IMPROVE- MENTS IN ELECTRIC TELEGRAPHS AND APPARATUS
Year: 1856

page_text: PROVISIONAL SPECIFICATION left by Charles William Siemens at the
Office of the Commissioners of Patents, with his Petition, on the 10th
September 1856.-A communication.
I, CHARLES WILLIAM SIEMENS, of John Street, Adelphi, in the County of
Middlesex, do hereby declare the nature of the said Invention for "IMPROVE-
MENTS IN ELECTRIC TELEGRAPHS AND APPARATUS," to be as follows:-
In various constructions of electric telegraphs transmitting instruments or
relays are employed. These instruments, while acted upon by an electric
current passing through a circuit, close or complete the connection of another
circuit. When the first electric current ceases, the transmitting instrument or
relay opens the second circuit by the action of a spring, or otherwise. I con-
struct transmitting instruments or relays in such manner, that when acted upon
by an electric current passing in one direction they close the second circuit, and
when acted upon by an electric current passing in the other direction they
open the second circuit; and on the electric current ceasing, the transmitting
instrument still retains its position, so that a momentary electric current in the
first circuit produces a permanent closing or opening of the second circuit.
I effect this object by placing the pole or poles of a moveable electro-magnet
between the opposite poles of two permanently magnetic steel or electro-
magnets. When no current is passing through the first circuit, and the
iron of the electro-magnet is in a central position, it is equally attracted by
both poles; but if it be moved towards either pole it will be more attracted by
that pole than by the other, and will consequently remain on that side, and per-
manently close or open the second circuit. When a momentary current in the
proper direction is passed through the first circuit, the electro-magnet is
repelled by the nearest pole and attracted by the farthest pole, and its position

page_text: is thus permanently reversed. I cause the iron of the electro-magnet to revolve
within a fixed coil. In lieu of employing two permanently magnetic magnets
as aforesaid, one magnet may be employed in conjunction with a spring or
weight, which is so adjusted as to balance the attraction of the magnet when
the iron of the electro-magnet is in a central position; the same effect is thus
produced. I employ these transmitting instruments or relays in conjunction
with Morse's writing apparatus or other telegraphic instruments worked by
relays. The momentary or transient currents in the line wire or first circuit
may be produced by any of the ordinary apparatus arranged so as to send
alternate currents in opposite directions, or by a magneto-electrical apparatus,
or by means of the following apparatus, which is capable of transmitting signals
simultaneously in both directions through the same line wire. This apparatus
is constructed for producing secondary currents in a coil of wire on an electro-
magnet, the primary coil of which is traversed by a current from a local battery.
One pole of the local battery is connected to one end of the primary coils
of two electro-magnets. The other ends of these coils are connected to one
contact piece placed near a moveable key, which is permanently connected to
the other pole of the local battery; by depressing the key a current is passed
through the primary coils of both electro-magnets. A secondary or induced
current is thus produced in the secondary coils of the electro-magnets. The
secondary coil of the first electro-magnet is connected at one end through
the coil of the relay to the line wire and at the other end to the earth.
The two ends of the secondary coil of the second electro-magnet are con-
nected to the two ends of another coil on the relay, and the parts are so
arranged that the current traversing this coil may be of equal power, and in
the opposite direction to that traversing the first coil of the relay. The second
current is adjusted by partially withdrawing or inserting the iron core in the
coil of the second electro-magnet; thus, when the key is depressed at one
station, the relay at that station is not affected, but a momentary current
passes along the line wire and works the relay at the distant station, and thus
communicates a signal. When the key is again allowed to rise, a reverse
current passes through the line wire and causes the relay to return to its first
position. When the key remains up it comes in contact with a contact piece
which is in communication with the earth, and the instrument is then adapted
for receiving signals from the distant station. If the keys at both stations are
simultaneously depressed, the two currents in the line wire meet and neutralize
each other, and the instruments at both stations are worked by the secondary
currents of their respective second electro-magnets.
The aforesaid mode of arranging the magnets of relays is also applicable to

page_text: instruments worked by a step-by-step motion. For this purpose, the per-
manent magnets and the moveable electro-magnet are arranged as herein-before
described, and the moveable electro-magnet carries a lever with two pauls or
clicks, which enter the teeth of a ratchet wheel carrying an index which points
to the letters or signals on a dial. The backs of the pauls are made of an
inclined or curved shape, and are controlled by stops, which are so adjusted as
to allow of their advancing the ratchet wheel, but to prevent the wheel from
overrunning. This step-by-step apparatus may be worked by the following
magneto-electrical apparatus, by which the power of several magnets may be
combined. I take a cylindrical bar of iron and cut two broad and deep lon-
gitudinal grooves in two opposite sides of the bar, and I wind a quantity
of insulated or coated wire in a longitudinal direction in these grooves.
The wire may be protected by brass covers, which complete the original
cylindrical form of of the bar. This bar is mounted upon a vertical axis, and
revolves between the poles of a series of permanent magnets, placed one above
another, and which may consist of steel bars fixed at one end to a flat iron bar,
and having grooves near their other ends to correspond with the form of the
aforesaid cylindrical bar. The cylindrical bar carries a pinion, which is driven
by a wheel on which is an index to point to the different signals. This wheel
is moved by hand, so as to bring the index opposite to the required letter or
signal. The cylindrical bar is thus made to revolve, and at each revolution
two successive electrical currents are produced in its coil in one direction, and
then two in the contrary direction. The effect may therefore be considered as
equivalent to one current in each direction at each revolution. One end of the
coil is constantly in connection with the line wire, and the other end with the
earth. The alternating currents thus sent through the line wire give motion
to the aforesaid step-by-step instrument at the distant station, and cause its
index to move round to the same letter or signal as that to which the index at
the first station had been moved by hand. This magneto-electrical apparatus
may be employed for working the relays first herein-before mentioned, and it
may then be made with a reciprocating motion, if more convenient. By apply
ing a commutator for directing the currents in one direction into one wire or
electrode and the reverse currents into the other wire or electrode, this
apparatus or machine may be employed for the same purposes as other
magneto-electric machines.