Year: 1896

page_text: being date of first Foreign Application (in 12th Sept., 1895
United States of America),
Date of Application (in United Kingdom), 28th Jan., 1896
Complete Specification Left, 28th Jan., 1896-Accepted, 2nd Jan., 1897
Date of Application (in United Kingdom), 28th Jan., 1896
Complete Specification Left, 28th Jan., 1896-Accepted, 2nd Jan., 1897
1. THOMAS BULLITT DIXON, a citizen of the United States of America,
residing at Henderson, County of Henderson, State Kentucky, United States of
America, do hereby declare the nature of this invention and in what minner
the same is to be performed, to be particularly described and ascertained in and
by the following statement :-
My invention relates to systems of multiplex telegraphy whereby two or more
distinct and separate messages are tran-mitted over a single line wire, by which
I ain enabled to reduce the number of line batteries employed for transmitting
messages, the number of line batteries required for transmitting messages in one
direction being less by one than the number of transmitters employed for that
direction, so that the current potential in the line con luctor need never be as high
as has been inevitable for transmitting the same number of messages in former
systems of telegraphy, which require a separate battery for each transmitter. In
former systems, requiring a separate battery for each transmitter, when all of the
batteries are put to the line current potential becomes so high as to interfere
seriously with the operation of sextuplex systems, because of the leakage of current
and other well known objections, and practically to prevent their use as well as to
prevent the use of systems transmitting a greater number of messages than six.
By my invention I am able to operate a sextuplex system with no greater number
of line batteries and no greater potential in the line than is employed with
quadruplex systems, and to operate a quadruplex system with no greater current
potential than is used for duplex systems. I am also able to simplify the receiving
mechanism required in the system over that shown in my above mentioned
patent.
My invention consists in the novel means whereby I am enabled to transmit
messages with a less number of line batteries than there are transmitters, in the
novel means employed for operating the pole changing transmitting and receiving
instruments in connection with current varying transmitters and receivers without
increase in current strength or potential over that required for operating the
current varying instruments independent of the pole changing instruments, in the
novel construction of certain of the tran-mitting instruments, in the novel means
employed for controlling the receiving instruments so that each receiving instrument
shall be operated by its corresponding transmitter only, and in the novel means
employed for preventing mutilation of the signals given by the receiving
instrumente

page_text: In the drawings accompanying this application the circuits and instruments are
shown as arranged for transmitting signals in one direction only over a line
conductor, transmitting instruments being placed at one end of the line and
receiving instruments at the other end of the line. By combining the circuits
shown in the drawings with any of the well known systems of duplex telegraphy
for transmitting signals in opposite directions over a line conductor, my system
may be adapted for transmitting signals in both directions. In the drawings the
circuits and instruments shown are adapted for sending three messages in one
direction; that is, the circuits shown, when combined with a duplex system, would
constitute a sextuplex system. My system may be used as a quadruplex system
only, by omitting one of the current varying transmitters and its corresponding
receiver. Or, if desired, by using a greater number of transmitters and receivers,
my system may be made an octuplex system, the system being capable, theoretically,
or indefinite extension, its extension being limited only by the degree of potential
allowable in the line circuit, and by the number of line relays at the receiving
station which it is practicable to use.
The objects of my invention are, first, to provide a system of telegraphy in
which two, or more than two, distinct messages may be transmitted in the same
direction over a single wire, and which may be combined with well known methods
of double transmission of messages in opposite directions, so that an equal number
of messages may be transmitted at the same time, in the opposite direction, over
the same line wire, and without confusion or mutilation of signals; second, to
provide means for so operating each receiving instrument that it may be operated
by its corresponding transmitter only and may be operated by that transmitter
whether other transmitters are operated simultaneously therewith or not; third, to
provide a system of multiplex telegraphy which may require a smaller number of
line batteries than the number of transmitters used, and consequently a smaller
potential in the line circuit for the number of messages transmitted than has been
customary with former systems; fourth, to provide ineans for operating the pole
changing transmitters and receivers without increase in the current strength or
potential over that required for the operation of the current varying instruments
independent of the pole changing instruments; fifth, to provide suitable transmitting
instruments for operating the circuits of the system, and to make these transmitting
instruments as simple as possible; sixth, to simplify the circuits and instruments
at the receiving stations which control the receiving instruments, and to so arrange
these circuits and instruments that mutilation of the signals of the receiver may be
prevented, so that each signal given may be as distinct when all the transmitters
are operating as though it were the only signal being transmitted over the line;
and seventh, to make the construction and arrangement of the circuits and
instruments of this system as simple as possible, to provide for wide ranges of
adjustment, and to render the system free from liability to derangement.
