Improvements in Telegraphic Transmitting, Receiving and Translating Arrangements.
Year: 1899

page_text: Improvements in Telegraphic Transmitting, Receiving and
Translating Arrangements.
I, ALEXANDER MUIRHEAD, of Sherborne Lodge, Shortlands, in the County of
Kent, D.Sc., Telegraph Engineer, do hereby declare the nature of this invention
to be as follows:-
"
My invention relates to the transmission reception and translation or re-trans-
mission of telegraphic signals. It has for its objects to provide means for re-
transmitting signals received from one circuit on to another circuit in such
manner that local transmitters are dispensed with and the apparatus thereby
simplified; to provide means for preserving the zero of the organization and to
improve the character of the local contacts; to provide means for automatically
curbing the movements of the signal coil or some equivalent part of the receiv-
ing circuit, whereby the character of the signals re-transmitted is improved, and
generally to effect the improvements hereinafter indicated.
+6
33
Being more particularly applicable to submarine cable circuits I will describe
my invention in connection therewith, but it is to be understood that such
invention, by obvious modifications, can be applied to other electrical circuits.
Signals sent through submarine cables are generally received on the well-known
Kelvin siphon recording instrument. The suspension-piece of this instrument
comprises a signal coil suspended between the poles of either a permanent magnet
or an electro-magnet and an ink siphon carried by an aluminium cradle which is
supported by a stretched phosphor-bronze strip or wire. Extending between the
signal coil and the cradle are two fibres which together with the stretched strip or
wire and the fibres or strip supporting the signal coil form the mechanism which
gives directive force to the said signal coil. In practice when the coil is joined
to a cable circuit its position in the magnetic field in which it is suspended is
constantly changing during signalling and it is also liable to change from the
influence of earth currents.
My present invention in the first place consists essentially in the utilization of
the whole or a portion of the means which imparts directive force to the recorder
coil, or to that part of the receiving instrument which is actuated directly by the
cable current, in order to effect the translation or re-transmission of correspond-
ing electrical impulses or signals into the second line or cable. The arrangement
can be attached to any existing siphon recorder or if a record of the signals pass-
ing through from one section of cable to another is not required manifestly the
017

page_text: ink siphon and its appurtenances can be dispensed with, and the suspension-piece
modified in accordance with this invention in the following manner.
The two fibres which extend in the siphon recorder from opposite corners of
the recorder or signal coil to the aluminium cradle are connected to two elastic
strips of phosphor-bronze or other suitable material which are also connected by
two similar fibres to a second coil located between the poles of a second magnet.
The second coil may either be suspended in the same manner as the recorder or
signal coil or be pivotally mounted. Supported on the second coil, and loosely
mounted either on the same axis or on an independent axis is a well-insulated
contact arm or tongue whose freedom of movement is regulated by a pressure
spring and screw-head or like device. This tongue plays between the terminals
of a split battery and is in electrical connection with the cable into which
signals are to be retransmitted. Whenever an impulse from one cable actuates
the signal coil the resultant movement is communicated to the second coil and the
tongue thus brought into contact with one or other of the local line battery ter-
minals whereupon a corresponding impulse is sent into the cable which is con-
nected to the tongue.
It is essential to my invention that a constant tremor or vibration be imparted
to the local contact tongue either indirectly through the signal coil, or diectly
through the second coil on which it is generally mounted and held by friction
irrespective of the movements brought about by the current from the cable. I
accordingly join up one, or other of these coils to the circuit of an alternator. The
constant vibration of either of the said recorder coils causes the tongue to come
successively into contact with the local line battery terminals between which it
plays but such contacts with the battery are made too rapidly to affect the receiv-
ing instrument at the distant end of the cable which is connected to the tongue.
The result of this rapid vibration of the tongue against the battery terminals is
to cause it to vary its position relatively to the coil or support upon which it is
mounted and to maintain a mean position between the said battery terminals
whatever may be the movements of the coil or support to which it is attached
and however the zero" position of the signal coil may vary. Upon a signal
arriving from one cable the signal coil in connexion therewith-and through it
the second coil-will, while vibrating, be deflected, putting the local contact
tongue into effective contact with one or other of the local line battery terminals
and so transmitting an impulse in one or the other direction into the cable which
is connected to the local contact tongue. Sometimes instead of vibrating the
recorder coils to which the vibrating contact tongue is attached, directly or indi-
rectly, I vibrate the base itself on which the contact tongue is loosely mounted
and held, by friction.
In a modification of this arrangement the signal coil is subjected to the influ-
ence of the alternator and its tremors transmitted to the flexible metallic strips,
these metallic strips vibrate against the extremities of a light cross-bar of alumi-
nium or other suitable material pivotally mounted in a manner similar to the local
contact tongue above described. A local battery is joined up to the second coil
(in this case differentially-wound) and its circuit completed through the said cross-
bar and the flexible strips. The advantage of this arrangement, in comparison
with that above described, is that the current from the cable is only called upon
to actuate the signal coil and its immediate connexions, and not to overcome the
inertia of the second coil, and its local contact tongue. By mounting pieces of
well-polished graphite on the cross-bar and the directive springs at the points
where they come into contact a greater and more uniform variation is produced
in the circuit of the second coil especially when the signal coil is limited in its
movements by being subjected to a strong controlling force.
