IMPROVE- MENTS IN ELECTRIC TELEGRAPH CONDUCTORS AND CABLES
Year: 1867

page_text: LETTERS PATENT to John Henry Johnson, of 17, Lincoln's Inn Fields,
in the County of. Middlesex, Gentleman, for the Invention of "IMPROVE-
MENTS IN ELECTRIC TELEGRAPH CONDUCTORS AND CABLES." A communication
from abroad by John Montgomery Batchelder, of Cambridge, Massa-
chusetts, United States of America.
PROVISIONAL SPECIFICATION left by the said John Henry Johnson
at the Office of the Commissioners of Patents, with his Petition, on the
26th January 1867.
I, JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of
Middlesex, Gentleman, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN ELECTRIC TELEGRAPH CONDUCTORS AND CABLES," a communi-
cation to me from abroad by John Montgomery Batchelder, of Cambridge,
Massachusetts, United States of America, to be as follows:-
This Invention relates to certain peculiar constructions of conductors for
electric telegraphs, whether intended as submarine cables or otherwise,
whereby kinking" is avoided, and greater pliability, elasticity, and strength
are obtained, combined with facility for giving any required proportion or
relation between the tensile strength and of the conducting power of the line
or cable.

page_text: The essential feature of the first portion of this Invention consists in the
manufacture of electric telegraph conductors by braiding or interlacing in
lieu of twisting together any desired number of wires made either of the same
metal or of two or more dissimilar metals, such, for example, as iron or steel
and copper; the iron or steel, although not such good conductors as the
copper, tend greatly in increase the tensile strength of the cable; two or more
of these braided conductors may be combined together to form a submarine
cable, each conductor being separately insulated, and the cable then made up
of a series of such braided conductors bound or held together in any con-
venient manner. When required to be suspended from posts for land
telegraphs, the braided conductors may be employed singly, and without an
insulating covering.
Another part of this Invention consists in covering or coating iron or steel
wire with a sufficiently thick coating of copper to form a conductor for
electricity; the compound wire thus obtained consisting, in fact, of a copper
conductor reinforced for the purpose of strength with a core of iron or steel.
The coating or covering may be accomplished by the well-known process of
electro-plating, and after the wire has been coated it should be subjecied
to the common process of wire drawing in order that the copper may be
hardened and receive a smooth surface or finish. A single wire or a series of
these wires combined together may be used as a conductor in telegraph circuits,
and connected with the instrument either at the termini of a line or at
intervals or stations upon the line.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said John Henry Johnson in the Great Seal Patent Office on the
26th July 1867.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of Middlesex,
Gentleman, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Paient, hearing date the Twenty-sixth day of January, in the year of our Lord
One thousand eight hundred and sixty-seven, in the thirtieth year of Her
reign, did, for Herself, Her heirs and successors. give and grant unto me, the
said John Henry Johnson. Her special license that I, the said John Henry
Johnson, my executors, administrators, and assigns, or such others as I, the said
John Henry Johnson, my executors, administrators, or assigns, should at

page_text: IN
any time agree with, and no others, from time to time and at all times thereafter
during the term therein expressed, should and lawfully might make, use,
exercise, and vend, within the United Kingdom of Great Britain and Ireland,
the Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS
ELECTRIC TELEGRAPH CONDUCTORS AND CABLES," being a communication to me from
abroad by John Montgomery Batchelder, of Cambridge, Massachusetts, United
States of America, upon the condition (amongst others) that I, the said John
Henry Johnson, my executors or administrators. by an instrument in writing
under my hand and seal, should particularly describe and ascertain the nature
of the said Invention, and in what manner the same was to be performed, and
cause the same to be filed in the Great Seal Patent Office within six calendar
months next and immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said John Henry Johnson, do hereby declare
the nature of the said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement, reference being had to the accompanying Drawings, and to the
letters and figures marked thereon, that is to say :-
The said Invention relates mainly to the construction of the metallic
conducting cord or wire of electric telegraphs, the same being used either
naked for air lines or coated with gutta percha, india-rubber, or with
Chatterton's or other insulating compounds for making cables for submarine
telegraphs.
One feature of the improvement consists in making the conductor of braided
wire, having any required number of strands; the braiding or involution of
the several wires makes a single conducior of any required strength, and
forms a metallic cord, not liable to kink, in which each of the strands is
subjected to a uniform strain, and the cord has no tendency to revolve axially
when under tension; it is also perfectly pliable and capable of sufficient
extension to prevent it from being too rigid during the process of covering or
while being placed in position for use. As it consists of small wires the
continuity of the whole cord or conductor is as certain as in the compound
twisted lines.
One of the most important features of the said Invention consists in the use
of different metals in the same braided conducior for special purposes, having
reference mainly to the formation of a cord or conductor in such a manner as
to give any required proportion or relation between its strength and conducting
power. The capacity for the passage of electricity through an iron wire being
one, that of copper wire of the same size is about seven. while the tensile
strength of iron wire is very much greater than that of copper wire.