These objects are attained in the system of telegraphy herein described and
illustrated in the drawings which accompany and form a part of this application in
which the same reference letters and numerals indicate the same or corresponding
parts, and in which:
Figure 1 is a diagrammatic view illustrating the application of my system for
the transmission of three signals sinulta eusly in ne direction over a single line
wire, and Figures 2, 3, and 4 are similar views illustrating different modified
arrangements of the transmitting instruments and circuits; the modification shown
in these figures having the advantage of greater simplicity than the arrangement
of the transu itting instruments shown in Figure 1, but having a smaller range of
adjustability.
In the drawings, A is the transmitting station and B the receiving station.
T, T, and T are the transmitting instruments which, as is ordinarily the case,
are operated by electro-maguets placed in local circuits controlled by hand
keys K, K' and K" respectively. T is a pole changing transmitter and T and T"
are current varying transmitterslaving batteries and of unequal strength.

page_text: By throwing the batteries into and out of the line the transmitters are enabled to
vary the current strength of the line. Transmitter T is of ordinary construction,
battery 6 being normally to the line, and the transmitter is arranged to throw the
battery out of the line when its key K" is depressed. Transmitter T¹ is likewise
arranged to keep its battery b' to the line normally and to throw the battery out
of circuit when its key K' is depressed, but is of special construction the details of
which will be hereinafter pointed out. R, R and R are receiving instruments
of the ordinary type. L is a line conductor connecting the transmitting and receiving
Ftations. is a polar relay of ordinary construction which is placed in the line.
circuit, and which controls receiver R; 2, 3, and 4 are neutral relays of ordinary
construction, likewise placed in the line eirenit and which control receiving
instruments R and R"; relays 2, 3, and 4 are of unequal sensitivenesses, relay 4
being sufficiently sensitive to respond to the current strength of battery only,
relay 3 responding only to currents equal to or greater than the current of
battery, and relay 2 responding only to the combined strengths of batteries 6'
and 5 is a dead beat relay, having an armature mounted between the poles of
two independent magnets so that when the circuit of one magnet is completed the
armature is deflected toward the pole of that magnet and there remains after the
circuit of the magnet is broken, and until the circuit of the other in ignet is com-
pletel, when it is deflected toward the pole of that magnet. The dead beat
relay may be a polar relay having its magnets disconnected from each other
and connected with circuits in the manner shown in the drawings, but is not
necessarily a polar relay since it is not required that the armature should be
magnetized.
Transmitting instrument T resembles ordinary pale changing transmitters in that
it has a pivoted armature lever 6 provided with suitable stops and with the contact
piece 7 adapted to make contact alternately with continuity preserving contact
levers S and 81, which levers are likewise adapted to make contact with a common
stationary contact piece 9. The armature lever 6 carries a contact point 10
insulated from the remainder of the armature lever and engaging with a
continuity preserving contact lever 11 having a suitable adju-table stop.
adjustment of this stop should be such that the lever breaks contact or closes
contact, as the case may be, at the instant when the pole changing contact points
on the other end of the lever 6 reverse the polarity in the line.
The transmitter T is of ordinary construction in that it has a pivoted armature
lever 12 carrying a spring contact torgue 13 insulated from the lever 12. Engaging
with this contact tongue 13 is a pivoted armature lever 14 controlled by a
magnet 15 in a local circuit controlled by contact lever 11 and contact
point 10 of transmitter T. A pivoted contact lever 16 engages with lever 14
and has a contact point 17 insulated from that part of the lever engaging
with lever 14, which is adapted to make contact with a contact point 18.
Lever 14 carries a set screw 19, which engages with, but is insulated from, the
lever 12.