A still simpler arrangement is one in which the second coil is dispensed with
and the vibrating tongue is mounted as already described upon the same axis as
the cross-bar (and insulated therefrom) instead of upon the second coil; in this

page_text: case the two flexible strips. are connected to the two opposite poles of the local
split line battery, the cross-bar is connected to earth, and the tongue to line
as before:
"
Another means of communicating the effect of the cable currents to. the vibrat
ing tongue, and in a magnified manner, is to introduce between the signal coil
and the circuit of the second coil a variable resistance as part of a differential or
Wheatstone bridge arrangement and to cause the elastic metallic strip (which is
kept in constant vibration as before) to come into contact more or less in accord-
ance with the movements of the signal coil, with the surface of a conducting mass
(made preferably of a mixture of carbon and kaolin) on either side of the point
at which the strip is fixed. Or a suitable spiral of very fine closely-wound plati-
num silver or manganin alloy wire supported on a cylinder of ivory or other
insulating material may be substituted for the rod of carbon; the lapping upon
which spiral of the vibrating elastic strip short-circuits a greater or less number
of its helices on one side or other of the middle of the strip, thus upsetting the
balance of the Wheatstone bridge composed of the two halves of the carbon mass
or spiral of metallic alloy on either side of the centre of the strip and the two
resistances of the Wheatstone bridge arrangement and actuating the second coil
which is included in the arrangement.
«
In cases where the cables are duplexed "I may produce a curbing effect upon
the movements of the signal coil or other portion of the arrangement which is
actuated by the cable current by connecting such coil or its equivalent through an
overflow wire or connection through a resistance between a separate circuit on
the said coil and two suitable points of the artificial cable. By this means a
current in the reverse direction to that which had last actuated the mechanism
is sent at the proper time and of correct strength through the coil thus "curb-
ing" or hastening the return of the coil to the zero position after each signal.
Or the "overflow" from the artificial line may be arranged to break the circuit
between the cable and the signal coil by passing it through a separate coil pro-
vided with directive springs and a cross-bar in the manner to be described below
with reference to another part of this invention. Instead of the artificial line
an equivalent circuit made up of one or more self-inductance coils may be sub-
stituted. Sometimes in conjunction with the "overflow" circuit from the arti-
ficial line, whenever directive springs are employed between the signal coil and
the second coil, the cable is connected to the signal coil through the two directive
springs and the cross-bar against which the springs rest. On the deflection of
the signal coil in one direction or the other beyond a certain amount the circuit
with cable is broken and the return of the signal coil to zero thus hastened.
Or when no directive springs are made use of between the signal coil and the
second coil or the platform on which the vibrating tongue is held by friction I
insert between the vibrating tongue and the cable to which it is connected a
separate coil similar in construction to the signal coil and tied to two directive
springs which in their normal position rest on a cross-bar in the manner above
described; the cable being connected to the signal coil through the directive
springs and the cross-bar as before. In connexion with this arrangement I may
employ self-inductance coils or a portion of artificial line or other retarding
means to delay the breaking of the circuit between the cable and the signal coil.
Or the same result may be produced by inserting one circuit of a suitable trans-
former between the middle of the local split line battery and earth and either
applying the other circuit of the transformer as a shunt to the signal coil or
inserting it between the cable and the signal coil.
A hand signalling key or an automatic transmitter may be included in the
system as a means of communication between the intermediate station and either
of the distant stations. The combination of a transmitter with a constantly.
vibrating coil and a suitably-mounted tongue vibrating between the terminals of
a split battery would constitute a very effective arrangement for diminishing the

page_text: "
jar" produced on the receiving instrument when signalling on duplexed cables
apart from the idea of re-transmission from one section of cable to another.
In order to assist the making of firm contacts between the transmitting con-
tact-making device and the terminals of the local line battery which is very
essential to efficient working, I may wind an extra circuit of very few turns on
either the signal coil or the second coil or on both coils and insert the same, (in
series with a condenser and both suitably shunted), between the tongue and the
cable in connexion therewith so that all outgoing currents from the local line bat-
tery pass in the direction to achieve the object in view. Or this extra circuit of
the coil with a condenser in series therewith and a shunt may be inserted between
the middle of the split line battery and earth. For the same purpose I may
employ another arrangement in which a third coil is inserted between the second
coil (in this case differentially-wound) and the local re-transmitting battery. The
contact stops of the battery employed in connexion with the third coil in this
arrangement are preferably made of well-polished graphite and the tongue is
tipped with the same material where it comes into contact with the carbon bat-
tery stops. The tongue of the third coil through the carbon battery stops and
the two circuits of the differentially-wound second coil of suitable resistance
forms a complete and continuous differential circuit with a suitable battery. On
the passage of a current from the cable through the signal coil the third coil is
deflected in one direction or the other and pressure brought to bear upon the
corresponding contact stop through the vibrating tongue.
The effect of the
variation of pressure on these contact stops is to cause a corresponding varying
current to flow through the second coil which actuates its tongue in one direction
or the other against the terminals of the retransmitting battery.
Sometimes in place of the carbon contact stops on either side of the vibrating
tongue I employ two closely wound spirals of carbon or of an alloy of high specific
resistance connected to the tongue and to the battery terminals.
Obviously the rapid vibration of the coil or coils made use of in carrying out
this invention may be attained by other means than the alternator hereinbefore
referred to. For example an automatic make-and-break arrangement might
be employed consisting of a coil pivoted or suspended between the poles of a
permanent magnet and carrying a tongue which plays between the terminal
contacts of a split battery. The tongue is connected to one end of the circuit
of the coil. If the circuit of this automatic make-and-break be completed
for example through the second coil of the above described arrangements the
tongue will be in constant vibration between the terminals of the split battery
sending an alternating current from the battery through the second coil. A shunt
from the coil to the middle of the battery is required in this arrangement for the
purpose of regulating the strength of the alternations.
