other wires worked in ordinary manners. Figures 2,
3, and 4 are diagrams showing the ways of joining up. In Figure 2 the compound
or slicathed conductor (shewn in section) is used for the whole distance, the wire a,
sheath c, and terminal apparatus e, e, forming a closed circuit excluding the carth.
But when only one end of a line is exposed to induction only that part need be
protected therefrom, as shewn in Figure 3, the unprotected portion being an
ordinary wire f, and the circuit completed by earthing either the wire a or
sheath c at one end of the single portion, and earthing the apparatus at the other
end. In Figure 4 both ends of the line are shewn protected, while the inter-
mediate portion f is not protected, earth connection being made to either wire or
sheath at both ends off, the Figure shewing earth connection to sheath.
I also render circuits mutually independent in the following way, which does
not require the use of an insulated tube or sheath for the return current:-I employ
two wires for each circuit, one of which serves for return wire instead of the carth.
If 1 and 2 are the two wires forming one circuit, and 3 and 4 those forming the
other, 1 place the wires 1 and 2 at any convenient distance apart, and the wires 3
and 4 in any positions relative to 1 and 2, such that the induction according to
known laws between the circuits 1, 2, and 3, 4, is nil. There are many ways of
doing this, of which the following, shewn in section in Figure 5, is one of the
simplest: The four wires 1, 2, 3, 4, are placed parallel to one another so that their
centres are situated at the four corners of a squaro upon a plano perpendicular to
the axes of the wires, and the two wires 1 and 2 at the opposite ends of one
diagonal are paired to form one circuit, as shown by the dotted lines, and the
remaining two wires 3 and 4 aro paired, as shewn by the dotted lines, to form
another circuit. In consequence of the relative positions of the four wires
and of the manner of pairing them, there will be no induction between the
two circuits.

page_text: It is not necessary for the centres of the four wires to form a square in the
manner described and shewn in Figure 5. For instance, if the four wires 1, 2, 3,
and 4 are placed parallel to one another, as represented in Figure 6, and wires 1
and 2 are placed at any distance apart, and paired to form one circuit, while wire 3
is placed equidistant from 1 and 2, and 4 also equidistant from 1 and 2; and 3
and 4 are paired to form a second circuit, then the mutual induction, both static
and dynamic, of the two circuits 1, 2, and 3, 4, is nil as regards the complete
circuits.
It will be understood that the two wires 3 and 4 may be worked separately,
using the earth to complete their circuits, and they will be independent of the
circuit 1, 2, though not of one another. Similarly 1 and 2 may be worked
separately, while 3 and 4 are paired.
The four wires may be suspended separately, and when there is a large number
of wires they may be arranged in groups of four, the four wires in every group
having proper positions-and-being properly-paired, as herein before described.
Or the four wires may be insulated in any manner, and laid side by side in
proper positious, preferably so that they form a square, and bound together for
convenience, or covered with a jacket g, thus forming a cable containing four wires,
to be properly paired to form two mutually independent circuits. The cables
thus formed may be suspended in the ordinary way. In Figure 7, 1, 2, 3, 4, aro
the wires to be paired, as shewn by dotted lines, in one insulating covering b
surrounded by wrapper g; and in Figure 8 the wires are separately insulated, h
being a central yarn.
It will be understood that I do not confine myself to the employment of four
wires. Any four wires in a cable suitably situated may be paired in this manner,
or there may be any number of groups of fours.
"By my improvements besides the neutralization of induction the advantage of
immunity from earth currents and leakage, caused by imperfect earth connections
and im ect conductivity of the earth, is obtained.
Having thus described the nature of my said Invention, and the best means
with which I acquainted for carrying the same into effect, I wish it to be
understood that I do not confine myself to the precise details herein laid down, as
the same may be varied without departing from the peculiar character of my
Invention, but what I do claim is,―
The improvements in electrical conductors, and in the arrangement of and
manner of using conductors for telephonic and telegraphic purposes, substantially
as hereinbefore described.
In witness whereof, I, the said Oliver Heaviside, have hereto set my hand
and seal, this Fourth day of October, in the year of our Lord One thousand
eight hundred and eighty
Witness,
G. F. REDFERN,
Patent Agent,
4, South St.,
Finsbury.
OLIVER HEAVISIDE. (L.S.)