In the drawings, transmitters T, T', and T" are shown in their normal position,
keys K, K and K being open and batteries and 6" being to the line. Current
from the positive poles of battery passes through coa lucars 20 and 21,
contact tongue 22 of transmitter T, the armature lever 23 of said transmitter,
through battery and through conductors 24 and 25 to the contact lever 8 of
pole changing transmitter T ; thence through contact piece 9 and conductor 26 to
ground at G; thence through the earth to gr un connection G¹ a station B,
through conductor 27, the magnets of polar relay 1 and thence through the coils
of line neutral relays 2, 3, and 4 to line conductor L, which leads to armature
lever 6 of pole changing transmitter T at station A; thence throug the contact
lever 8', conductor 28, conductor 29, contact tongue 13 of transmitter T',
armature lever 14, contact lever 16, and
with, to the negative pole of battery .
the circuits of both batteries and
through conductor 30 connected there-
It will be seen therefore that normally
are to the line and the line circuit is

page_text: complete. If key K of pole changing transmitter T he depressed while
batteries and 6 or either of them are to the line, the transmitter is operated
and the direction of current in the line is reversed, thus operating polar relay 1 at
station B, and when key K is released transinitter T returns to normal, restoring
the current in the line to its first direction and so deflecting back to its normal
position the armature of relay 1. When key K is depressed, also, the contact
between lever 11 and contact point 10 is broken, thus deenergizing magnet 15 and
releasing armature lever 14, which is now supported by contact tongue 13 ani
set screw 19 resting upon the end of armature lever 12, since key K' is up
and armature lever 12 is therefore away from its magnet. The adjustment of
stop 19 is such that lever 14 cannot descend sufficiently far to permit lever 16
to make contact with stop 18 so long as the lever 12 is away from its magnet.
Therefore by this operation the circuit of battery is not disturbed, and it
will be seen that when key K' is up the operation of the circuit of magnet 15
and the release of armature lever 14 of said maguct has no effect upon the line
circuit.
When key K' is depressed, key K heing in normal position, contact is broken
between tongue 13 and lever 14, by the movement of lever 12. The effect of this
is to throw battery out of the line circuit, to break contact between contact
lever 14 and tongue 13, and to make contact between tongue 13 and lever 12,
causing current from battery to pass from tongue 13 through armature lever 12,
and through resistance coil R' to conductor 21 as before; that is, to cause the
current of battery 6 to pass through resistance coil R instead of through
battery b. which is now out of circuit. Resistance cuil R has the same
resistance as battery 6' and is used to keep the resistance in the line the same,
and so to preserve balance in the line. It will be seen that the operation of
transmitter T has no effect on battery 6". The throwing out of the circuit of
battery so reduces the line current, however, that the armature of line relay 2 at
station B is no longer held by its magnet, thus causing as will be seen hereafter,
the operation of receiver R.
Transmitter T as has been already stated, is an ordinary transmitter and therefore
when its key is depressed, battery " is thrown out of the line, and resistance.
coil R is thrown into the line. The throwing out of the line of battery 6" deenergizes
the magnets of relays 2 and 3 and causes their armatures to move to their back
stops; and if battery he likewise out of the line then there is no line current
and the magnet of relay 4 is likewise deenergized.
So long as either battery & or is to the line the operation of transmitter T,
by reversing the current in the line, causes the operation of polar relay 1. When
both battery and are out of the line, owing to the depression of keys K
and K, however, there is then no current in the line, and if the transmitter T is
to be operated at such an instant, some source of current must be supplied for the
line. In my former system this was done by providing a separate battery for
transmitter T, wenker thau the hatteries of the other transmitters. But since it
was necessary in this former system that the battery of one transmitter should be
of higher potential than the combined potential of the battery of the other trans-
mitter or transmitters and of the special battery of the pole changing transmitter,
when all the batteries were to the line in series the line potential became
inconveniently great. By this invention I have obviated this difficulty and have
made it possible to use batteries for the current varying transmitters of much
smaller potential than was possible in my former system, at the same time doing
away with the special battery of the pole changing transmitter. Current is supplied
to the line for operating polar relay 1, when both batteries & and & are out of the
line, by causing transmitter T, at the instant when it has reversed the line polarity,
to throw into the line circuit for but a brief instant, a battery, as b. This battery,
which need not necessarily be battery but may be so conveniently, is kept in the
line circuit for too brief a time to operate receiver R, the arrangement of
relays 2, 3, 4, and 5, as will be hereinafter explained, being such as to prevent

page_text: mutilation of signals of receiver R¹ even if the magnets of line relays shoull cause
their armatures to make a slight kick; but this brief current is of sufficient
duration to affect the extremely sensitive relay 1, and being in the opposite direction
from the current which last flowed through the line before polarity was reverse.l,
the armature of relay 1 is deflected toward the right of Figure 1. This brief
pulsation of current is obtained by means of contact points 10 and 11 of lever 6,
magnet 15, its armature lever 14, contact lever 16, and the circuits connected
therewith, in the following manner-Supposing keys K' and K" to be depressed,
batteries and are out of the line circuit, armature lever 12 of transmitter T¹
is held by its magnet to its armature and conta t is broken between contact
tongue 13 and the armature lever 14 of magnet 15. If at this instant, key K
be depressed, armature lever 6 of transmitter T is attracied towards its magnet,
contact is broken between contact point 10 and contact lever 11 and by the
operation of the circuit reversing device the polarity is reversed. The adjustment
of the stop of contact lever I is such, that contact between contact points 11
and 10 is broken at the instant of the reversal of the line p darity. The breaking
ol this contact deenergizes magnet 15, causing its armature lever 14 to fall and
make contact with contact tongue 13, contact lever 16 following the motion of
lever 14. This motion of levers 14 and 16 completes the circuit of battery ban
instaut after the reversal of the line polarity has taken place and breaks contact
between tongue 13 and lever 12 thereby throwing resistauce roil R out of the line.