Or sometimes the second coil itself joined up to the vibrating tongue in the
manner above described and its circuit completed through the cable to which the
tongue is usually directly connected and earth may take the place of the alter-
nator in the arrangements above described. In this case there will be an extra
circuit on the second coil to be inserted between the middle of the local line bat-
tery and earth in the manner and for the purpose already described.
Obviously, also, instead of causing a pivotally mounted tongue to vibrate
between stationary terminals, I may similarly mount an arm carrying the terminals
of the split line battery upon the second coil or other vibrating supporting body
and fix the contact tongue upon the signal coil. Or, further, I might fix the arm
carrying the line battery terminals on the second coil and pivotally mount the
vibrating tongue upon the signal coil as before. Sometimes I may dispense with
the elastic strips and connect the signal coil directly to the second coil by two
fibres. In this case the two circuits of the signal coil will be connected one to the
cable and to the alternator and the other to the "overflow" from the artificial
line and the second coil suitably arranged inserted between the vibrating tongue
and the cable into which re-transmission takes place in the manner above described.

page_text: Sometimes the second coil may be dispensed with and the vibrating tongue
either loosely mounted and held by friction on the signal coil itself or on a
separate body which is tied to the signal coil by fibres and which is, in some cases,
vibrated independently of the signal coil.
1041
f A 1000
A. F. SPOONER,
323, High Holborn, London, Agent for the Applicant.
Improvements in Telegraphic Transmitting, Receiving, and
Translating Arrangements.
I, ALEXANDER MUIRHEAD, of Sherborne Lodge, Shortlands, in the County of
Kent, D.Sc., Telegraph Engineer, do hereby declare the nature of this invention
and in what manner the same is to be performed to be particularly described
and ascertained in and by the following statement: —
My invention relates to the transmission, reception and translation or re-trans-
mission of telegraphic signals. It has for its object to provide means for re-
transmitting signals received from one circuit on to another circuit in such manner
that local transmitters can, if desired, be dispensed with and the apparatus
thereby simplified; to improve the character of the local contacts; to provide
improved means for preserving the zero of the organization and for automati-
cally "curbing" the movements of the signal coil or some equivalent part of the
receiving circuit or (when local transmitters are employed) of actuating curbing
mechanism, whereby the character of the signals re-transmitted is improved, and
generally to effect the improvements hereinafter indicated.
"
"
Being more particularly applicable to submarine cable circuits I will describe
my invention in connection therewith, but it is to be understood that such inven-
tion, by obvious modifications, can be applied to other electrical circuits.
In the accompanying drawings:
Figure 1 shows in perspective that part of a siphon recording instrument
designated the "suspension-piece" as now generally constructed; Figure 2 is a
similar view of a suspension-piece with additions whereby it is adapted for the
purpose of my present invention; and Figures 3 to 19 are diagrams illustrative
of my invention.
Signals sent through submarine cables are generally received on the well-known
Kelvin siphon recording instrument. The suspension-piece of this instrument
comprises a signal coil 1 suspended between the poles of a permanent or other
suitable magnet (not shown in Figure 2) and an ink siphon 2 carried by a cradle 3
which is supported by the stretched phosphor-bronze strip or wire 4, 4.
Extend-
ing between the signal coil 1 and the cradle 3 are the two fibres 5, 5 which,
together with the stretched strip or wire 4, 4 and the fibres supporting the signal
coil 1, form the mechanism which gives directive force to the said signal coil,
The normal or "zero" position of the coil 1 between the poles of the magnet N.S:
is that indicated in the diagrams but in practice when the coil is joined to a
cable circuit the mean position of the coil is constantly changing during signalling
and is also liable to change from the influence of earth currents.
My present invention in the first place consists in the utilization of the whole
or a portion of the means which imparts directive force to the recorder coil, .or
to that part of the receiving instrument which is actuated directly by the cable
current, in order to effect the translation or re-transmission of corresponding

page_text: electrical impulses or signals direct, into the second line, or cable that, is, to, say
without the intermediary of local transmitters and their batteries. The arrange
ment can be attached to any existing siphon recorder, or if a record of the signals
passing through from one section of cable to another is not required manifestly
the ink siphon and its appurtenances can be dispensed with, and the suspension-
piece modified in the manner substantially as shown in Figure 2. Or when the
sections of cable are duplexed, records of what is being received at the distant
stations may be obtained by connecting up siphon recorders at the far ends of the
artificial lines.
In all the applicable diagrams 6 represents the cable from which for the pur-
pose of this description it is assumed signals are about to be received and 7 the
one into which corresponding signals are to be re-transmitted. 8 (see Figures 3,
5, 6, 7, 12, 14, 15, 16 and. 17) is the artificial cable required for the purpose of
duplex working: 9, 9 represent the condensers which are usually placed between
the cable: and the receiving or sending apparatus; and E, E represent the earth
connexions. 26, 26 represent resistances inserted for the purpose of regulating
the strength of the current flowing in the various circuits. It will be understood
that by means of a switch the connexions, in the case of simplex working, may
be changed over so that the cable 7 is connected to the coil 1 and the cable 6
to the tongue 13 or alternatively the apparatus between each section of cable may
be duplicated for the same purpose. In the case of duplex working the apparatus
must be so duplicated as shown in Figure 12. When the two sections of cable at
intermediate stations are duplexed and the two sets of apparatus are joined up
according to this invention transmission can take place automatically whether
on duplex" or, "simplex" working.
