IMPROVEMENTS IN TELEGRAPHIC Appa- RATUS
Year: 1875

page_text: LETTERS PATENT to Martin Benson, of No. 9, Southampton Buildings,
London, for the Invention of “IMPROVEMENTS IN TELEGRAPHIC Appa-
RATUS." A communication from abroad by Joseph Olmsted, of the
City and County of Providence, in the State of Rhode Island,
United States of America.
PROVISIONAL SPECIFICATION left by the said Martin Benson at the
Office of the Commissioners of Patents, with his Petition, on the
24th December 1875.
I, MARTIN BENSON, of No. 9, Southampton Buildings, London, do
hereby declare the nature of the said Invention for "IMPROVEMENTS IN
TELEGRAPHIC APPARATUS," a communication to me from abroad by Joseph
Olmsted, of the City and County of Providence, in the State of Rhode
Island, United States of America, to be as follows:-
I seek by my Invention the simultaneous transmission on a single
'

page_text: me necessarily involves a capacity for transmitting two signals at the
same time on the same wire, whether one signal be transmitted from
each end or both be transmitted from the same end of the wire.
It has heretofore been proposed by means of so-called qaudruplex
telegraphic apparatus to simultaneously transmit two signals or
messages over the same wire in the same direction, by employing the
positive and negative currents alternately. Also it has heretofore been
proposed to send two signals or messages simultaneously from opposite
ends of a line, by employing both the positive and negative currents
alternately. By means of my Invention I am enabled to accomplish
these results by employing a battery current, which is applied to the
line in the usual manner, and without alteration of current as heretofore
proposed.
For accomplishing my purpose I employ the following well known
means. The line wire, two main batteries, two ground connections,
four finger keys, four sounders, several resistance coils or rheostats, two
transmitters of ordinary construction performing their proper functions,
two "cut outs" or "shunts," which resemble transmitters of ordinary
construction for performing an automatic controlling influence over the
electric current, six relay magnets, and several local batteries.
In addition to the above I employ two transmitters each having an
armature lever of novel construction, in that it is composed of two
plates or bars insulated from each other, and so arranged that each bar
may communicate with one of the two usual contact points or stops.
These transmitters perform usual functions, and also serve as inter-
mediate circuits for avoiding a resistance coil when occasion requires
full force of the current.
With the means described by reason of their novel combination and
arrangement with relation to each other and a novel system of electric
connections, I am enabled practically to attain the object sought as
previously indicated. The line wire, main batteries, and ground con-
nections are arranged as heretofore. The finger keys have local
batteries which are connected thereto and with the transmitters, and the
sounders have also local batteries connected with them in the usual
manner, but the sounders are connected with their relays in a novel
manner. Adjacent to each ground connection is a resistance coil as
heretofore employed for balancing the resistance of the line.

page_text: I employ in connection with each of the transmitters at each end of
the line a resistance coil, so arranged that either or both of the coils
may be automatically brought into service when required. The relay
magnets are located as is usual in duplex telegraphic systems with
relation to the main line, the sounders and transmitters, and as here-
tofore the outgoing current passes through both coils of each relay
magnet at the transmitting end of the line. Each end of the line is
provided with three relay magnets. Their armatures are variably.
weighted. Two of the magnets, one at each end, have their armatures so
set that with a small portion of the electric current applied to them,
their armature levers will be held to the front stops, and when this
current is lessened the armature levers move to the back stops and make
connection with their respective sounders. At each end of the line is
one of two other relay magnets each of which communicates with a
sounder. The normal or usual position of their armature levers is
against the front stops, and they are so weighted that they will remain
against said stops until the holding force of the magnets is reduced to
about one half of their normal power, at which time their armature
levers fall to the back stops and make connection with their respective
sounders. Between these two relay magnets at each end of the line I
employ still another relay magnet, which is electrically connected by
conductors to each of its neighbouring relays. It may have no sounders
of its own, but can be arranged to affect or controll the sounder of the
relay magnet first described, by co-operating with or through said relay
under circumstances hereafter recited, or it may be arranged to
communicate directly with that sounder without co-operating with or
through the relay last referred to.
My Invention involves a novel method of transmitting two signals at
the same time over the same line of wire from each end and in each
direction, which consists in placing the battery current under the
control of four finger, keys without changing the relations between the
poles of the batteries and the line wire, so that it may be wholly cut off
from the line under one condition, or reduced say to two-thirds of its
power under another condition, and to say one-third of its power under
another condition, or employed in its full force under still other
conditions.
My Invention consists mainly in the combination with four keys, four
sounders. a line wire suitable main and local batteries and suitable
.

