IMPROVEMENTS IN INSULATING AND SUPPORTING TELEGRAPH LINE WIRES
Year: 1863

page_text: LETTERS PATENT to Charles William Siemens, of No. 3, Great George
Street, Westminster, in the County of Middlesex, for the Invention of
PROVISIONAL SPECIFICATION left by the said Charles William Siemens
at the Office of the Commissioners of Patents, with his Petition, on the
20th February 1863.
I, CHARLES WILLIAM SIEMENS, 'of No. 3, Great George Street, West-
minster, in the County of Middlesex, do hereby declare the nature of the
said Invention for "IMPROVEMENTS IN INSULATING AND SUPPORTING TELEGRAPH
LINE WIRES," to be as follows:-
Telegraph line wire is sometimes covered throughout its length with an
insulating material, and at other times the uncovered wire is suspended in
the air from poles, with insulating supports for the wire attached to the same;
in the latter case the atmospheric air is the insulating medium surrounding the
conductor.
In forming a continuous insulating covering upon a conducting wire, I
employ the natural juice or milk extracted from the india-rubber or gutta
percha trees, or varieties of the same. For this purpose I send out to the
countries where these trees abound metallic or other vessels capable of being
sealed hermetically; these vessels being attached to the tree receive the

page_text: juice therefrom through a connecting tube, as far as practicable under
exclusion from contact with the surrounding atmosphere. These vessels,
when filled with juice, are hermetically closed by means of a screw stopper or
otherwise, and are then shipped to this country. I prefer to give to these
vessels a rectangular prismatic form, with a screw stopper at one end for
convenience of stowage.
In effecting insulating coverings by means of these juices, which will be
found to remain entirely liquid in the sealed vessels, I prefer to proceed in the
following manner :-I cover the wire first with a layer of silk, cotton, or
other fibrous material in the usual way; the wire thus covered is passed
through or soaked in a bath of the juice, and rising slowly from the bath, it
passes through an air flue or shaft of very considerable height, which is main-
tained at a temperature of from 100 to 300 degrees Fah. either by external
application of heat or by a continuous supply of heated air from a stove.
Under the influence of the heated air, the film of juice adhering to the wire
becomes rapidly dried and consolidated. Passing over a pulley at the top of
the heated air shaft, the wire descends, passes at the bottom over another
pulley immersed in the juice, and again ascends through the same or another air
shaft. In this manner the wire may receive any number of thin coats of india-
rubber or gutta percha, or of both materials combined. At intervals the wire
may be passed with advantage through a solution of shellac, or colodion, or
other insulating substance. The covered wire may also receive at intervals
additional coats of fibrous material or of other insulating material, such as
india-rubber or gutta percha put on by any of the known processes. It is
not necessary to provide the wire in the first instance with a covering of
fibrous material, although I prefer to do so generally. In order to
increase the thickness of each covering film of india-rubber or gutta percha, I
sometimes subject the natural juice, previous to its application, to a process
of evaporation. This is best effected by gentle application of heat under the
influence of a partial vacuum.
In suspending telegraphic line wire, in the air, I prefer to use an insulator
consisting of an inverted bell of porcelain or hardened india-rubber, which is
cemented into an inverted cup of cast iron to protect the same against rain
and injury. A stalk of steel or iron with enamelled surface is cemented into
the insulating inverted cup, being turned up at the end, or provided with other
means of fastening or supporting the line wire. The cast-iron protecting cup
has an arm terminating in a socket, the axis of which is parallel to that of
the cup, and which is slipped over the post or main support. Two insu-
lators may be united, to the same socket to support a wire on either side of