But an instant after battery has been thrown into the line in this manner the
lever 16 comes in contact with its stop, so breaking contact between levers 16 and 14,
again throwing battery out of the line and throwing resistance coil R into
circuit, siuce the line circuit now runs from conductor 28, through contact points 18
and 17, lever 16 and conductor 31 to resistance coil R'. There is thus produce.l
in the line a brief current which commences an instant after the reversal of the line
polarity and exists but for a brief instant, constituting a mere pulsation. Polar
relay being extremely delicate, as is ordinarily the case, this brief current is
sufficient to operate the relay, and as the armature of the relay always stays in one
position until it is positively moved into the other position by the reversal of the
current of its magnet, this operation of the relay is sufficient to operate its
receiver R.
If while key K is depressed key K', or K", or both, are released, thus restoring
battery or to the line, the direction of the current in the line is still reversed,
and the armature of relay 1 remains against its right contact point, neutral
relays 2, 3 and 4 being operated, however, ixactly as if the direction of the current
was the normal direction. If while keys K and K are still depressed and
batteries and are out of the line, key K is released, the armature lever 6 of
transmitter T moves away from its magnet and the line polarity is again reversed,
being restored to normal condition. At the instant of this reversal of line polarity,
however, contact is made between contact lever 11 and contact point 10, thus
completing the circuit of magnet 15. The completion of this circuit causes lever t
to rise and make contact with lever 16 thus throwing battery into the line, but
this time with the normal polarity, that is, with the current from the battery
flowing in the direction to move the armature of relay 1 back to its left contact
point, Battery remains in the line only until lever 14 has broken contact with
contact tongue 13 (it being remembered that armature lever 12 is now in proximity
to its magnet). The current from battery & which passes through the line when
transmitter T returns to normal is therefore only a brief pulsation like that which
took place when key K was depressed, and is therefore too brief to operate neutral
relay 4 sufficiently to cause the operation of dead beat relay 5, although of
sufficient duration to operate polar relay 1, while it is too weak to affect relays 2
and 3, at all.
Referring now to the receiving instruments at station B, receiver R, corre-
sponding to transmitter T, is operated by a battery 40 and local circuit passing
through the armature of relay I and the right hand contact paint. Receivers R

page_text: and R are operated by a battery 41, the poles of which are connected to the
armature of relay 3 and to branching conductors 42 and 43 leading to the right
and left magnets respectively of dead heat relay 5. The front contact 44 of
relay 2 is connected by a conductor 45 to the right hand magnet of relay 5 and by
a conductor 46 to the front contact 47 of relay 4. The rear contact 48 of relay 4
is connected by a conductor 49 to the left hand magnet of deal beat relay 5 and
by a conductor 30 to the rear contact 51 of relay 2. The front c..ntact 52 of
relay 3 is connected by a conductor 53 with the armature of relay 2, and the first
rear contact 54 of relay 3 is connected by a conductor 35 with the armature of
relay 4. A second rear contact 56 of relay 3 is connected by a conductor 57
with the magnet of receiver R" and thence by a conductor 58 with the negative
pole of battery 41. It will be seen that normally a circuit is completed from
battery 41 through the front contact of relays 3 and 2 and the right hand magnet
of dead beat relay 5, thus holding the armature of relay 3 to the right. When
relay alone is deenergized the circuit of relay is broken, and the circuit
through the left-hand magnet of relay 5 is completed through conductors 50 al 49
and the rear contact of relay 2, thus moving the armature of relay 5 to the left.