page_text: intermediate conductors of means for directing the battery force or
power to the main line in three unequal powers, means for wholly
neutralizing said power, and of means for placing each sounder into
communication with its key, whereby with unchanged relations
between the poles of the main batteries and the line wire, messages or
signals may be transmitted from two of the keys at the same time, over
the same wire and in the same direction while signals are being
received from both of the other keys as set forth.
My Invention also consists partially in the combination with the line
wire and its batteries of two keys and their local batteries, two trans-
mitters controlled by the keys and their batteries, two rheostats or
equivalent means for graduating the power of the battery current to
line controlled by the transmitters, a cut out or shunt all at one end of
the, line, and at the other end of the line three relay magnets with
armatures variously weighted, and two sounders with local batteries
controlled by said relay magnets.
It further consists in the combination of two keys and their local
batteries with a transmitter capable of performing usual service, a
transmitter having an armature lever composed of insulated bars or
plates, two rheostats, and a system of connecting conductors, whereby a
desired portion of the battery current may be witheld or the current cut
off entirely.
It further consists in the combination with a ground wire and its
rheostat of an automatic shunt or "cut out" composed of an electro-
magnet, an armature, and the usual front and back stops, a battery wire
which charges the magnet, a conductor which connects the front stops
and armature with the ground wire on each side of its rheostat, and a
means for cutting off the current from the battery to the magnet of the
"cut out."
It further consists in the combination with a sounder and its local
battery of two relay magnets having their armatures set at different
resistances, and arranged to separately operate the sounder when_call is
made thereon from its proper terminating key.
It further consists in the combination of a sounder having a local
battery and a relay magnet, which normally holds its armature lever to
the front stop with but little electro-magnetic force, and permits the
sound to operate when its armature lever is on its back stop with a

page_text: second relay magnet, which is connected to the first, holds its own
armature lever to its front stop by a greater force, is located between
the first relay and the line wire which charges the magnets of both
relays, and is arranged to shunt the current received by. it to a ground
wire, and so protect the weaker magnet in the performance of its duty
from a current which would prevent it from causing its sounder to
respond to its proper key.
And still further my Invention consists à transmitter of the com-
bination with an eléctro-magnet of an armature lever composed of two
separate bars or plates insulated from each other, and arranged so that a
surface of one plate will communicate with the front stop, and a surface
of the other plate or bar will communicate with the back stop, whereby
each bar or plate may serve as a conductor independently of the other.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Martin Benson in the Great Seal Patent Office on
the 10th June 1876.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, MARTIN
BENSON, of No. 9, Southampton Buildings, London, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-fourth day of December, in the
year of our Lord One thousand eight hundred and seventy-five, in the
thirty-eighth year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said Martin Benson, Her special
licence that I, the said Martin Benson, my executors, administrators,
and assigns, or such others as I, the said Martin Benson, 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
TELEGRAPHIC APParatus,” a communication to me from abroad by Joseph
Olmsted, of the City and County of Providence, State of Rhode
Island, United States of America, upon the condition (amongst others)
that I, the said Martin Benson, my executors or administrators, by an

page_text: instrument in writing under my, or their, or one of their hands and
seals, should particularly describe and ascertain 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 Martin Benson, do hereby declare
the nature of my said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the
following statement :-
I seek by my Invention the simultaneous transmission on a single
wire of four signals, two in each direction. This requirement as met by
me necessarily involves a capacity for transmitting two signals at the
same time on the same wire, whether one signal be transmited
from each end, or both be transmitted from the same end of the
wire.
It has heretofore been proposed by means of so-called quadruplex
telegraphic apparatus to simultaneously transmit two signals or
messages over the same wire in the same direction by employing the
positive and negative currents alternately. Also it has been heretofore
proposed to send two signals or messages simultaneously from opposite
ends of a line by employing both the positive and negative currents
alternately. By means of my Invention I am eabled to accomplish
these results by employing a battery current, which is applied to the
line in the usual manner and without alteration of current, as heretofore
proposed.
-
For accomplishing my purpose I employ the following well-known
means: The line wire, two main batteries, two ground connections,
four finger keys, four sounders, several resistance coils or rheostats, two
transmitters of ordinary construction performing their proper functions,
two "cut-outs" or "shunts," which resemble transmitters of ordinary
construction for performing an automatic controlling influence over the
electric current, six relay magnets, and several local batteries.
In addition to the above I employ two transmitters, each having an
armature lever of novel construction, in that it is composed of two
plates or bars insulated from each other, and so arranged that each bar
may communicate with one of the two usual contact points or stops.