page_text: the post. A set screw or key may be employed for fastening or steadying the
socket on the post.
The posts hitherto most employed are of wood and iron, structures with or
without wood tops have frequently been used. The wooden posts do not
afford a permanent support to the insulated wire, being subject to decay, and
the iron posts hitherto employed are very costly and difficult to transport. In
order to meet these difficulties, I construct telegraph posts, by preference, of
three parts to be carried separately, and to be put together on the spot. The
part of the post which is buried in the ground I prefer to construct of a
dished plate of wrought iron, combining lightness with rigidity in a remarkable
degree. A cast-iron pipe is fixed by bolts or otherwise to this foot plate at or
near the middle, which pipe rises considerably above the ground line, and
terminates in a socket to receive the upper portion of the post, which consists
of a conical tube of wrought iron welded together longitudinally, combining
strength with lightness and compactness in a high degree. This tube is
fastened in the socket by means of wedges, and by pouring in a cement con-
sisting, by preference, of sulphur with an admixture of oxide of zinc or other
metallic oxide. The wrought-iron tube may be surmounted by a metallic
rod for the discharge of atmospheric electricity into the ground. Both the
lightening discharger and the stalk of one or more insulators may be dropped
side by side into the top of the wrought-iron conical tube, and secured by a
wedge, or in any other suitable manner. Each of the three essential parts
composing this post is of such moderate size and weight as to admit of con-
venient transport, which is of great importance in constructing telegraph lines
through uncultivated countries. Each part of this post may be varied in form;
instead of a dished plate a straight plate of increased thickness and weight
may be used to form the foot, or a heavier cast-iron plate may be used, or a
plank or cross of timber, or a block of stone may be employed in its stead.
The lower cast-iron portion of the post may be made cylindrical or slightly
conical, diminishing upwards. It is obvious that the foot plate may be cast
in one piece with the lower part of the post, but this arrangement could only
be applied where no difficulties of transport would arise, and under any cir-
cumstances, I much prefer making the same a separate piece.
Instead of a conical welded wrought-iron tube to form the upper portion of
the post, a cylindrical wrought-iron tube may be used; but I decidedly prefer
to employ a tapering tube, diminishing upwards in such a ratio as approxi-
mately to constitute a lever of equal strength at every point. The hollow
space within the tube may be filled with sand, earth, or cement, or the
wrought-iron tube forming the upper part may be rolled or drawn with and

page_text: upon a core of sand, which in the process of rolling or drawing will con-
solidate in consequence of the heat of the furnace employed, thus forming a
solid core.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Charles William Siemens in the Great Seal Patent Office
on the 19th August 1863.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, CHARLES
WILLIAM SIEMENS, of No. 3, Great George Street, Westminster, in the
County of Middlesex, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twentieth day of February in the year of our Lord
One thousand eight hundred and sixty-three, in the twenty-sixth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said Charles William Siemens, Her special licence that I, the said Charles
William Siemens, my executors, administrators, and assigns, or such others
as I, the said Charles William Siemens, my executors,, administrators, and
assigns, should at 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 IN INSULATING AND SUPPORTING TELEGRAPH LINE WIRES," upon
the condition (amongst others) that I, the said Charles William Siemens,
my executors or administrators, by an instrument in writing under my, or
their, or one of their hands and seals, should particularly describe and ascer-
tain 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 Charles William Siemens,, do hereby
declare the nature of the said Invention, and in what manner. the same is
to be performed, to be particularly described and ascertained in and by the
following statement thereof, reference being had to the accompanying, Drawing,
and to the figures and letters marked thereon (that is to say):
This Invention consists of improvements in insulating and supporting
telegraph line wires. Telegraph line wire. is sometimes covered throughout.
its length with an insulating material, and at other times is suspended in the

page_text: air from poles with insulating supports for the wire attached to the same; in
the latter case the atmospheric air is the insulating medium surrounding the
conductor.
In forming a continuous insulating covering upon a conducting wire, I
employ the juice or milk extracted from the india-rubber or gutta percha
trees or varieties of the same. For this purpose I send out to the countries
where these trees abound metallic or other vessels capable of being her-
metically sealed; these vessels being attached to the tree receive the juice
therefrom through a connecting tube, as far as is practicable under exclusion
from contact with the surrounding air. These vessels, when filled with juice,
are hermetically closed by means of a screw stopper or otherwise, and are then
shipped to this country. I prefer to give to these vessels a rectangular prismatic
form with a screw stopper at one end for convenience of stowage.
In effecting insulating coverings by means of these juices, which will be
found to remain entirely liquid in the sealed vessels, I prefer to proceed in
the following manner :-I cover the naked wire or strand of wires first with a
layer of silk, cotton, or other fibrous material in the usual way; the wire thus
covered is passed through or soaked in a bath of the juice, and is slowly raised
from the same, and drawn up through an air flue or shaft of considerable
height, which is maintained at a temperature of from 100° to 300° Fahrenheit,
either by the external application of heat, or by a continuous supply of heated
air from a stove. An arrangement for this purpose is shewn at Figures 1 to 3
on the accompanying Drawing.
Figure 1 shews a transverse section of the same on line X, X; Figure 2;
Figure 2 shews a longitudinal section on line Y, Y, Figure 1; Figure 3 shews
a sectional plan on line Z, Z, Figure 2. The same letters of reference indicate
the same parts in each of the Figures.
A is a broad brick shaft with the hot-air flues B, B', on each side; C, C',
are two stoves for heating the same; a series of pullies D is placed on an axle
at the top of the shaft, and a second series D' is so arranged at the bottom
that the pullies can be submerged in a bath E, containing the juice of the
india-rubber or gutta percha tree, or each pulley may be placed in a separate
bath. The wire is lead into the shaft over the guide pulley d, and dips imme-
diately into the bath E, by which it becomes covered with juice; it then rises
up the shaft A, where, under the influence of the heated air, the film of juice
adhering to the covering of the wire on leaving the bath becomes rapidly con-
solidated and dry. The wire is passed over one of the top pulleys and down
again into the bath, by which it receives a second film of juice, which dries in
the same way, as the wire again passes up the shaft, and so on, till the wire