If relays 2 and 3 are both deenergized, relay 4 leing still energized, the circuit
through the left hand magnet of relay 5 is broken at the front contact 52 of relay 3.
If relays 2 and 3 have been deenergized simultaneously then the front contact 52 of
elay 3 will have been broken before the rear contact 51 of relay 2 has been
completed, or in any event, before the contact 51 has been completed long enough
to move the armature of relay 5 into contact with its left hand contact point so a3
to operate receiver R', and therefore there can be no false operation of receiver R.
If relays 3 and 4 are deenergized after relay 2 has been deenergized, so that
receiver R' has already been operated at the time of the breaking of contact 52,
the armature of relay 5 is not moved and receiver R is not affected, for although
while the armatures of relays 3 and 4 are moving there is no current flowing
through either magnet of relay 5, the armature of this relay will not move, and as
soun as contact 49 and 48 is completed current again flows through the left hand
magnet of relay 5.
If relay 4 be deenergized simultaneously with relays 2 and 3, or if it be
deenergized after relays 2 and 3 have been deenergized simultaneously (under
which circunstance as above stated, the armature of relay 5 would remain in
contact with its right contact point) the circuit through the left hand magnet of
relay 5 is completed through conductor 49, contact 48 of relay 4, conductor 55 and
rear contact 54 of relay 3, thus operating relay 5 and receiver R. Receiver R' is
operated by a local circuit and battery controlled by relay 5.
When relay 3 is deenergized a cirenit is completed from battery 41 through its
second rear contact 56, conductors 57 and 58 and the magnet of receiver R', thus
operating said receiver.
Relay 5 may serve as a receiver without any special receiver R', and relay 3
might serve as a receiver without any special receiver R. But it is considered
preferable to employ these special receiving instruments, both because special
receivers are more easy to read from, and because it is probable that from time to
time there will be slight false movements of the armatures of relays 3 and 5, not
sufficient to cause operation of the special receivers R' and R", but still sufficient
to cause confusing clicks of relays 3 and 5, were they used as receivers.
The operation of the circuits of my system of telegraphy is as follows: The
receiving and transmitting instruments being in positions shown in Figure 1, and
batteries and being to the line, if key K be depressed and transmitter T
operated the line polarity will be reversed, thus deflecting the armature of relay 1
to the right, completing the local circuit of battery 40 and causing the operation
of receiver R; neutral relays 2, 3, and 4 being unaffected by this reversal of
polarity, since the current in the line is practically constant in strength. At the
instant of the reversal of polarity a slight false movement of the armatures of
neutral relays may take place, but such false movement may be corrected by the use of

page_text: a condenser. In any case this false movement is not sufficient to conplete a circuit
through receiver R or through the left land magnet of relay 5. When the key
is released transmitter T returns to normal, restoring the line current to its normal
polarity and deflecting the armature of relay 1 to normal, thus breaking the
circuit of battery 40 and restoring receiver R to normal.
When key Kis depressed, transmitter T being at normal position, transmitter T'
is operated and since contact lever 14 is held upward by magnet 15, contact is
broken hetween lever 14 and tongue 13 and at the same instant is completed
between tongue 13 and armature lever 12, thus throwing battery bout of the
line, and throwing the corresponding resistance coil R' into the line, so that the
line circuit is not .broken and the line resistance remains constant. Throwing
battery 6' out of the line, however, so reduces the line potential that relay 2 is
deenergized, and rear contact 51 is closed, thus completing a circuit through the
left hand magnet of relay 5, deflerting the armature of the relay to the left and
operating receiver R. When key K is released contact is broken between
tongue 13 and lever 12 and is minde between tongue 13 and lever 14, thus restoring
battery to the line, throwing resistance R out of the line, and reenergizing
relay 2, thus breaking the circuit through the left hand magnet of relay 5,
completing the circuit of the right hand magnet of the relay and operating
receiver R
When key K is depressed battery is thrown out of the line and re-istance K"
is thrown into the line, the line potential being so reduced thereby that relays 2
and 3 are deenergized and the circuit through the armature of relay 2 is broken
at the front contact of relay 3, so that receiver R' is not affected by the operation
of relays 2 and 3 and the circuit through receiver R" is completed, operating the
receiver. When key K" is released battery is returned to the line, relays 2
and 3 are again energized and receiver Ris returned to normal. If, while
key K" is depressed, key K' is also depressed, relay 4 is deenergized and contact 48
is closed, completing a circuit through the left hand magiet of relay 5 and
operating receiver R.