page_text: These transmitters perform usual functions, and also serve as inter-
mediate circuits for avoiding a resistance coil when occasion requires
full forc of the current.
With the mean described, by reason of their novel combination and
arrangement with relation to each other, and a novel system of electric
connections, I am enabled to practically attain the object sought, as
previously indicated. The line wire, main batteries, and ground con-
nections are arranged as heretofore. The finger keys have local
batteries which are connected thereto, and with the transmitters, and
the sounders have also local batteries connected with them in the usual
manner, but the sounders are connected with their relays in a novel
manner. Adjacent to each ground connection is a resistance coil, as.
heretofore employed, for balancing the resistance of the line.
I employ in connection with each of the transmitters at each end of
the line a resistance coil so arranged that either or both of the coils
may be automatically brought into service when required. The relay
magnets are located as is usual in duplex telegraphic systems, with
relation to the main line, the sounders and transmitters, and, as hereto-
fore, the outgoing current passes through both coils of each relay
magnet at the transmitting end of the line. Each end of the line is
provided with three relay magnets. Their armatures are variabely
weighted. Two of the magnets, one at each end, have their armatures
so set that with a small portion of the electric current applied to them,
their armature levers will be held to the front stops, and when this
current is lessened, the armature levers move to the back stops and make
connections with their respective sounders. At each end of the line is
one of two other relay magnets, each of which communicates with a
sounder. The normal or usual position of their armature levers is
against the front stops, and they are so weighted that they will remain
against said stops until the holding force of the magnets is reduced to
about one-half of their normal power, at which time their armature
levers fall to the back stops and make connection with their respective
:sounders. Between these two relay magnets at each end of the line I
employ still another relay magnet which is electrically connected by
conductors toe ach of its neighbouring relays. It may have no sounder of
its own, but can be arranged to affect or control the sounder of the relay
magnet first described by co-opperating with or through said relay under
circumstances hereafter-recited, or it may be arranged to communicate
:
: j

page_text: directly with that sounder without co-opperating with or through the
relay last refered to.
My Invention involves a novel method of transmitting two signals at
the same time over the same line wire from each end, and in each
direction, which consists in placing the battery current under the
control of four finger keys without changing the relations between the
poles of the batteries and the line wire, so that it may be wholly cut off
from the line under one condition or reduced to, say, two-thirds of its
power under another condition, and to, say, one-third of its power under
another condition, or employed in its full force under still other
conditions.
My Invention consists mainly in the combination with four keys, four
sounders, a line wire, suitable main and local batteries, and suitable
intermediate conductors, of means for directing the battery force or
power to the main line in three unequal powers; means for wholly
neutralizing said power, and of means for placing each sounder into
communication with the keys, whereby with unchanged relations between
the poles of the main batteries and the line wire messages or signals
may be transmitted from two of the keys at the same time over the
same wire and in the same direction, while signals are being received
from both of the other keys, as set forth.
My Invention also consists partially in the combination with the line
wire and its batteries, of two keys and their local batteries, two trans-
mitters, controlled by the keys and their batteries, two rhostats or
equivalent means for graduating the power of the battery current to
line, controlled by the transmitters, a cut out or shunt, all at one
end of the line; and at the other end of the line three relay magnets
with armatures variously weighted, and two sounders with local batteries
controlled by said relay magnets.
'
It further consists in the combination of two keys and their local
batteries with a transmitter capable of performing usual service, a
transmitter having an armature lever composed of insulated bars or plates,
two rheostats, and a system of connecting conductors, whereby a
desired portion of the battery current may be witheld, or the current
cut off entirely.
It further consists in the combination with a ground wire and its
rheostats, of an automatic shunt or "cut out," composed of an electro-

