Improvements in Telegraphic Receiving and Translating Instruments.
Year: 1899

page_text: Date of Application, 9th Jan., 1899
PROVISIONAL SPECIFICATION.
Improvements in Telegraphic Receiving and Translating Instruments..
1, ALEXANDER MUIRHEAD, of Sherborne Lodge, Shortlands, in the County
of Kent, Telegraph Engineer, do hereby declare the nature of this invention
to be as follows:-
My invention has for its object to provide improved means for receiving and
translating telegraphic signals. Being more particularly applicable to submarine
cable circuits I will describe it in connection therewith, through it will be
understood that my invention, by obvious modifications, can be applied to
other electrical circuits.
Signals flowing from a submarine cable are generally received through the
well-known siphon recording instrument, and in the Specification of former
Letters Patent No. 20793 dated November 2, 1893 granted to me I have described
certain improvements relating to the suspension of the signal coil and to the
mode of giving directive force" to the same in such an instrument.
My present invention consists essentially in the utilization of that part of the
mechanism which imparts the requisite directive force to the signal coil in order
to effect electrical variations in a local or translation apparatus corresponding
to the movements of the signal coil.
The local or translating circuit contains two relays. These may be of the
Allan and Brown type; or preferably they may be of the form described in the
Specification of Letters Patent No. 10908 dated May 1, 1897; or they may be of
any other type suitable for translation on submarine cables, or other purpose for
which the organization is intended.
As will be understood, the actuation of one or other of these relays effects the
translation or re-transmission of the received signals. It has been attempted
before to utilize the signal coil of Kelvin siphon recorders to operate relay
tongues, but unsuccessfully owing to the fact that the necessary firmness of
contact for local circuit working was not attained and also by reason of the
difficulties in overcoming, without great loss of speed, the inertia of the extra
mechanism which the arrangement entailed and in maintaining the zero of the
combination.
My present invention can be attached to an existing siphon recorder. and the
received signals will then be recorded thereby, and, in addition, re-transmission
will be effected. If a record is not required at the intermediate station, manifestly
the ink siphon and its appurtenances can be dispensed with.
In carrying out my invention (and assuming that the recorder is taken intact)
the signal coil is connected to the aluminium cradle which carries the siphon by
two silk or other suitable fibres as described in my said prior specification first
hereinbefore referred to. At intermediate points between the signal coil and
the aluminium cradle the two fibres are, in some cases according to this invention,
fastened to the free end of two thin metallic strips (preferably of phosphor-
bronze) respectively. When the instrument is in adjustment for reception and

page_text: translation of signals these two metallic strips are normally resting against two
contact stops. The circuits of the two local relays which are required for trans-
lation are completed through the strips and the contact stops against which they
press.
Sometimes the two phosphor-bronze directive strips are coiled up into a
spiral or cylinder of small diameter as in Ayrton's magnifying spring measuring
instruments; one end of each spiral being fixed and the other end fastened by
silk fibres to the signal coil. Contact arms are attached to the spirals at their
free end and adjusted to rest against their respective contact stops when the
sigual coil is in its normal position.
In some cases the two phosphor-bronze strips (or one equivalent strip fixed
centrally and having both ends free) are fixed at one end to a plate on the
curved surface of which is mounted a series of contact rods in connexion with
a series of resistances forming part of a differential local relay circuit. The strips
are so fixed that they wrap or fold over the curved surface of the plate more or
less as the signal coil with which they are in connection at their free ends is
deflected on the passage of current from the cable or telegraphic circuit through
the conductor of the signal coil. The greater the amount of flexure of the
phosphor-bronze strips or springs the greater the number of resistances left in
circuit or short-circuited as the case may be; that is, the greater the variation
of resistance of the local relay circuits which include these resistances.
Instead of a series of separate resistances the surface of the curved plate on
which the phosphor-bronze strip folds and unfolds may be covered or coated
uniformly with a material of high specific resistance such as a mixture of
plumbago and kaolin or some suitable metallic sulphide such as cupric sulphide.
In either case a more uniform variation of the resistance of the local relay
or translation circuit is produced when the metallic strip folds and unfolds on
the curved surface of a uniform conducting material.
In some cases the two fibres which connect the signal coil to the phosphor-
bronze springs are continued and fastened to another coil suspended between the
poles of permanent magnets. This second coil is wound differentially to form
part of a Wheatstone bridge circuit composed of the series of resistances above
described in connection with the local or translation relays. Adjustable self-
inductance coils or other means of introducing a retarding effect to the establish-
ment of current in the circuits of the second coil that can be regulated are
inserted in the Wheatstone bridge arrangement.
In certain cases it is unnecessary to have a separate second coil; an additional
and separate circuit may be wound over the signal coil and connected up to the
local relay circuit as above described.
Or at intermediate cable stations where duplex working is established the said
second coil, on each side, may be inserted at a suitable point in the artificial line
circuit of the duplex apparatus of the cable on the other side. The current
which flows through this second coil from the translation battery in response
to the movement of the first or signal coil (that is the one which is in circuit
with the cable) of the opposite side assists the latter coil in overcoming the
inertia of the extra mechanism which is attached to it for the purpose of actuating
the translating apparatus according to this invention. In fact a curbing effect
is thus produced upon the signal coil and consequently an increase of the speed
of transmission is obtained.
Sometimes in carrying out this invention I introduce into the circuit of the
artificial line and in series with the second coil another recorder coil relay con-
structed in the same manner as the signal coil relay first hereinbefore described.
The local contacts which are actuated by this third relay are inserted between
those of the signal coil relay and the local translating apparatus; the function
of this third relay being to make the correct number of successive contacts of
the translating levers to correspond with any prolonged deflexion of the signal
coil that may be due to a too- rapid succession of contacts in one direction at the

