IMPROVEMENTS IN ELECTRIC TELEGRAPHS
Year: 1874

page_text: PROVISIONAL SPECIFICATION left by William Robert Lake at the
Office of the Commissioners of Patents, with his Petition, on the
3rd June 1874. A communication from abroad by Luigi Vianisi, of
Messina, Italy.
I, WILLIAM ROBERT LAKE, of the Firm of Haseltine, Lake, & Co.,
Patent Agents, Southampton Buildings, London, do hereby declare the
nature of the said Invention for "IMPROVEMENTS IN ELECTRIC TELEGRAPHS,"
a communication, to be as follows:-
--
This Invention relates to electric telegraphs, by which messages are
transmitted in opposite directions simultaneously on the same wire.
The system of simultaneous transmission herein described is based on
the application of the following principles :-If one pole of an electro-
magnetic pile is made to communicate with a telegraph wire, and the
opposite pole of the same pile is connected with the corresponding pole
of a second pile consisting of fewer elements, when the other pole of
this second pile is put in communication with the electro-magnet of a
receiver connected with the earth, the current of the weaker pile is
neutralized, and there remains only the current of the stronger pile

page_text: diminished to the difference of the two opposite currents. The remaining
current of the stronger pile in passing through the weaker pile may have
a degree of intensity sufficient to develope the magnetism of the electro-
magnet of the receiver, where it has to pass in its course to the earth;
but when there is another conductor establishing communication
between the point where the two corresponding poles connect, and the
earth in effecting, by means of a rhcostat, a varying resistance in this
conductor, the current of the stronger pile can be divided over these two
conductors until the opposing current of the weaker pile becomes
neutralized, and that of the stronger pile becomes in like manner
neutralized in the branch where the two currents oppose each other; the
result being that no action is developed in the receiver.
When the current of the stronger pile of one station is opposed to
another current of the same polarity and of equal force of a corre-
sponding station, the currents of the stronger piles will be neutralized,
but the same will not be the case with the weaker piles, which will
continue to circulate independently of the others, and will act upon the
electro-magnets of the receiver which in this case will continue to
operate.
The communications of the stronger pile with the telegraph wire, and
those of the circuit of the weaker pile can at the same moment of time
be established, or can be broken by means of a particular arrangement of
the manipulator.
In applying another modification of the application of the herein-
before described principles, I have devised a second combination which
will afford equal advantages with the foregoing, and thus attain a
diminution in the number of the elements of the piles (or batterys)
requisite for the correspondence. This second combination will be
useful for long submarine cables. In the two corresponding stations a
pile composed of fewer elements is placed in communication with the
I wire that it shall not want for it in order to correspond with the normal
condition. Meanwhile this pile is completed by another pile with which
it is going to be connected at the corresponding station in such a
manner that both together establish the number of elements necessary to
transmission in the following manner:-At each of the two stations the
weaker piles have one of the poles (say for example the negative)
connected with the telegraph wire, in such a manner that the two
negative currents in a state of repose oppose each other on the wire, and

page_text: destroy themselves. When one station sends a current, the negative
pole of the weaker pile is detached from the wire and is replaced
by the positive pole of the other in such a manner that this pole acts
through the wire to connect itself with the negative of the other
station, thereby establishing one single pile of which one portion
finds itself in one and the other portion in the other of the two corre-
sponding stations. The current of this pile thus formed causes the
apparatus at the receiving station to operate. The union of these two
portions of the pile which thus are placed at the two stations, constitutes
the stronger pile of the transmitting station, which, as has just been
shown, neutralizes the current of the weaker pile, and has no action on
the clectro-magnets of the receiver. At the moment when the two
stations are transmitting, the positive current of the piles employed for
transmission is sent through the telegraph wire, and so long as these two
currents neutralize each other, for they are of the same polarity, the
action of the negative current of the same piles remains also neutralized
upon the weaker piles, which will develope their current that passes
through the interior circuit, and will cause the apparatus with which
they are in connection to operate.
As to the relations between the resistance of the circuits resulting
from the described combinations, the electro-motive force of the piles
and the intensity of the currents, I shall at present limit myself. to the
following general indications:-Supposing that it were required to give
to the rheostat a resistance equal to the normal resistance of the telegraph
wire on which it is desired to apply this system, it is necessary to
distinguish the two circuits, that is to say, that along which passes the
current of the weaker pile, and that along which passes the current of
the stronger pile, when making up the sum of the resistances, whether it
be of the one or of the other. When the total resistance of each one of
these two circuits is once known, it is necessary to employ in both an
electro-motive force proportioned to their respective resistance, in such a
manner that the intensity of the two currents may be nearly equal on
the two circuits.
It only remains in conclusion to observe that although with the
arrangement adopted by me sufficiently sensible return currents do not
result, yet whenever it is desired to eliminate these immediately, I have
found it advantageous to interpose a few elements (say) to the extent of
three or four surfaces, between the telegraph wire and the receiver,

page_text: with the positive pole towards the wire and the negative towards the
receiver.
The manipulator employed in my telegraph has a rectangular base
carrying a metallic lever rocking upon a pivot which rests upon a
support fixed upon the base. The said lever carries above and below its
point two pieces of insulating substance, upon which are fixed by
insulated screws upper and lower steel springs. The said lever has at its
extremities two appendages bent back at a right angle, and upon which
rest the said two springs. One of the said appendages is in metallic
contact with the lever, the other appendage is separated from it by an 1
insulated piece and performs no electric function, but serves simply to
maintain the upper spring in the same position as the lower spring.
When the lever of the manipulator is depressed, the lower spring is
brought in contact with the metallic contact block, and the other spring
with a screw fixed on a piece placed perpendicular to a small pillar.
These two springs simultaneously become detached from the right angled.
pieces or apparatus, and thus the lower spring remains insulated from
the lever. An adjusting screw serves to regulate the space that separates
the aforesaid lever. A cylindrical piece which plays upon a stop serves
to limit the oscillation of the lever by interposing a solid object to its
stroke. This manipulator has five metallic screw sockets, three of which
are fixed upon the front of the manipulator, the other two are placed one
on each side perpendicularly to the said lever. These sockets are connected,
the first with the lower spring, the second with the support and with the
lever, the third with the contact block, the fourth with the upper spring,
the fifth with the aforesaid small pillar with the perpendicular piece and
with the screw.
A modification of the foregoing construction of the manipulator
consists in a "Morse transmitter," to which has been added two small
lateral levers fixed by insulated pivots to the principal lever. When the
manipulator is at rest these lateral levers are supported by two stops
placed on the sides of the principal lever. At one point the contact
between the levers permits the passage of the current, which is
interrupted by an insulating picce, in such a manner that while the
manipulator is at rest the lateral lever has no communication with the
principle lever. To these lateral levers are attached two helical springs.
1
11

page_text: This pulley is attached to an adjustable piece which traverses the
principle lever having on its end a nut. By screwing or unscrewing this
screw the said adjustable piece and pulley may be raised or lowered and
caused to increase or diminish the tension of the helix. When the
principle lever is depressed the two small levers are moved with it,
thereby becoming detached from the stops and establishing a contact.
with the screws. A stop piece serves to limit the movement of the
lever.