.6
I will first describe the nature of the additions.to the suspension piece so far
as they are included in Figures 2 and 3 but which in themselves from no part
of my present invention. Two fibres 5, 5 extend from opposite corners of the
coil 1 to two suitable elastic phosphor-bronze or other metallic strips or springs 10,
10. Two other fibres 11, 11 (similar to those marked 5) extend to a second coil 12
(similar to the coil 1 and located between the poles of a second magnet) which
may either be suspended in the same manner as the coil 1 or be pivotally
mounted as shewn in Figure 2. Supported on the second coil 12 and indepen-
dently mounted either on the same axis, or on an independent one is a well-
insulated tongue 13 whose freedom of movement on its support relatively to the
said coil is regulated by a pressure spring 14 (see Figure 2) and screw-head 15
or like device: The tongue 13 plays between the terminals 161, 171, either fixed
oscillating or revolving, of a line-battery 16, 17 and is in electrical connection
with the cable 7 into which signals are retransmitted either directly or through
local transmitters. Whenever an impulse from the cable 6 actuates the coil 1
the resultant movement is communicated either directly or indirectly to the
coil 12, and the tongue 13 applied to one or other of the battery terminals 161,
17 whereupon a corresponding impulse is sent either direct into the cable 7 and
without the intermediary of local transmitters and their batteries (see Figures 3,
4, 5; 8. 9, 11, 12, 13, 17 and 18) or through local transmitters (see Figures 6,
7, 14, 15 and 16).
It is essential to my invention, in cases where the "shifting zero" difficulty is
troublesome,, that a constant' tremor or vibration be imparted to the relay tongue
or local contact-making device, either directly by vibrating such device itself or
indirectly by vibrating one or other of the coils or any other base on which the
said, contact-making device is mounted and frictionally held or rests upon, irre-
spective of the movement of the signal coil brought about by the currents from
the cable. Or the tongue may be fixed to its support and the battery terminals
frictionally mounted upon a support (see 40 Figure -17). This vibration also
serves to reduce or obviate cohesion between the surfaces of contact of the relay
and the battery terminals. I accordingly join up one or other of the said coils
or some other suitable part of the organization to the circuit of an alternator 18:

page_text: The constant vibration of either of the said recorder coils (in the case of Figure 3
it is the one marked 12) causes the tongue 13 to come successively into contact
with the battery terminals 16 and 17 but such contacts with the battery are
made too rapidly to affect the receiving instrument at the distant end of the
cable 7. The result of this rapid vibration of the tongue 13 against the battery
terminals 16 and 17 is to cause it to vary its position relatively to the coil or
support upon which it is mounted and to maintain a mean position between the
said battery terminals whatever may be the movements of the coil or support to
which it is attached and however the "zero" position of the signal coil may vary.
Whenever local transmitters are employed these vibrations are damped down by
inserting a sufficient amount of retardation of artificial line or of self-induction
between the vibrating tongue and the local transmitter; or when the local trans-
mitters employed are of the recorder coil form the required damping may be
effected by winding the coils of the transmitters on metal frames as in the well-
known dead-beat d'Arsonval or recorder coil galvanometers.
Upon a signal arriving from cable 6, the coil 1-and through it the coil 12–
will, while vibrating, be deflected, putting the tongue 13 into more or less effec-
tive contact with one or other of the battery terminals 16 or 171 and so trans-
mitting an impulse in one or the other direction into the cable 7 as already
described. It will be understood that the fibres 5 and 11 are taut, being in ten-
sion against the flexure of the metallic directive springs 10.
"
29
In cases where the shifting zero is not troublesome it is unnecessary to
vibrate the relay tongue against stationary terminals; it is sufficient simply to
mount the contact tongue or the relay tongue upon the coil and to vibrate the
battery terminals which are supported on a vibrating body. Such a vibrating
arrangement is shown at V in Figure 8; or as shown in Figure 15 the said battery
terminals may be mounted upon a vibrating spring W placed in front of an
electromagnet Y which is included in the circuit of the vibrator V. The vibrat
ing plate that forms the terminals may be a flat one as shown or preferably its
surface is shaped to the arc of a circle.
Alternatively the tongue may rest or vibrate upon a carbon or like wheel or
roller that forms part of a Wheatstone bridge arrangement.
In the arrangement depicted in Figure 3 it will be observed that the move-
ments of the coil 1 occasioned by the currents from the cable G are transmitted,
by the taut fibres 5 and 11 and the flexible springs 10, to the second coil 12
which second coil is constantly being vibrated by the alternating current of the
alternator 18. In Figure 4 a modification of the arrangement of Figure 3 is
shewn, in which the coil 1 is subjected to the influence of the alternator 18 and its
tremors transmitted to the flexible metallic springs 10; these metallic springs
vibrate against the extremities of a light cross-bar 19 of aluminium or other
suitable material pivotally mounted-in a manner similar to the tongue 13-at
the point 20. A local battery 21 is joined up to the second coil 12 (in this case
differentially-wound) and its circuit completed through the said cross-bar 19 and
the flexible springs 10. The advantage of this arrangement, in comparison with
that described with reference to Figure 3, is that the current from the cable 6 is
only called upon to actuate the coil 1 and its immediate connexions, and not to
overcome the inertia of the second coil 12 and its tongue 13. By mounting
pieces of well-polished graphite on the cross-bar 19 and the directive springs 10,10
at the points where they come into contact a greater variation is produced in the
circuit of the coil 12 especially when the signal coil 1 is limited in its movements
by being subjected to a strong controlling force.