page_text: magnet, an armature, and the usual back and front stops; a battery
wire which charges the magnet, a conductor which connects the front
stop and armature with the ground wire on each side of its rheostat,
and a means for cutting off the current from the battery to the magnet
of the cut out.
It further consists in the combination with a sounder and its local
battery of two relay magnets having their armature set at different
resistances and arranged to separately operate the sounder when call is
made thereon from its proper transmitting key.
It further consists in the combination of a sounder having a local
battery and a relay magnet which normally holds its armature lever to
the front stop with but little electro-magnetic force, and permits the
sounder to operate when its armature lever is on its back stop, with a
second relay magnet which is connected to the first, holds its own
armature lever to its front stop by a greater force, is located between the
first relay and the line wire which charges the magnets of both relays,
and is arranged to shunt the current received by it to a ground wire,
and so protect the weaker magnet in the performance of its duty from
a current which would prevent it from causing its sounder to respond to
its proper key.
And still further, my Invention consists in a transmitter, of the com-
bination with an electro-magnet, of an armature lever composed of two
separate bars or plates insulated from each other, and arranged so that
a surface of one plate will communicate with the front stop, and a
surface of the other plate or bar will communicate with the back stop,
whereby each bar or plate may serve as a conductor independently of
the other.
In order to fully describe my Invention I will refer to the accom-
panying Drawings, in which Fig. 1 illustrates a complete apparatus at
the home station, and Fig. 2 a similar apparatus at the foreign station.
Fig. 3 illustrates a single apparatus, whereby two signals may be sent
simultaneously over the same line in the same direction.
It will be seen that Fig. 3 is a counterpart of one-half of each appa-
ratus, shown at each end of the wire in Figs. 1 and 2, and the several
3 parts of the apparatus are lettered in those Figs.

page_text: Figs. 5 and 6 illustrate different modes of battery arrangement. The
main line wire between the two stations is indicated at V.
A and B denote the finger keys at the home station, Fig. 1, and C
and D the keys at the foreign station, Figs. 2 and 3. The sounders of
the home station are shown at E and F, and at G and H at the foreign
station. Each finger key and sounder is provided with a local battery
as at u. The finger key are in each instance connected with the
magnets of their respective transmitters, which are shown at I and J
in the home station, and K and L in the foreign station. Their con-
necting conductors are shown in dotted lines in each instance, and they :
are arranged in the usual manner.
The sounders are also connected with their respective relay magnets
by conductors indicated by dotted lines as follows:-Home sounder E
to relay O; sounder F to relay Q; and at the foreign station sounder G
may be connected in like manner, as shown in Fig. 1 to relay R; or :
by a different mode of connection hereafter fully described. Sounder H
however is connected with its relay T in the same manner as shown at
the home station.
The relay magnets at the home station have their counterparts at the
foreign station. The main batteries are plainly designated in the 2
Drawings, and the ground connections are shown at Z.
For the purpose of illustration it will be assumed that 150 represents the
full power of the main battery, and it is to be understood that the three
relay magnets at each end of the line have armatures which are variably
weighted but that they correspond in this respect with the relays at the a
other station as follows:-Relay O with R, P with S, and Q with T.
The armatures of relays marked 150 are attracted by that power, those
of relays marked 50 are released at that or a lesser power; those of
relays marked zero (0) are released when their magnets are powerless.
I will first describe the normal condition of the line when at rest.
Although the full force of the battery is represented by 150 the normal
condition of the entire apparatus is 100, at which time the armature
lever of the transmitters I, J, and K, L, are of course on their back
stops (their magnets not being then affected by the finger key local
batteries). The armature levers of the "cut outs" or shunts M. and N,
and the relays O, Q, R, and T, are all against their front stops. The
armatures of relays O and R are so set that when the power of the