If while keys K' and K" are depressed, so that there is no current in the line,
key K is depressed so as to operate transmitter T, the line polarity is reversed and
at the instant of reversal the circuit of magnet 15 is broken, permitting contact
lever 14 to drop and make contact with tongue 13 of transmitter T', thus throwing
battery into circuit and throwing resistance R' out of circuit. An instant after
contact is made, contact lever 16 comes in contact with its stop 18 and breaks
contact with the lever 14, thus again throwing battery out of circuit and
throwing resistance I into circuit. The Lriet pulsation of current thus produced
in the line and in the direction opposite to the normal polarity of the line is
not sufficient to cause the operation of receiver K' but is sufficient to deflect the
armate of the delicate polar relay 1 to the right, thus operating receiver R. If
keys K and K", or either of them, be released before key K is released, so as to
place one of the transmitting batteries in the line, reversal of line polarity which
takes place when key K is released deflects the armature of relay 1 back to its
forn.er position, in the ordinary manner. But if keys K' aud K" are still
depressed when key K is released, at the instant when the reversal of line polarity
takes place magnet 15 is energized and raises its armature lever 14, which lever
nakes contact with lever 16, thus completing the cir. uit of battery ', and an
instant afterward breaks contact with tongue 13, thus throwing battery again
out of circuit. The pulsation of current thus produced, which is as brief as
that produced when key K was depressed, and which takes place an instant after
the normal polarity has been restored, deflects the armature of relay 1 to the left,
thus breaking the circuit of battery 40 and restoring receiver R to normal
polarity.
The use of the dead leat relay 5 to control the receiver R', instead of a simple
repeating relay, prevents any possible mutilation of the signals of said receiver.
In no case is receiver R" subject to mutilation, Lecause its circuit is contro.led by

page_text: relay 3 only. But the circuits of relay 5 are controlled by all three line relays
and it is inevitable with the arrangement of contact points and circuits adopted
that during a portion of the time while these relays are operating there shall be
no current passing through the magnets of relay 5. The fact, however, that the
mere breaking of the circuits of the magnets of relay 5 does not cause movement
of the armature of the relay, prevents false operation of the circuit of receiver R',
and so prevents mutilation of the signals. The dead heat relay likewise acts to
prevent possible disturbance of the siguals of receiver R¹ when battery is thrown
into the line momentarily to operate relay 1. In no case can relay 3 be operated
by such throwing of battery into the line, since the battery is not strong enough
to affect it. But relay 2 or 4 may be momentarily affected thus causing a slight
movement of their respective armatures away from their front contact points, breaking
the circuit through the left hand magnet of relay 5. But before relay 2 or 4 can
close a circuit through the right hand magnet of relay 5, battery & will have been
again cut out of circuit, so that no disturbance of receiver R can follow,
In Figures 2, 3, and 4, are shown modified forms of transmitting instruments for
producing the pulsatory current required for the operation of the polar relay 1.
In Figure 2 an ordinary pole changing mechanism is substituted for the contact
point 10 and contact lever 11 of the transmitter T of Figure 1, and the contact
lever 16 of transmitter T of Figure 1 is dispensed with. When key K is
depressed, after keys K and K have been depressed, transmitter T is operated,
thus reversing the line polarity and at the same instant reversing the current
which flows through magnet 15 of transmitter T. The relationship between
maguet 15 and its armature lever 14 is extremely delicate, so that the slight
interruption of current at the instant of reversal may be sufficient to cause the
armature lever 14 to drop temporarily and so to make contact with tongue 13, thus
throwing battery into the line, and to break contact between tongue 13 and
armature lever 12, thus throwing resistance R' out of the line. The almost instant
reattraction of lever 14 throws battery out of the line and throws resistance R
into the line. But in this brief instant of contact a pulsation of current has passed
over the line sufficient to operate the polar relay 1.
In Figure 3 a somewhat similar arrangement is shown. In this case the
armature lever 6 when attracted to its magnet is caused to break contact with a
lever 60 and an instant thereafter to make contact with a second lever 61. Both
of these levers are connected to the circuit of magnet 15, as is the armature
lever 6. The breaking of contact between levers 6 and 60 causes lever 14 of
magnet 15 to drop, making contact with tongue 13 and breaking contact between
tongue 13 and lever 12. An instant after, lever 6 makes contact with lever 61 and
raises lever 14. A similar brief interruption of the circuit of magnet 15 takes
place when key K is released.