"The two poles of the retransmitting line battery 16, 17 may in some cases, as
shown in Figure 4, be joined to two springs 41, 41 which play between the ter-
minals 161, 17 respectively and the central stop 42 forming what is known as a
reversing key or pole-changer.
A further modification is that depicted in Figure 5 where the tongue 13 is
mounted as already described upon the same axis as the cross-bar 19 (and insu-

page_text: lated therefrom) instead of upon the second coil as before; in this case the two
flexible springs 10 are connected to the two opposite poles of the split line
battery 16, 17, the cross-bar 19 is connected to earth, and the tongue 13 to line
as before.
The sensitiveness of the previous organization may be increased by relieving
the signal coil 1 or the second coil 12 of the work of making firm contact between
the vibrating tongue 13 and the terminals of the line battery by adjusting the
tongue 13 to vibrate on a metal plate or cylinder that constitutes the contacts, 161
17 as shown in Figure 5. The tongue 13 is kept in its zero position by vibrating
against two fixed stops x, y.
In some cases when the metal plate that constitutes the contacts 161, 17' is
employed it is unnecessary to retain the fixed stops x, y, and the said metal plate
may be caused to vibrate either approximately parallel with the length of the
tongue 13 or at right angles thereto.
The amount of "jar" or vibration which is communicated to the contact tongue
in this arrangement by the vibrating contact plate on which it rests is sufficient
for the purpose of this invention to keep the contact tongue in correct position
relatively to the coil on which it is supported when the "shifting zero is slight.
In order to diminish the cohesion between the surfaces of contact of the relay
tongue and the battery terminals there may be substituted for the stationary ter-
minals generally employed in relays two revolving contact wheels such as those
referred to in the Specification of English Letters Patent No. 1867 of A.D. 1866.
granted to C. & S. A. Varley. These revolving contact wheels are preferably
made of gold or silver or other decohering metal and are shown at 16, 171 in
Figures 3, 6, 12, 13, 14 and 16. To prevent the tongue 13 from being jarred
it is sometimes adjusted to rest firmly on the surface. of a third revolving
metallic wheel 61 (see Figures 3, 12 and 13) preferably mounted on a horizontal
axis and beneath the other two revolving contact wheels 161, 171.
Figure 6 represents a modification of the arrangement of Figure 5 in which the
directive springs 10, 10 are made to rest on the two revolving contact wheels 161
17 and to keep the circuit between the local battery 21 and the coils of the non-
polarized transmitter X closed. The cohesion between the springs 10, 10 and the
contact wheels is greatly diminished and the contacts improved when the wheels
are rotated.
"
"
A further variety of this arrangement is illustrated in Figure 7 wherein the
springs 10, 10 project vertically from the two separate insulated bases. The free
ends of the springs are attached by the fibres 5, 5 to the coil 1. Instead of the
two revolving contacts of Figure 6 only one contact 163 is employed and the
adjustment may be such that with the coil 1 in its zero position both springs
are clear of the roller 16, any sufficient movement of the coil bringing one or
other of the springs into contact with the surface of the said roller. Alterna-
tively the arrangement may be such that normally both of the springs 10, 10 are
touching the roller 16, any deflection of the coil 1 allowing one of them to spring
free from the said roller.
Another means of communicating the effect of the cable currents to the vibrat-
ing tongue 13, and in a magnified manner, is to introduce between the coil 1 and
the circuit of the coil 12 a variable resistance as part of a differential or Wheat-
stone bridge arrangement as shown in Figures 8, 9, 10, 11 and 18. In Figure 8
the elastic metallic spring 10 (which is kept in constant vibration as before) is
caused to come into contact more or less in accordance with the movements of
the coil 1, with the surface of a conducting mass 22 (made preferably of a mix-
ture of carbon and kaolin) on either side of the point at which the spring 10 is
fixed. Or, as shown in Figure 9, instead of vibrating directive springs on the
surface of a fixed conducting mass 22, the latter is revolved and a tongue 10*
(similar to the one 13) tied by fibres 5, 5 to the signal coil 1 substituted for the
directive springs. The tongue by its movements on the surface of the revolv-

page_text: ing mass 22, in response to the movements of the signal coil, creates as before
corresponding variations of current in the coil 12 of the Wheatstone bridge
arrangement which is composed of the cylindrical mass 22 on either side of
the tongue 10 (or the springs 10, 10 of Figure 8) and the two resistances 221, 221.
In the case of Figure 9 the tongue 10 may be a fixed one and when vibration
is required an alternator is connected to the coil 12.
Sometimes instead of the uniform cylindrical mass 22 in Figure 9 I build
up the revolving cylinder of a series of thin metallic plates or discs separated
by disc of mica or other suitable insulating material and between each metallic
disc I insert a resistance coil of suitable amount to form the differential circuit or
Wheatstone bridge series of resistances required for the purpose of this invention.
Figure 10 illustrates diagrammatically on an enlarged scale the essential parts
of this modification a representing the metallic plates or discs, b the insulating
discs, and c the resistance coils. It will be understood that this diagram only
show's the Wheatstone bridge circuit, the remainder of the arrangement may be
the same as Figure 9.
Alternatively the arrangement of Figure 11 may be adopted wherein the
longue 10 is loosely mounted on the coil 1 and is caused to vibrate on the
roller 22. This figure illustrates a vibrator 18* employed in lieu of the alter-
nator, and the tongue 10* terminates in an ebonite or like hammer head 10**
whilst the cylindrical roller has side flanges 22. In this arrangement it is not
necessary when the "shifting zero is slight that the hammer head should con-
stantly come into contact with the side flanges but merely oscillate upon the
surface of the roller 22. Should, however, a considerable alteration of the " zero
occur the hammer head 10** will hit or vibrate against one or the other of the
flanges 22 and the position of the tongue 10* will be rectified.