page_text: battery is reduced to zero they will be released from their front stops,
while the armatures of relays Q and T are so set that they will be
released from their front stops when the battery force is not greater
than 50. The armatures of the relays P and S are so weighted that
they remain on their back stops unless the power of their magnets are
augmented to a force nearly or quite equal to 150, or the full force of
the battery, which is when the line is at rest modified to 100, as
stated.
This modification of the power of the battery is effected as follows in
connection with Fig. 1:-The current from the main battery at the
home station for instance, by way of the wire indicated in solid lines at
b, on reaching the transmitter at I, finds a fork or branch in its
conductor; one of these branches is obstructed by the resistance coil
shown at No. 1, and therefore the current passes along the armaturé a
of the transmitter I through its back stop, thence by another wire
indicated in solid lines and by arrows No. 1 and 2, and through the
resistance coil No. 2, which partially neutralizes the power of the
current to the extent of one-third of its full capacity, leaving a force,
which as before stated, may be represented by 100. At the foreign
station the same arrangement of conductors and resistance coils is
shown. The main battery current reaches the main line V by passing
through the magnet of the cut out or shunt M at the home station, and
through each core of each magnet of the relays O, P, and Q, and at the
foreign station by passing through magnets of cut outs N and relays
R, S, T, as is clearly shown in each case by conductors indicated in
solid lines.
For explaining the working of the apparatus I will first describe how
a single message may be sent over the line from the foreign to the home
station. As before stated Fig. 3 illustrates a single apparatus, and its
parts are designated by the same letters employed in Figs. 1 and 2. In
said Fig. 3 the transmitting devices are as in Fig. 2, and the receiving
devices as in Fig. 1, and therefore either of the Drawings may be
refered to in connection with the descriptive matter relating to the.
transmisson of signals from the foreign to the home station. The
finger key at C is depressed, which permits its local battery u to
charge the magnet of transmitter K which attracts the armature a to
the front stop. The current from the main battery having now no
conductor except the wire shown in solid lines passes in direction of

page_text: arrow No. 3, to resistance coil or rheostat No. 3, whereby the force of
the current is reduced from 100 to 50; beyond this point it continues on
the wire b to transmitter L, as next described. This transmitter L has
an armature lever a' of novel construction, illustrated more fully in
Fig. 4. It is composed of two bars or plates, which are insulated from
each other. One bar, as at x, constitutes the front surface of the
armature lever for contact with the front stop; the other bar, as at y,
constitutes the rear surface for contact with the rear stop.
The current from the rheostat No. 3 (thereby reduced to 50) passes
to the upper portion of the armature lever a¹, thence to the back stop,
thence by wire, as per arrow No. 2, to the rheostat No. 4, thence to and
through the magnet of shunt or cut out N, as indicated by arrow 5, to a
point where the conductor is divided into two parts, each part connect-
ing with one of the coils of the magnet of relay R passing through said
coils, and thence through the coils of magnets in relays S and T in like
manner. One portion of the current, after passing relay T, passes to
the ground wire as per arrow 6, and the other portion to the line wire V,
as per arrow No. 7. As is well known the divided current in thus
passing through each coil fails to effect the magnets in any manner.
It will be remembered that the armature lever of relay Q is against its
front stop, and it is here to be noted that the release of this armature
and its contact with its back stop permits the sounder F to be operated
by its local battery. The armature lever of relay Q is held to the front
stop by a force greater than 50, and as the power of the current from
key C is but 50 the armature is therefore released and the sounder F
operated. Leaving the key C down and the sounder F executing its
signal, I will next describe how at the same time signals may be
transmitted from the key D to the sounder E at the home station. The
key D being depressed (the magnet of transmitter L is charged, and
its armature lever a¹ carried to its front stop. The battery current being
already reduced to 50 is still further reduced to zero by cutting off the
current entirely from its battery at the back stop of the transmitter L,
and therefore the armature of relay O is released from its front stop, and
by contact with its back stop permits the sounder E to be operated by
its local battery.