page_text: has got a sufficient number of coatings, when it passes away over the pulley d'.
Instead of one large bath of india-rubber juice or gutta percha juice alone,
these two substances may be mixed with advantage, or a number of small
baths containing alternately gutta percha and india-rubber juice may be sub-
stituted, so that the wire would receive alternate coatings of these substances.
After being coated with a series of films of one or both of these juices, the wire
might be spun over with a coating or coatings of fibrous material, or covered
with insulating material, such as india-rubber or gutta percha, by any of the
already known and applied means. It is not absolutely necessary to provide
the wire in the first instance with a covering of fibrous materials, but I prefer
to do so.
In covering a strand of wire with the juices I sometimes previously lay
threads of fibrous material helically between the wires composing the strand.
I have also applied with advantage the above-described means of coating with
india-rubber or gutta percha juice in the manufacture of hempen or other
cables for submarine telegraph lines. For this purpose I pass the core after
it has been spun once round with hemp or other fibrous material in one direc-
tion through a bath of india-rubber or gutta percha juice, and I then spin the
second layer of hemp or other fibrous material in the reverse direction before
the juice has become consolidated and dry, or I let a stream of the juice pass
upon the wire when once covered and before the second covering is applied.
The saturated fibrous covering of great tenacity so formed may then, before
the juice has had time to dry, with advantage be covered with a metallic
laminous sheathing, as described in the Specification to certain Letters Patent
granted to me and bearing date the 9th of January 1862 (No. 59), after
which the cable so formed must be exposed for some time to atmospheric
influence, in order that the india-rubber or gutta percha juice may become
perfectly consolidated or indurated. In order to increase the thickness of the
single films of india-rubber or gutta percha, I sometimes subject the juice to a
process of evaporation. This is best effected by the application of a moderate
heat under a partial vacuum.
In suspending telegraph line wires in the air I prefer to use an insulator
consisting of an inverted bell of porcelain or hardened india-rubber or ebonite,
which is cemented into an inverted cup of cast iron to protect the same from
rain and injury, which cup may be either painted, galvanized, or enamelled.
An iron or steel stalk, the surface of which is either enamelled or covered
with ebonite or hornified india-rubber as far as it will be exposed to the
atmosphere, is cemented into the inverted insulating cup and turned up at the
lower end, or provided with other means for supporting or fixing the line wire.

page_text: The cast-iron protecting cup is furnished with an arm terminating in a socket,
the axis of which is parallel to that of the cup, and which is slipped over the
post or main support; or in place of a socket I form a curved flange at the
end of the arm, fitting partly round the post, against which it is firmly secured
by means of a horse-shoe strap passing over it and through an iron saddle on
the opposite side of the post, where it is screwed up, as shewn in section and
plan at Figures 10 and 11, where F is the inverted bell of porcelain or
hardened india-rubber; H, the inverted cup of cast iron; I, the enamelled
J, the arm; J', the flange to the same; K, the strap; and L, the
saddle piece.
stalk;
Two such insulators may be formed on the same bracket to support a wire
on each side of the post, as is shewn at M in Figures 4 to 7. In this case
either a set screw m or a wedge may be employed for fastening or steadying
the bracket on the post. The posts mostly hitherto employed have been of
wood, and iron structures with or without wooden tops have also frequently
been used. The wooden posts do not afford a durable support to the insulated
wire as, they are subject to decay, and the iron posts hitherto employed are
very costly and difficult to transport. In order to meet these difficulties I
construct telegraph posts of three parts, to be carried separately and put
together on the spot. The part of the post which is buried in the ground I
prefer to construct of a dished plate of wrought iron, combining lightness with
rigidity in a remarkable degree. A cast-iron pipe is fixed by bolts or other-
wise to this foot plate at or near the middle, which pipe rises considerably
above the ground line and terminates in a socket to receive the upper portion
of the post, which consists of a conical tube of wrought iron welded together
longitudinally, combining strength with lightness and compactness in a high
degree. This tube is fastened in the socket by pouring in a cement consisting
by preference of sulphur.with an admixture of oxide of zinc or other metallic
oxide. The wrought-iron tube may be surmounted by a metallic rod for the
discharge of atmospheric electricity into the ground. Both the lightning
discharger and. the stalk of one or more insulators may be dropped side by
side into the top of the wrought iron conical tube, and be secured by a wedge
or in any other suitable manner. Each of the three essential parts composing
this post is of such moderate size and weight as to admit of convenient
transport, which is of great importance in constructing telegraph lines through
uncultivated countries.
Figures 4 and 5 shew a sectional elevation and a plan of this construction
of telegraph posts. N is the dished plate; O is the cast-iron socket attached
thereto, and P is the conical wrought-iron tube; Q is the lightning conductor