page_text: distant station. This latter device can be applied to any kind of cable relay as
well as those which form the subject matter of this specification.
Or the same object may he attained without the third coil by inserting the
second coil in such manner as to operate on the local circuit of the signal coil
and not on the signal coil itself. In this case the second coil, is connected by
two fibres to two directive springs as described at the beginning of this specifica-
tion with reference to the signal coil and these springs with their respective
contact stops are inserted between the local contacts of the signal coil and the
translating apparatus which is actuated thereby. In this position relatively
to the signal coil the effect of the current from the artificial line through the
second coil will be to break the local circuit containing the translating apparatus
and put the cable to earth after the battery contact of the translating levers has
lasted the time required to retransmit a correct signal. Or the second coil
wound with two circuits and unattached to the signal coil may be joined up
directly to the translation apparatus, one circuit being included in the local
circuit of the signal coil and the other inserted in the artificial line as above
described.
Or the second coil, suspended by phosphor-bronze directive strips and wound
with two circuits, may be attached direct to the signal coil without the inter-
mediate directive strips and provided with.a pivoted local contact arm mounted
on the top of it and secured by friction thereto. This local contact arm in
this case is kept vibrating rapidly between the two local contact stops by means
of an alternating current through one circuit of the second coil; the other
circuit being joined up to the artificial line as above described.
In order to prevent adherence between the surfaces of the directive strips and
the body on which they fold and unfold, or between the directive strips and their
respective contacts in the arrangement first described, and at the same time to
secure firmer contact making between the surfaces involved I sometimes vibrate
the latter by means of mechanism similar to that described in the specification
of my first-mentioned prior patent for the purpose of imparting vibration to the
siphon in siphon recorders. Or sometimes vibration is imparted to the directive
strips by vibrating the signal coil to which they are tied. One way of vibrating
the signal coil for the purpose of this invention is to send intermittent charges or
discharges through it from a condenser placed in the make-and-break circuit
of an interrupter such as that described in the said specification or direct from
the interrupter battery without condenser. An alternating current from a
suitable dynamo passed through the signal coil will effect the same purpose.
Whenever vibration of the coil is resorted to in carrying out this invention the
contact stops of the directive springs are mounted upon a pivoted arm which is
secured by friction to a fixed standard. The constant vibration of the directive
springs against their stops serves to keep the latter in correct position relatively
to the springs, should the coil to which they are attached be deflected gradually
from its normal position by earth currents or other causes. This is an important
feature of this invention and is one which can be made use of in the local circuit
of any other form of cable relay.
DL1
Ja of Januave 1800
0 Improvements in Telegraphic Receiving and Translating Instruments.
I, ALEXANDER MUIRHEAD, of Sherborne Lodge, Shortlands, in the County
of Kent, Telegraph Engineer, do hereby declare the nature of this invention