"
"
وو
"
Figure 12 shows a complete duplex installation on the well-known Muirhead
"double-block" plan with my present invention in one form added thereto.
In this Figure 24, 24 depict two connections with the artificial cable which I
have called the overflow," but which arrangement is not generally claimed
herein and 291, 291 are "outflow connections which are hereinafter more fully
referred to; 27, 27 are the usual low resistance rheostats employed in con-
nexion with the block condensers 9, 9 in duplex working. When a current
arrives from cable 6 it passes through the signal coil 1 and thereby deflects the
tongue 13 of the associated coil 12. A corresponding current is thereupon re-
transmitted into cable 7 from the split battery 16, 17 between the poles of which
the tongue 13 vibrates. Similarly when a current arrives from cable 7 it passes
through the corresponding signal coil 1 deflecting the tongue 13 of the asso-
ciated coil 12 and thus a corresponding current is re-transmitted into the cable 6.
The cables 6 and 7 both being connected to artificial lines 8, 8 as usual in duplex
installations, transmission can take place automatically between the two cable
sections 6 and 7 either simultaneously or in alternate directions.
66
"
In cases where the cables are duplexed" a curbing effect may, as shown
in Figure 12, be produced upon the movements of each signal coil 1 or other
portion of the arrangement which is actuated by the cable current by connect-
ing such coil or its equivalent through an " over-flow wire or connection 24
through a resistance 26' between a separate circuit on each said coil and two
suitable points at the far end of the artificial cable 8. By this means a cur-
rent in the reverse direction to that which had last actuated the mechanism is
sent at the proper time and of correct strength through such coil thus "curb-
ing" or hastening the return of the coil to the zero position after the reception
and re-transmission of each signal.
وو
In some cases it may not be convenient or feasible to utilize the "duplex"
artificial line for "overflow" or "outflow" purposes. Consequently according
to my present invention an equivalent circuit made up of self-inductance coils 25,
as shewn in Figure 13 or a separate portion of artificial line 25 as shewn in

page_text: Figures 5, 6, 7, 14, 15 and 16 or a combination of condenser and resistance as
shewn in Figure 8 may be used.
To the same end the "overflow"
may be arranged to operate upon the cir-
cuit between the signal coil and the second cable, that is the cable into which
retransmission takes place, or some equivalent part of the receiving circuit.
For instance as illustrated by Figures 6, 7, 15 and 16 the artificial, line 25 (or
as shown in Figure 14 the artificial line 25*, 25**) forms an overflow" circuit
at the end of which in Figures 6, 7 and 14 is placed a separate coil 60 (and in
the case of Figure 15 a separate coil 12) preferably of the recorder coil form
joined up in the case of Figures 6 and 7 to the tongues of the transmitter X¹
and in the cases of Figure 14 15 and 16 to a circuit, shown in dotted lines in
Figure 14 only, separate from that to which the relay tongue 13 and the revolv-
ing contact wheels 16, 171 of Figures 6, 14 and 16, or vibrating contact plate
of Figure 15, are connected. In Figure 15 the tongue 13 of the relay 12 is
shown resting on a contact plate sub-divided into three sections, the middle one
of which is connected to earth and the two outer ones 161, 17' to the poles of
the split line battery 16, 17. On the coil frame of the relay are wound two
separate circuits; one ¹, is connected through a resistance 26 to the tongue L
of the transmitter X, and the other y', y¹ to the coils of the transmitter which
form part of the overflow" or artificial line 25* circuit.
The function of this "overflow" is automatically to send on or retransmit the
correct number of separate signals to correspond with any prolonged deflexion
of the tongue 13 beyond the duration of any one signal.
"
In the case of Figures 6 and 7 on the deflexion of the signal coil 1, one or
other of the directive springs 10 leaves the corresponding contact 16 or 17'
(or the cylinder 16*) as the case may be thus breaking the circuit of one of the
electromagnets of the local transmitter X'. Thereupon a current in a corre-
sponding direction flows from the line battery into the cable 7 and also into the
overflow" or artificial line 25. This " overflow current deflects the separate
coil 60 whose tongue is connected in the case of Figure 6 to the cross-bar that
connects the contacts 101, 17' (and in the case of Figure 7 to the cylinder 16*)
and to one pole of the local battery 21 in the direction to restore the con-
nexion between the local battery and the said electromagnet. In the cases of
Figures 14, 15 and 16 the tongues of the local transmitters are adjusted to
remain over on the battery stops until a current flows from either the battery in
connexion with the tongue or from that in connexion with the relay.
Or I sometimes make use of the curbing mechanism of my automatic curb
transmitter (see Specification of English Letters Patent No. 11069 of 1894
granted to me) to actuate the reversing lever 49. In this case the curbing cam
wheel of the transmitter represented by s in Figure 16 is driven by frictional
connexion with the driving shaft of a motor and is revolved on the withdrawal
of a detent 53. The electromagnet 50 is connected to the local circuit of the
tongue 13 for the purpose of withdrawing, on the deflection of the said tongue,
through its armature, the detent 53 from the wheel s which drives the train
of the cam wheel s. The motor must be adjusted to revolve the curbing cam
as nearly as possible at the speed to correspond with the rate of transmission
adopted. Should the rate of transmission be so great that the relay tongue 13
for a succession of contacts in the same direction is held over to one side or the
other continuously, (that is for a greater length of time than that which cor-
responds to a single contact at the original transmitting station) the detent 53
will be kept withdrawn from the escapement wheel on which it acts for a
.correspondingly lengthened period and the curbing cam s allowed to revolve
until the correct number of separate contacts with the line battery is made. Or
obviously by including two electromagnets similar to 50 in the local circuit
of the transmitter X the levers of the automatic curb key referred to in the
Specification of English Letters Patent No. 1784 of A.D. 1865 granted to W.