page_text: In the improved conductor varying numbers of strands of iron and of copper
wire are employed, for example, two conductors A and B are made of nine
wires or strands each. A consists of six copper wires and three iron wires,
B consists of three copper and six iron wires; their proportional or relative
conducting power will be as follows:-
Thus the tensile strength of B as compared with A is in the proportion 15 to
12, or 5 to 4. If in the cord B I substitute six steel wires (which are
about twice as strong as iron wires) its strength as compared with A is as
twenty-seven to twelve.
These examples show that the strength and conducting power may be
established in any required proportion by the use in a braided cord of varying
numbers of wires composed of different metals. The combined wires of
different metals may be turned after braiding if deemed desirable.
The cord herein described and forming the conductor is made in a common
braiding machine in the manner now well known and in common use for
making round cordage, such as halyards and gun-lock lines.
Figure 1 of the annexed Sheet of Drawings represents a seven-wire braided
cord, four of the wires (tinted red) being of copper, and three (tinted blue)
of iron or steel; and Figure 2 is a similar braided cord composed of nine
wires, of which three are copper and six iron or steel.
The improvement relates, therefore, partly to a braided conductor and
partly to the use of wires or strands composing the same of different metals,
whether the same be used for submarine or for air lines of telegraphs. For
submarine cables it is proposed to make the braided conductor of copper and
iron, or of copper and steel wires, of about number eighteen or twenty by the
wire gauge, the total diameter of the single cord being about three-eighths or
half an inch; this is coated with one or more coats of india-rubber, gutta percha,
Chatterton's or other insulating compound, protected and strengthened on the
exterior if necessary. The number of copper strands to be braided in with

page_text: the iron ones will depend upon the length of the cable, a sufficient number
being used to ensure the passage of the required amount of electricity, the
iron or steel wires which prevent strain upon the copper wires serving also
as conductors, although in a less degree. For long lines, in which it is
desirable that the length of each of the copper wires should not be much
increased by the process of braiding, the delivery of the wire to the braiding
machine is rapid as compared with the "braiding or crossing of the strands,
thus forming a compound cord held together by the interlacing or crossing of
the strands at any required intervals, say, from half an inch to two or three
inches, the wires at intermediate points being parallel with each other.
The compound braided wire composed of two or more metals may be used
as a single conductor in a cable, or several compound conductors may be used,
cach of which is insulated separately, and the cable then made up of a series
of them bound or held together in any convenient manner. The conductor
thus formed has a sufficient degree of elasticity, is free from twist, not liable
to kink, and is capable of any required amount of difference between its
strength and conducting power.
Another feature in this Invention consists in the use of an iron or steel wire
covered with copper, the copper being used for its superior conductivity and
lightness, and the iron or steel particularly for tensile strength. This copper
covering upon the iron or steel wire may be made by casting and drawing, or
it may be deposited upon the iron or steel wire by the process of electro-
plating, the wire being immersed in a solution of the sulphate or other salt of
copper, this deposit or coating being of sufficient thickness for the purpose of
conductivity, and not a mere wash on the surface of the iron wire to prevent
corrosion. After the wire is coated with copper it should be subjected to the
common process of wire drawing in order that the copper may be hardened
and receive a smooth surface or finish. A single wire made of the two metals
as above described may be used as a conductor, or several of them may be
braided or twisted together to form a single conductor.
In addition to the formation or construction of a conducior composed of
two metals. either by braiding, twisting, covering. or otherwise combining
them to insure the required strength and conducting capacity, this Invention
consists in the employment of such conductors in a telegraph circuit, and in
their combination and connection with the instruments or apparatus used for
sending or receiving electric signals, cither of the termini of the line of electric
telegraph or at intervals or stations upon the line. Such a circuit is repre-
sented in plan upon the Drawing at Figure 3. A denotes the battery or
source of electricity; B, the magnet; C, the armature; D, the conducting

page_text: wire; E, the finger key; F, F, the ground connections, the whole making
up the circuit, as will be readily understood. The compound wire D is
represented partly in section to show its iron or steel core d.
The advantage of employing a conductor of this kind is obvious, for on
account of the superior conducting power of copper I obtain in a compound
wire possessing an equal tensile strength with the common telegraph wire
now in use double the conductivity, the compound wire being at the same
time very much lighter than the common wire; or I may obtain at an equal
cost and with equal conductivity a compound wire weighing not more than
half the common wire now in use.
The relative values of iron wire of Nos. 8 and 9 (Birmingham gauge), and
of the compound conductor strengthened as herein set forth, as to weight,
tensile strength, and conductivity will be understood from the following
table-
Weight per mile
Tensile strength
wire.
No, 11 iron
wire covered
with copper to
enlarge it to
No,, 9.
No. 11 stel
wire enlarged to
No. 9 with
copper.
No/, 12 steel
wire enlarged ta
No. 10 with
copper.
No .. 8 iron
No. 9 iran
wire.
"
381
307
321
322
264
-
*1838
1479
1326
2049
1686
34
28
75
80
56
Proportional value
as a conducior
Having now described and particularly ascertained the nature of the said
Invention, and the manner in which the same is or may be used or carried
into effect, I would observe in conclusion that what I consider to be novel
and original and therefore claim as the Invention secured to me by the
herein-before in part recited Letters Patent is,-
Firstly, the construction and use of electric telegraph conductors composed
of braided or interlaced wires of two, or more dissimilar metals, one wire or
series of wires serving mainly as conductors of clectricity, and the others
imparting the required strength to the conductor.
Secondly, the application and use of a copper conductor reinforced for the
purpose of strength with a core of iron or steel.
Thirdly, the application and use of a compound conductor composed either
of iron and copper wires braided or twisted together, or of a series of copper-
covered iron wires braided or twisted together, or a copper conductor having
a core of iron or steel in combination with the instruments, making up with
the conducting wire an electric telegraph circuit, as herein-before described,

page_text: Fourthly, the combination in a submarine telegraph cable of the braided
conducting wires, or the copper covered iron or steel wires, and their non-
conducting or insulating covering, as herein-before described.
In witness whereof, I, the said John Henry Johnson, have to this my
Specification set my hand and seal, the Twenty-sixth day of July. One
thousand eight hundred and sixty-seven.
J. HENRY JOHNSON. (...)