page_text: control its sounder after key C has ceased control of sounder F..
Pressure being removed from key C the magnet of transmitter K
releases its armature, which returns to its back stop; the battery
current then instead of passing through rheostat 3 passes along.
armature lever a of transmitter K through its back stop along the
conductor to the back stop of transmitter L, thence towards the
rheostat 4, but finding resistance there it takes the easier conductor as
indicated by arrow No. 8, backward and downward to the under plate
of the armature lever a¹ of transmitter L, thence as before to the main
wire with the full force of the battery, i.e. 150. On reaching the
relay P at the home station the entire current is shunted thereby to the
ground wire, leaving the relay O still under the control of the key D. The
full battery current approaches the relay P as indicated by arrow No. 9,
and is shunted by passing through the adjacent coil of the magnet, and
from thence as per arrow No. 10 by wire (in dotted lines) back to the
front stop of the relay, thence along its armature lever to its base, thence
by the wire (in dotted lines) to opposite end of the other coil, as per
arrow, No. 11, back through the coil to its front end, thence to the
ground wire as per arrows 12 and 13.
It will be seen that the outgoing current from the home station in no
manner affects the home relays and sounders, because the current is
equally divided and passes through each coil of each magnet in the same
direction, one division of the current ultimately reaching the line wire,,
and the other portion the ground wire.
Signals from keys A and B at the home station will be transmitted to
the sounders at the foreign station in the same manner as has been
described in connection with signals from the opposite direction. The
local battery connections between relay O and its sounder E, at the
home station are shown to be somewhat unlike the connection between
the relay R and its sounder G at the foreign station, and it will be seen
that the relay S is also connected with the sounder G. In order to
explain this latter mode of connection it will be assumed that a signal
is being transmitted from key B of home station to sounder G of the
foreign station.
On depresing the key B the magnet of transmitter J places its
armature lever a¹ on its front stop; the battery current along wire, as
arrow No. 1 reaches the back stop of relay J, thence proceeds upward

page_text: and finding resistance at rheostat No. 2 goes in the opposite direction
therefrom, as indicated by arrow 14, to the lower surface or bar of
armature lever a¹, thenc to the front stop and beyond as indicated by
arrow No. 15, and so on as before described, one portion of the current
going to tlie main wire and the other to ground. On reaching the
foreign station the force of the current being 150 (rheostats Nos. 1 and 2
being both cut out) it passes through relay T, and acting on relay S
places its armature on the front stop. The sounder G and its local
battery is connected as by wire shown in dotted lines to the front stop
of relay S, and also to its armature lever, and when the armature is thus
brought forward it permits the sounder G to operate. If while key B
was closed key A should also be closed, the current being thereby cut off
entirely, the relay S will of course release its armature, but simul-
taneously the relay R will also release its armature to the back stop,
and thus the control of sounder G is transfered from relay S to
relay R.
The "cut outs" or shunts M and N are of service only when it is
desirable that the ground rheostats Nos. 5 and 6 be wholly cut out.
When relays O and R are operated as has before been stated the battery
force has been reduced to zero, at which time the magnets of the "cut
outs or shunts M and N release their armatures, which pass to their
back stops, and through their levers communication is opened by wire
shown in dotted lines from ground wire to ground wire on opposite sides
of the ground rheostats 5 and 6.
"
2
When operating two keys and transmitting two messages over the
lin in the same direction, the messages may both be dropped at any
number of intermediate stations if these latter are provided with
sounders and relays of the general character of those herein described.
.
It will be seen that the rheostats 1, 2, 3, and 4 serve only as means
for dividing the power of the battery into requisite divisions or parts.
It will also be seen that for service under one condition I reduce the
power of the battery with reference to the main line to zero. Under
another condition I reduce it to 50; under another condition to 100,
and under still another I employ the full force of the battery, i.e. 150.
Now I am well aware that if a battery of 12 cups has a power of 150,
that 8 cups will have a power of 100, and 4 cups a power of 50, and
therefore I well know that by the employment of a battery of, say, that
,

page_text: number of cups, and an arragement of shunts or switches which will
be readly suggested to persons skilled in the art, they may be connected
with transmitters in such a manner that the battery force to line wire
may be varied to the same extent and in substantially like manner as
herein shown to be accomplished by rheostats No. 1, 2, 3, and 4.
For the purpose of showing that the rheostats which in connection
with the transmitters serve as means for reducing the power of the
battery to line may be dispensed with by employing, say, a battery
divided into three divisions, each having a power of 50, which when
properly connected will transmit 150, 100, or 50 to line, or be capable
of being wholly cut off when a zero of power is required.
I will now describe the form and arrangement of apparatus shown by
Figs. 5 and 6. I will first refer to the transmitting apparatus shown in
Fig. 5. The keys are shown at A¹ and B', each with local battery u¹.
Key A' is connected to transmitter I', and key B¹ to transmitter J¹, as
before described.
The battery is in three divisions, which are plainly designated in the
Drawings, and are respectively numbered 1; 2, and 3. These divisions
are so connected with each other that when two or three of them are.
employed they act as one battery in every respect.
The transmitters I and J' have armature levers which are provided
in each instance with a plug, as at c, composed of good insulating
material. Each plug has a wedged-shaped face, and a small metal
plate therein, which is connected to a wire wich extends through the
plug longitudinally. Opposite each plug is a pair of union springs, as
at d and d¹, which serve as electric connections for the wires attached-
thereto. When the plug c enter between these springs they are forced
apart, breaking their connection, and each communicates with a metal-
plate and one of the wires. The back stops of transmitters I' and J¹ are
connected by wire e.
When the apparatus is in the condition as shown in the Drawings
two of the divisions of the battery, Nos. 1 and 2, arc in connection with
the main line, which when the apparatus is at rest may be represented
as 100.
The battery divisions connect as follows:-Division No. 1 by way of
wire clearly shown to one side of union spring d, thence through plug in

