IM- PROVEMENTS IN ELECTRIC TELEGRAPHS
Year: 1858

page_text: PROVISIONAL SPECIFICATION left by Charles William Siemens at the
Office of the Commissioners of Patents, with his Petition, on the 30th
September 1858.-Partly a communcation from Ernst Werner Siemens,
of Berlin, Prussia.
I, CHARLES WILLIAM SIEMENS, of John Street, Adelphi, in the County
of Middlesex, do hereby declare the nature of the said Invention for "IM-
PROVEMENTS IN ELECTRIC TELEGRAPHS," to be as follows:-
The line wire of an electric telegraph is frequently laid in the earth or in
the water in some parts of its course, and suspended in the air in other parts
of its course, and the comparative perfection and durability of its insulation in
every part are matters of the first importance. It is also necessary to
construct the signalling or transmitting and receiving instruments so as to act
with rapidity and certainty, and with small electric power, and also to render
the action of the battery as constant as possible. The ordinary wooden posts
employed for suspending line wire are liable to decay, and are sometimes
blown down by the wind, and the metallic posts which have been proposed
have been expensive in construction, while the gutta percha covering of
submarine or subterranean line wire is frequently porous and defective, and
allows a great portion of the electric current to escape. The suspended line
wires are also subject to disturbance by atmospheric electricity. The present.
Invention is intended to remedy or reduce these defects.
For the suspended line wire I employ metallic posts formed of three-
iron or steel rods, fastened together in the following manner:-The lower ends.
of the rods are bent and passed through holes in a ring or frame of angle iron,
and secured by keys or wedges between the rods and the angle iron; the.

page_text: upper ends are bent, and enter holes or recesses in a piece of iron pipe, or a
cylindrical or conical piece of wood, and are secured by an iron ring driven
down upon them. In order to give stiffness to the post, one or more lateral
stays or supports are introduced between the rods. Each lateral support
consists of three horizontal pieces of square or other rod, with their ends bent
to such an angle as to lie parallel with the main rods, to which they are
secured by rings or short tubes, which had been previously slipped over the
main rods. A wedge driven in between the ends of the stay rods fixes them
firmly. As the chief corrosion of these posts will take place at the level of the
ground, I propose to protect that portion of the main rods by means of short
Jengths of iron or other tube slipped over them, or put on hot, and shrunk on.
The iron work may be protected by heating it and immersing it in tar, or
by painting or galvanizing it. The insulators to be used with these posts may
be similar in construction to those described in the Specification of certain
former Letters Patent granted to me, and bearing date the Twenty-fifth day of
February 1854. I attach them to the posts by forming the insulator with a
curved cast-iron flange, which fits the posts, and has one or more projections
entering holes in the post, to which it is secured by an iron ring driven over
both. At the stretching posts, the insulating stalk terminates in an oblong
plate which tapers to the ends, and to which the wires are secured by cramps
or rings, so that the tension on the wire may tend to tighten the fixing. I
prefer to place this plate or bar so as to pass under and support the wire for
some distance beyond the fixing, so that the oscillations of the wire may not
act so immediately on the point of suspension.
I fasten a metallic stud on each post, to which, or to the metallic post itself,
I suspend a wire above the insulated telegraph wire or wires; this upper wire
receives and discharges lightning, and other disturbing electric influences of
the atmosphere, and causes the telegraphic instruments to work with greater
regularity; the ordinary lightning dischargers are not then required. The
suspended line wire may be plain or galvanized, but when it descends into the
water or the earth, it is necessary to surround it with a waterproof covering,
which is generally effected by passing the wire through the centre or axis of
a die through which plastic gutta percha is forced at the same time; I apply
the insulating and waterproof medium in the following manner, and I prefer
to employ caoutchouc or india-rubber, but gutta percha and other resinous
substances or compositions may be applied in the same manner :-
I employ two or more sets of metallic rollers, each set consisting of four
rollers, revolving in contact or in close proximity to each other, and which
may be called A, B, C, and D; the two rollers B and C have each a semi-