Thomson and C. F. Varley may be operated to produce the same result.

page_text: "
In the latter cases one
overflow" serves to curb the outgoing current from
the local battery and the other to curb the movements of the signal coil.
In order to assist the making of firm contacts between the relay tongue, or
springs in connexion therewith, and the terminals of the line battery, which is
very essential to ensure efficient working, I may according to my present in-
vention wind an extra circuit of very few turns on either or both of the coils 1
and 12 and insert the same (in series with a condenser and both suitably
shunted) between the tongue 13, or springs in connexion therewith, and the
cable so that all outgoing currents from the retransmitting line battery pass
in the direction to achieve the object in view. This arrangement, termed the
outflow"
is illustrated in Figures 4 and 12 wherein the circuit may be traced
from the battery 16, 17 through the connexions 29¹ and the coil 1 or the
coil 12 to the cable 7. Or the outflow" circuit may be connected at two suit-
able points on the conductor of the artificial cable near to the beginning of the
latter in the manner shown at 291, 291 in Figure 12. A portion of the out-
going current which passes from the battery 16, 17 into the second cable and
also into the corresponding artificial line is thus diverted through the extra cir-
cuit of the signal coil or the second coil in the direction to assist in making
the contacts with the line battery firmer. Or when it is not convenient to use
the artificial line for this purpose one of the coils, say the second one 12, may
be joined up between the vibrating tongue 13 and the cable 7 and suitably
shunted by self-induction coils as shown in Figure 17 or a separate portion
of artificial line may be used instead of self-induction coils. The outflow,"
unless somewhat retarded in its effect upon the second coil by means of self-
induction or otherwise, would magnify the force of the vibrations and thereby
diminish the sensitiveness of the apparatus and the size of the signals retrans-
mitted.
66
For the same purpose, that is to ensure the making of firm contacts between
the relay tongue and battery terminals, I may employ the arrangement illus-
trated by Figure 18 in which a third coil 29 is inserted between the coil 12
(in this case differentially-wound) and the coil 1. The contact stops 30, 31 in
this arrangement are preferably made of well-polished graphite and the tongue 33
is tipped with the same material where it comes into contact with the stops 30, 31.
The tongue 3-through the stops 30, 31 and the two circuits of the differen-
tially-wound coil 12 of suitable resistance-forms a complete differential
circuit with a suitable battery 32. The tongue 13 of the second coil 12 plays
between the terminals 16', 17' of the split line battery 16, 17 as in the other
figures. On the passage of a current from the cable 6 through the coil 1, the
coil 29 is deflected in one direction or the other and pressure brought to bear
upon the corresponding contact stop 30 or 31. The effect of the variation of
pressure on these contact stops is to cause a corresponding varying current to
How through the second coil 12 which actuates the tongue 13 in one direction or
the other against the terminals 16, 17' of the re-transmitting battery 16, 17.
To improve the character of the retransmitted signals the outflow" may,
according to this invention, be utilized to bring about the reversal of the line
battery 16, 17 at the right moment during the period of each contact to produce
the clearest signal on the distant receiving instrument. This arrangement is
illustrated by Figure 5 in which the oscillating levers of two pole-changers are
shown attached respectively to the armatures of two electromagnets 50 whose coils
together with an artificial line 25 (or an equivalent series of self-inductance
coils) form the outflow" circuit inserted between the relay tongue 13 and
earth. The retardation of the artificial line 25* is adjusted in accordance with
the speed of transmission adopted so that on the deflection of the relay tongue 13
on to one terminal or the other, 16 or 171, of the line battery the portion of
the outgoing current which passes through the artificial line 25 actuates the
relay 60 in the direction, and at the right moment, to reverse the line battery
and thus to curb the current flowing into the cable most effectively.
"

page_text: Figure 14 illustrates the mode of connecting up the "outflow" for the pur-
pose of curbing the outgoing signals when a local transmitter X is employed,
In this case the electromagnet 50 reverses the line battery 16, 17 by simply
attracting the reversing lever 49 attached to its armature from the upper limit-
ing stop 51 to the lower one 52.
A hand signalling key or an automatic transmitter may according to my
present invention be included in the system with each organisation as a means
of communicating from the intermediate station to either of the distant stations.
The combination of a transmitter with a constantly-vibrating coil and a suitably-
mounted tongue 13 vibrating between the battery terminals 161, 171 would
constitute a very effective arrangement for signalling on duplexed cables apart
from the idea of re-transmission from one section of cable to another. In
Figures 3 and 12 I have shown this combination, 28 in Figure 3 indicating a
hand signalling key and 28' in Figure 12 an automatic transmitter.
Obviously the rapid vibration of the coil or coils whenever made use of in
carrying out this invention may be attained by other means than the alternator
hereinbefore referred to. For example an automatic make-and-break arrange-
ment, such as that shown for instance in Figures 13 and 19, wherein a coil 43
pivoted or suspended between the poles N.S. of a permanent magnet and carry-
ing a fixed tongue 44, which plays between the terminal contacts 45 and 46 of
a split battery 47, 48, might be employed. The tongue is connected to one
end 34 of the circuit of the coil 43 and a résistance 26 is sometimes inserted
between the end 35 of the coil and the middle of the split battery for the pur-.
pose of regulating the strength of the alternations.