page_text: armature lever of transmitter I' to division No. 2, with which it properly
connects, and from the other end of this battery No. 2 continues by
wire back through the plug and the opposite side of union spring d along
wire to union spring d³, thence back by wire g to rear end of the
armature lever of I', thence to its back stop to the back stop of armature
J¹ by wire e, and thence to line with power of 100 received through the
proper connection of two batteries, each having power of 50. Now it is
to be remembered in connection with the form of apparatus previously
described that we require at the transmitting end of the line the
following conditions :-Normally battery power to line 100. When
key A' is operating separately we require power to line 50. When
key B' is operating separately we require power 150, and that when
both keys are operated simultaneously we require zero. Now it is to
be understood that one of the "cut outs or shunts M or N of the
previous Figures is to be also employed with the transmitters I¹ and J¹
of this Figure, and in precisely the same connection, and that at the
other end of the line V₁ either set of the relays previously shown may
be connected thereto.
"
I will first show how a signal may be transmitted from key A¹ to a
sounder like F through a relay like Q of the previously described
apparatus. To do this the power on the line must be reduced to 50;
key A¹ being depressed the armature lever of I¹ is carried to its front
stop. The withdrawal of the plug c from union spring d takes
division No. 2 of the battery from the line; the two sides of spring d
being in contact maintain connection of division No. 1 of the battery
with the main line, and therefore the proper relay at the other end of the
line will release its armature, and so operate the sounder. The current
under these circumstances passes from division No. 1 of the battery to
the main spring d, crosses to wire f, thence to wire g; having no outlet
at armature lever of transmitter I¹, it being on front stop, the current
passes from wire g by way of wire h to rear end of armature lever of
transmitter J¹, thence through its back stop to line wire.
I will next show how a signal may be sent from key B¹ to a sounder
like E, through relays like O and P of previous Figures. It has already.
been explained that either zero or 150 will operate that sounder. Key B
being depressed causes armature lever of transmitter J to move to its front
stop, and in doing so its wedge block c separates union spring d², and brings
division No. 3 of the battery into connection with wires f and g, so that

page_text: the full current from the two divisions Nos. 1 and 2 of the battery joins
with that of division No. 3, and thus augmented passes backward on
wire g to rear end of armature lever of transmitter I', thence through
its back stop by wire e to back stop of transmitter J¹, thence to line
wire V¹ with a power of 150.
I will next explain how signals may be transmitted simultaneously
from both keys to their respective sounders. It has already been
described in connection with previous Figures that sounders E and F
may both be operated simultaneously, because sounder E is operated
through an armature in a relay, which releases it when at zero, and
sounder F is operated by a relay which releases its armature at 50, and
this battery relay will therefore of course perform in the same manner at
zero.
It will be seen that when the armature lever of transmitter I' is on
its front stop the division No. 2 of the battery is cut out entirely.
The current from division 1 proceeds through union spring d to union
spring & per wire f. The armature lever of transmiter J' being down
the current passes on the wire through the plug to division 3 of the
battery, and joining with its current passes through the opposite side
of the plug to opposite side of spring d¹, thence by wire g to rear end of
armature lever of transmitter I', which being down has no connection
with its back stop, wire e, and line wire, and therefore it completely
cuts off the divisions Nos. 1 and 3 of the battery (No. 2 being already
cut off), and the condition of the line wire is reduced to zero, and the
two sounders respond. While both keys are being thus simultaneously
operated if key A¹ be alone released the armature lever of I' falls to its
back stop, which puts division 2 of the battery into connection with the
current from divisions 1 and 3 by wires f and g to rear end of armature
lever of transmitter I', thence through its back stop, and via wire e to
back stop of transmitter J¹, thence to line. at 150. If on the other
hand key B¹ be alone released armature lever of J¹ falls to its back stop,
cutting out division 3 of the battery. The armarture lever of I¹ being
on its front stop division No. 2 is also cut out, leaving division No. 1 in
connection with the line at a power of 50.
There are numerous other modes of effecting the direction of the force
of the battery to line in three unequal powers, which may be employed
with still other means for wholly cutting them off from the line, one of
which is shown in Fig. 6.