page_text: circular groove of the intended diameter of the covered wire, and the two
rollers A and D carry each a semicircular bead of the diameter of the wire to
be coated, and entering concentrically into the grooves of the rollers B and C
respectively. Two hoppers are provided to fit the rollers A and B and the
rollers C and D respectively, which hoppers are filled with caoutchouc or other
suitable insulating substance in a plastic state. The wire to be coated is
guided through the centre of the circular aperture formed by the junction of
the grooves of the rollers B and C, and is drawn forward at the rate
of the circumferential velocity of the rollers. On giving motion to the
machine, two semicircular bands or semi-tubes of caoutchouc or other
insulating material employed are produced between the rollers A, B, and C, D,
which two bands unite between the rollers B, C, and encompass the wire to be
coated. The coated wire then passes through a second set of rollers similarly
arranged, by which a second layer of caoutchouc or other insulator is applied,
so as to break joint with the first layer, or in such manner that the joints may
not coincide with those of the first layer. In a similar manner, a third and
fourth coating, or any required number of coatings may be applied. In order
to insure adhesion between the different coatings, and between the wire and
the first coating, and also to improve the insulation of the wire, it may be
passed at intervals through solutions of shellac, collodion, gutta percha,
caoutchouc, or other insulating substance; or it may be moistened with
naptha or other solvent to cement the successive coatings. In order to give
strength and protection to the coated wire, and at the same time to add to the
thickness of the insulating coating, I cover it with spiral strands of hemp or
other textile material, saturated previously with asphalte or other resinous
substance. A second similar covering is then applied with the lay or twist in
the opposite direction. The cable thus formed is passed through a heated
chamber, and then through a pair or pairs of grooved rollers, so as to compress
all the layers together; the coating with fibrous material and compressing
may be repeated, and the cable may be passed through a solution of hard
varnish, or may receive a thin coating of gutta percha, or other waterproof
material. Instead of single wires, strands of wires may be employed; several
strands or wires may be coated separately, as herein-before described, and then
united under one general insulating covering in a similar manner, the forms
of the grooves or beads on the rollers being varied when necessary."
When the whole or any large portion of the line wire is under water or
under ground, it acts like a Leyden jar, and receives a charge of electricity,
which interferes to a considerable extent with the working of the ordinary
instruments. A more powerful charge is accumulated when the connection

page_text: with the source of electricity is prolonged than when it is only momentary;
thus, when Morse's instruments or similar instruments are used, and which
produce signals by various combinations of dots and strokes produced by the
passage of a perforated strip of paper, the wire receives a stronger charge in
producing the strokes than in producing the dots; and this variation interferes
prejudicially with the action of the instruments. I obviate this defect by
making two or more perforations very close together, in lieu of one long slot
or perforation, and a second row of perforations, by means of which the charge
of the wire is reversed or discharged after the passage of each single or com-
pound perforation. I also prefer to make the discharging perforation which
follows a compound perforation, longer than that which follows a single
perforation. The intensity or degree of charge thus given to the wire is much
more uniform, and the action of the instruments is more uniform and certain.
The paper is perforated by a machine somewhat similar to that described in
the Specification of certain Letters Patent granted to me, and bearing date
the Eighth day of November, One thousand eight hundred and fifty-four.
By using a delicate and sensitive receiving instrument relays may be
dispensed with; and by employing a constant battery, the whole apparatus
acquires great certainty of action. I construct a receiving instrument some-
what similar in principle to Morse's instrument, and constructed in the follow-
ing manner -A strip of paper is drawn, by clock work or otherwise, in close
proximity, but not in contact, with a smooth rod of steel or other suitable
material, round which passes a cord or band which is carried round a roller,
and runs in contact with an inked roller, or is otherwise applied with colouring
material, and is kept tight by a roller and spring, or otherwise. The paper is
pressed against the cord or band, as it passes round the rod, by an arm moved
by the electro-magret or coil of the receiving instrument, and the dots or
marks are thus marked on it.
I construct a constant battery adapted for working the telegraphs, by
placing a copper plate on a layer of coarse sand or gravel at the bottom of a
jar, and carrying the conducting wire up inside a glass cylinder containing
crystals of sulphate of copper. The space above the copper plate and round
the glass cylinder is filled with sawdust or other porous material, on which
is placed a zinc plate. This porous material is wetted with a solution of
chloride of zinc, or salt, or acidulated water, or similar exciting liquid.