66
"
In some cases I may dispense with the elastic springs 10 and directly connect
the two coils 1 and 12 by the two fibres 5, 5 as shewn in Figures 12 and 17.
In this case the two circuits of the signal coil will be connected one to the
cable and to the alternator or vibrator and the other to the overflow from
the artificial line; and the second coil 12 suitably arranged inserted as an out-
flow" between the vibrating tongue and the cable into which retransmission
takes place or preferably inserted at two suitable points near the beginning of
the artificial line which is employed in conjunction with the cable in the manner
above described. Or the same purpose may be effected by connecting these two
points of the artificial line to a separate circuit on the coil of the vibrator which
is described above as a substitute for the alternator required in carrying out this
invention. The outgoing current which flows into the artificial line passes, in
this case, through the vibrator and deflects the coil of the latter to the one side
or the other thus sending a strong current through the second coil in the direction
to make the contacts of the vibrating tongue with the local line battery stops
firmer. Or when it is not convenient to use the artificial line for this purpose
the vibrating tongue 13 may be connected through a self-inductance coil 25¹,
or its equivalent in artificial line, to the separate circuit of the vibrator as shown
in Figure 13. The amount of self-inductance of the coil 25' or retardation of the
artificial line, will be less than that of the coil 25 which is required for the
overflow circuit of Figure 13.
Sometimes the second coil may be dispensed with and the vibrating tongue
either loosely mounted and held by friction on the signal coil itself as shown
in Figure 15 or held on a separate body which is tied to the signal coil by fibres
as shown in Figures 13, 14 and 16.
It may sometimes be useful for the purpose of improving the contacts in
carrying out this invention to impart additional vibration either to the tongue 13
or to the stops 16¹, 171 themselves in a plane other than that of the said stops.
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. The combination, in the sending circuit of a telegraph system, of a trans-

page_text: mitter, a recorder coil in the battery circuit of such transmitter, a line battery,
and a loosely-mounted vibrating relay tongue or contact-making device.
2. The combination, in the sending circuit of a telegraph system, of a trans-
mitter, a recorder coil in the battery circuit of such transmitter, a line battery,
a loosely-mounted relay tongue or contact-making device and means serving to
constantly vibrate the latter.
3. The combination, in the sending circuit of a telegraph system, of a trans-
mitter, a recorder coil in the battery circuit of such transmitter, a line battery,
a loosely-mounted vibrating relay tongue or contact-making device and a con-
nection from the line battery through a recorder coil into the cable whereby the
contacts between the said contact-making device and the line battery are im-
proved.
4. A telegraphic receiving and translating arrangement comprising, in com-
bination, means in the receiving circuit adapted to be actuated by the cable
current, means serving to impart directive force both to the latter and to the
contact-making devices in connexion therewith, a loosely-mounted relay tongue
or contact-making device adapted to make contact with the terminals of a
retransmitting line battery, and means serving to constantly vibrate the said
contact-making device.
5. The combination, with the receiving and translating devices of a telegraphic
system, of means serving to impart constant vibration to the mechanism which
is actuated by the cable current whereby the contact-making device of the
retransmitting line battery is maintained in correct position relatively to the
part on which it is loosely mounted and to the terminals of the line battery
during signalling whatever may be the position of the signal coil.
6. A telegraphic receiving and translating arrangement comprising, in com-
bination, means in the receiving circuit adapted to be actuated by the cable
current, an attached tongue or contact-making device, one or more moving con-
tacts upon or against which the said tongue is adapted to oscillate thus creating
corresponding variations of current in the retransmitting circuit, and means
serving to impart constant vibration to some part of the organization.
7. The combination, with the receiving and translating devices of a tele-
graphic system, of an outflow" in connection with the circuit carrying the out-
going current from a line battery and a part of the mechanism which is either
directly or indirectly affected by the received cable current, for the purpose of
improving the character of the retransmitted signals.
65
8. The combination, with the receiving and translating devices of a tele-
graphic system, of an outflow" in connection with the circuit carrying the
outgoing current from a line battery, and curbing mechanism for the purpose of
improving the character of the retransmitted signals.
66
9. The combination, with the receiving and translating devices of a tele-
graphic system, of an overflow" in connection with the circuit carrying the
outgoing current from a line battery and a part of the mechanism which is
either directly or indirectly affected by the received cable current, for the pur-
pose of curbing the signal coil or the movements of some part of the mechanism
in the receiving circuit which actuates the contact-making device or the local
transmitters in connection therewith, substantially as described with reference to
Figures 3, 5, 6, 7, 8, 9, 12, 13, 14, 15, 16 and 17 of the accompanying drawings.
10. In a telegraphic receiving and translating arrangement the device for
improving the character of the retransmitted signals consisting of means in
the "overflow" connexion serving to automatically split up the outgoing cur-
rent into the correct number of separate signals substantially as set forth.
11. The combination at intermediate stations, with the receiving and trans-
lating devices of a telegraphic system, of two duplexed circuits in the manner
substantially as herein before described for the purpose of enabling transmission
to take place automatically between two sections of cable either simultaneously

page_text: or in alternate directions substantially as described with reference to Figure 12
of the accompanying drawings.
12. The telegraphic receiving and translating or transmitting arrangements
substantially as described and illustrated in the accompanying drawings.
Dated this 9th day of February 1900.
A. F. SPOONER,
323, High Holborn, London, Agent for the Applicant.