In Figure 4 is shown a still different arrangement of the parts of the transmitting
instruments. It is obvious that since the pulsatory currents which operate the
polar relay 1 are too brief to operate the neutral relays controlling receiver R
that these currents in the line may be continuous without affecting the operation of
the neutral relays. In Figure 4 there is provided an automatic vibrator and
circuit interrupter such as is used ou induction coils, and which is arranged to
continuously make and break the circuit of battery when the armature lever 12
of transmitter T is in proximity to its magnet. So long as key K' is up, the
operation of this vibrator has not effect, since armature lever 14 is held up by
stopserew 19 being in contact with lever 12. But when key K' is depressed and
the armature lever 12 is in proximity to its magnet the action of the vibrator is to
throw battery into the line continuously but for brief and rapidly recurring
instants. The vibrator may be of any usual construction. In the form shown a
magnet 15 is arranged to vibrate a lever 14' and the circuit of a local battery 65
passes through the armature 14' and through a spring tongue 66, adapted to make
contact with a lever 14. With this construction, when the circuit of battery 65
is completed through contact point 66 and lever 14', magnet 15 is energized

page_text: and draws lever 14' away from contact point 66, thus deenergizing magnet 15¹.
A retractile spring 67 then draws lever 14 back into contact with tongue 66.
As shown in Figure 4, the contact lever 16, shown also in Figure 1, is used
to operate with the tongue 13 and lever 14. But instead of this the current from
battery may be passed through the lever 14' in the manner shown in Figures 2
and 3.
The operation of the circuits and instruments of Figure 4 is as follows: Keys K'
and K" being first depressed, when key K is depressed transmitter T operite and
reverses the polarity in the line. At the next succeeding vibration of lever 14',
which causes battery to be put to the line for a brief instant, the armature of
relay at station B is deflected to the right. Succeeding pulsations of current
bave no effect on relay 1 wbile key K is depressed. But when key K is released,
the line polarity is restored to normal and the first pulsation of current following
such restoration deflects the armature of relay 1 to the left again. The arrange-
ment shown in Figure 4 has this advantage, that while the continuous pulsatory
current does not tend to change the position of the armature of polar relay 1
except immediately after the operation of the transmitter T, it does operate to
hold the armature of relay 1 and prevent any false noveinents thereo"." Where
several line conductors are in close proximity it might happen that a current
induced in conductor L. from another conductor in close proximity thereto would
cause a false movement of the armature of relay 1. The continuous pulsatory
current, however, holds the armature in the position corresponding to the position
of transmitter T.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what i
claim is
1. In a system of multiple telegraphy, the combination, with a line conductor,
meaus for supplying current to the line, a current varying transmitter adapted to
vary the current strength in the line and a receiving instrument corresponding to
said transinitting instrument and operated by variations in the line current produced
thereby, of a pole changing transmitter arranged when operated to change the line
polarity, a receiving instrument corresponding thereto and operated by reversal of
the line polarity, and a pulsatory current producing device, arranged to produce in
the line current pulsations of too brief duration to affect the receiver corresponding
to said current varying transmitter, whereby the receiver corresponding to said
pole changing transmitter may be operated independently of the operation of the
current varying transmitter, substantially as described.
2. In a system of multiple telegraphy, the combination, with a line conductor,
means for supplying current to the line, a current varying transmitter adapted to
vary the current strength in the line, and a receiving instrument corresponding to
said transmitting instrument and operated by variations in the line current produced
thereby, of a pole changing transmitter arranged when operated to change the line
polarity, a receiving instrument corresponding thereto and operated by reversal of
the line polarity, a magnet operated by a circuit controlled by said pole changing
transmitter, contact points controlled by said magnet, connected with a means for
varying the line current, and arranged when said magnet is operated by said pole
changing transmitter to vary for a brief instant the line current, whereby a current
pulsation is produced in the line and the receiver corresponding to said pole
changing transmitter may be operated independently of the operation of said
current varying transmitter, substantially as described.
3. In a system of multiple telegraphy, the combination, with a line conductor,
means for supplying current to the line, a current varying transmitter adapted to
vary the current strength in the liue, and a receiving instrument corresponding to
said transmitting instrument and operated by variations in the line current produce
thereby, of a pole changing transmitter arranged when operated to change the
line polarity, a receiving insti un.eut corresponding thereto and operad by
B

page_text: reversal of the line polarity, a magnet operated by a circuit controlled by said pole
changing transmitter, contact points controlled by said magnet and arranged to
throw into the line for a brief instant, when operated, a source of current, whereby
a current pulsation may he produced in the line and the receiver corresponding to
said pole changing transmitter may be operated independently of the operation of
said current varying transmitter, substantially as described.