page_text: As in Fig. 5 the battery is divided into three divisions, Nos. 1, 2,
and 3, neither of these divisions is short circuited. When at rest
division 1 sends its current to rear end of lower insulated portion of
armature lever of transmitter I², thence by wire i through division.2 of
battery, thence by wire k to back stop through end of the upper
insulated portion of armature lever of transmitter. I, thence by coil
wire 1 to wire m, thence to rear end of armature lever of transmitter J³
along it, and through its back stop to line with power of both divisions
of battery, i.e., 100. When through key A² armature of I³ is depressed
it cuts out division 2 of battery, and power of division 1 passes through
front stop to wire m, thence as before with a power of 50. When
through key B² armature of J' is depressed its lever is brought into contact
with its front stop, carrying power from divisions 1 and 2 through
division 3 of battery by way of wires n and o to line with power of 150.
When both keys actuate simultaneously the armatures of both trans-
mitters to their front stops, division 2 is cut out, and divisions 1 and 3
with power of 100 proceeds to switch W, where it is cut off, entirely
reducing the battery power to line to zero. This switch W may be com-
posed, as shown, of two magnets, which operate on one armature lever ;
neither magnet alone will actuate it, but both will do so, and so cut off
the line entirely. These magnets are respectively connected with onė
of the keys and its usual local battery, and therefore when both keys
are depressed the switch is opened, but neither key separately can

page_text: 2rd. The combination with the line wire, its batteries, suitable
conductors, two keys and their batteries, two transmitters, two rheostats
controlled by the transmitters, and a cut out or shunt, of three relays
with armatures variously weighted, and two sounders with local batteries,
substantially as described..
3rd. The combination of two keys and their local batteries with a
transmitter capable of performing the usual service, a transmitter having
an armature lever composed of insulated bars or plates, two rheostats, and
a system of connecting conductors, substantially as described, whereby
a desired portion of the battery current may be witheld or sent beyond
the transmitters, or the entire current cut off..
4th. The combination with a ground wire and its rheostats of an
automatic shunt or "cut out" composed of an electro-magnet, an
armature lever, and the usual back and front stops, a battery wire which
charges the magnet, a conductor which connects the armature and one
of its stops to the ground wire on opposite sides of its rheostat, and a
means for cutting off the current from the battery to the magnet of the
shunt, substantially as described.
5th. The combination with a sounder and its local battery of two
relay magnets, with armatures variably weighted and arranged to
separately operate the sounder when call is made thereon from its
proper transmitting key, substantially as described.
6th. The combination with a sounder having a local battery, and a
relay which normally holds its armature lever to its front stop with but
little magnetic power, and operates the sounder from its back stop, of a
second relay which is electrically connected to the first, holds its
armature to its front stop with a greater force, is located between the
first relay and the line wire (which charges the magnets of both relays),
and is arranged to shunt the current received by it to the ground wire,
substantially as described, whereby the weaker relay may be protected
in the performance of its duty when its sounder is called to respond to
its proper key.
7th. In a transmitter, the combination with an electro-magnet and
the usual front and back stops of an armature lever composed of two
separate bars or plates, insulated from each other, and constituting two
distinct surfaces for engaging with the stops, substantially as described,

page_text: whereby each bar or plate of the armature may serve as an independent
conductor, as set forth.
In witness whereof, I, the said Martin Benson, have hereunto set
my hand and seal, this Eighth day of June, in the year of our
Lord One thousand eight hundred and seventy-six.