page_text: formed with a loop at the top, through which a wire passes connecting al
the posts with each other, so as to discharge simultaneously through al
the posts.
.
I also employ some modifications of the same principle of construction
Figures 6 and 7 shew a sectional elevation and a plan of one of these modifi
cations, in which I employ as before a dished or buckled plate of wrough
iron N, but instead of bolting. this immediately to the foot of the tube I bol
it to the flange of a cylindrical cast-iron socket R, into which I cement the
lower end of a cylindrical wrought-iron tube O¹. Inside the latter, near the
upper end, I rivet an inverted iron cup o. The upper tube P. I make, as
before, conical and of wrought iron; its lower end rests on the bottom of the
iron cup o. I pass a cast-iron collar or boss p over the upper or conical tube
and press it down by hammering or otherwise until it rests on the top edge of
the lower tube. The joint is then completed by pouring fluid cement through
a hole in the collar.
A second modification, shewn in part sectional elevation and plan at
Figures 8 and 9, consists in connecting the tube O¹ to the foot plate N, by
means of a cast-iron collar S bolted on to the latter, the bottom of the
wrought-iron tube being hammered outwards so as to form a flange upon
which the collar presses.
Each part of this post may be further varied in form. Instead of a dished
plate a straight wrought-iron plate of increased thickness and weight may be
used to form the foot, or a heavier cast-iron plate may be employed, or a
plank or cross of wood or a block of stone may be made use of in its stead.
But I generally prefer the arrangement as shewn, on account of its combining
lightness with rigidity in the highest degree. The lower cast-iron portion of
the post may be made cylindrical or slightly conical, diminishing upwards.
Instead of a conical welded wrought-iron tube to form the upper portion of
the post, a cylindrical wrought-iron tube may be used, but I decidedly prefer
to employ a tapering tube, diminishing upwards in such a ratio as approxi-
mately to constitute a lever of equal strength at every point. The hollow
space within the tube may be filled up with sand, earth, or cement, or the
wrought-iron tube forming the upper part may be rolled or drawn with and
upon a core of sand, which, in the process of rolling or drawing, will con-
solidate in consequence of the heat of the furnace employed, thus forming a
solid core.
Having now described the nature of this Invention, and the best means I
am acquainted with of performing the same, I wish it to be understood that
what I claim is,-

page_text: Firstly, the employment of the juice or milk of the india-rubber and gutta
percha trees, and varieties of the same for coating electric telegraph line wires
or cables.
Secondly, effecting one or more coats of india-rubber or gutta percha, either
alternately or combined, upon electric telegraph line wires by passing the wire
to be so coated successively through a bath containing the juice or juices of
the india-rubber and gutta percha trees, and a shaft containing heated air or
gases, to consolidate or indurate the covering; also the combination of such
successive coats with layers or coats of insulating material applied in any
known manner.
Thirdly, effecting a tenacious covering to insulated telegraph line wire
by saturating the fibrous material employed in forming the same with the
juice or milk of the india-rubber or gutta percha trees, in the manner as
herein-before described.
Fourthly, the construction and use of posts or supports to electric telegraph.
line wires composed of a foundation plate of cast or wrought iron, or equivalents
for the same, to which is attached by bolts or otherwise a pipe or socket of
cast or wrought iron, rising to some height above the ground, and receiving in
its upper end a conical or cylindrical welded wrought-iron tube cemented into
the same, and carrying the insulating supports for the line wires, substantially
as herein-before described with reference to the accompanying Drawing.
Fifthly, the construction of insulating supports for suspending the line wire
or line wires from posts, as herein-before described with reference to the
accompanying Drawing.
In witness whereof, I, the said Charles William Siemens, have here-
unto set my hand and seal, this Fifteenth day of August, in the year
of our Lord One thousand eight hundred and sixty-three.
Witness,
THO. TAYLOR,
20, Southampton Buildings,
Chancery Lane.
C. W. SIEMENS. (L.S.)