4. In a telegraphic transmitter, the combination, with a contact lever and a
contact piece carried thereby and insulated therefrom hut arranged to make
contact therewith, said contact lever anl contart piece being arranged to be
connected to a line conductor, of a second contact lever arranged to make contact
with said contact piece and to break contact between said contact piece and first
contact lever, adapted to follow the movement of said contact piece when said
first contact lever moves, and arranged to be connected to a source of electric
energy for the line, means for moving said first contact lever and contact piece
away from said second contact lever, and a magnet arranged when energized to
prevent said second contact lever from following said contact piece, substantially
as described.
5. In a telegraphic transmitter, the combination, with a contact lever and a contact
piece carried thereby and insulated therefrom bat arranged to make contact there-
with, said contact lever and contact piece being arranged to be connected to a
line conductor, of a second contact lever arranged to make contact with said
contact piece and to break contact between said contact piece and first contact
lever, adapted to follow the movement of said contact piece when said first contact
lever moves, and arranged to be connected to a source of electric energy for the
line, means for moving said first contact lever and contact piece away from said
contact lever, a magnet arranged when energized to prevent said second contact
lever from following said contact piece, means for breaking the connection between
said second contact lever and said source of electric energy, and means for
completing the line circuit around said contact levers and contact piece when the
connection between said second contact lever and said source of electric energy is
broken, substantially as described.
6. In a telegraphic transmitter, the combination, with a contact lever and a
contact piece carried thereby and insulated therefrom but arranged to make
contact therewith, said contact lever and contact piece being arrangel to be
connected to a line conductor, of a second contact lever arranged to make contact
with said contact piece and to break contact between said contact piece and first
contact lever, and to follow the movement of said contact piece when said first
contact lever moves, a third contact lever arranged to be connected to a source of
electric energy for the line and to make contact with said second contact lever,
means for moving said first contact lever and contact piece away from said second
contact lever, a magnet arranged when energized to prevent said second contact
lever from following said contact piece, means for breaking contact between said
second and third contact levers when said second lever follows said contact piece,
and contact points operated by said third contact lever and arranged to complete
the line circuit around said first and second contact levers and contact piece when
contact is broken hetween said second and third contact levers, substantially as
described.
7. In a system of multiple telegraphy, the combination, with a line conductor,
means for supplying current to the line, and two transmitting instruments each
adapted when operated to vary the current strength of the line to a degree
different from that by which the other transmitter varies the strength of said line
current, of three line relays of different sensitivenesses, arranged to be operated
respectively by the current strength produced when the first transmitter is
operated, when the second transmitter is operated, and when both transmitters are
operated together, a dead heat relay, circuits for operating said dead beat relay
controlled by said first and by said third line relays, each relay being arranged to
cause the arn.ature of said dead beat relay to be deflected to the one side or the

page_text: other accordingly as the armature of the line relay is in proximity to its magnet
or away therefrom, the circuits of said first line relay being arranged to be
broken by said second line relay when the latter is operated, a receiving device
operated by said dead beat relay, and a receiving device operated by said second
line relay, substantially as described.
8. In a system of multiple telegraphy, the combination, with a line conductor,.
means for supplying current to the line, and two transmitting instruments adapted
each when operated to vary the current strength of the line to a degree different
from that by which the other transmitter varies the strength of said line current,
of three line relays of different sensitivenesses, arranged to be operated respectively
by the current strengths produced when the first transmitter is operated, when
the second transmitter is operated, and when both transmitters are operated
together, a dead beat relay, circuits for operating said dead beat relay controlled
by said first and by said third line relays, each relay heing arranged to cause the
armature of said dead beat relay to be deflected to the one side or to the other
according as the armature of the line relay is in proximity to its magnet or away
therefrom, and the circuits of the first line relay being broken and of the third
line relay being closed by the second line relay, a receiving device operated by
said dead beat relay, and a receiving device operated by said second line relay,.
substantially as described.
Dated this 28th day of January 1896.
MARKS & CLERK,
18, Southampton Buildings, London, W.C., and
13, Temple Street, Birmingham, Agents.