page_text: and in what manner the same is to be performed, to be particularly described
and ascertained in and by the following statement:-
My invention has for its object to provide improved means for receiving and
translating telegraphic signals. Being more particularly applicable to submarine
cable circuits I will describe it in connection therewith, though it will be
understood that my invention, 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 my improvements added thereto sub-
stantially in the form indicated diagrammatically in Figure 8; and Figures
to 9 are diagrams illustrative of my invention."
The
Signals flowing from a submarine cable are generally received through the
well-known siphon recording instrument, and in the Specification of former Letters
Patent No 20793 dated November 2, 1893 granted to me I have described
certain improvements relating to the suspension of the signal coil and to the
made of giving directive force" to the same in such an. instrument.
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. Extending between the signal coil 1 and
the cradle 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 (see Figures 3 to 9) 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.
"
An important feature of my present invention consists in the utilization of
that part of the mechanism which imparts the requisite directive force to the
signal coil and its attachments in order to effect electrical variations in local
or translation apparatus corresponding to the movements of the signal coil.
The local or translating circuit contains two relays or local transmitters 6, 6
and a local battery 7. The relays may be of the Allan and Brown type; or
preferably they may be of the form described in the Specification of Letters
Patent No. 10908 dated May 1 1897; or they may be of any other type suitable
for translation on submarine cables, or other purpose for which the organisation
is intended.
.
As will be understood, the actuation of one or other of these relays effects
through the respective tongues 8, S and a retransmitting line battery 9 the trans-
lation or retransmission of the received signals. It has been attempted before to
utilize the signal coil of Kelvin siphon recorders to operate relay tongues, but
unsuccessfully owing to the fact that the necessary firmness of contact for local
circuit working was not attained and also by reason of the difficulties in over-
coming, without great loss of speed, the inertia of the extra mechanism which
the arrangement entailed and in maintaining the zero "of the combination
My present invention can be attached to an existing siphon recorder and the
received signals will then be recorded thereby, and, in addition, retransmission
will be effected. If a record is not required at the intermediate station, manifestly
the siphon and its appurtenances can be dispensed with and the suspension-
piece modified in the manner substantially as shown in Figure 2 or if a local
record of what is passing should be necessary, a more suitable arrangement is
to put a recorder in circuit at the distant end of each artificial line at the
intermediate or relay station.
In all the diagrams 10 represents the cable from which it is assumed for the
purpose of this description signals are about to be received and 11 the one into

page_text: which corresponding signals are to be retransmitted. 12 is the artificial line
or cable and 20, 20 (see Figure 6) the usual rheostats required in duplex working:
13, 13 represent the condensers which are usually placed between the cable and
the receiving or sending apparatus and E. E represent the earth connections.
It will be understood that by means of a switch the connections, in the case of
simplex working, may be changed over so that the cable 11 is connected to the
coil 1 and the cable 10 to one of the tongues S, 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 duplicated as illustrated in
Figure 6 where a complete duplex installation at an intermediate station is
shown on the well-known "Muirhead" plan. When both 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 between the two sections
of cable automatically whether on "duplex" or simplex.'
"
In carrying out my invention and referring first to Figure (and assuming
that the recorder is taken intact) the signal coil 1 is connected to the cradle
(see Figure 1) by the two silk or other suitable fibres 5, 5 as described in my
said prior specification first hereinbefore referred to. At intermediate points
between the signal coil and the aluminium cradle the two fibres are, in some
cases according to this invention fastened to the free end of two thin metallic
strips 14. 14 (preferably of phosphor-bronze) respectively. When the instrument
is in adjustment for reception and translation of signals these two metallic
strips 14. 14 are normally resting against two contact stops 15, 15. The contact
stops 15, 15 are carried by an arm 27 which is pivotally mounted and supported
by friction on a standard for an object to be hereinafter described.
The circuits of the two local relays 6, 6 which are required for translation
are completed through the strips 14, 14 and the contact stops 15, 15.
In some cases the two phosphor-bronze strips (or one equivalent strip fixed
centrally and having both ends free) are fixed at one end to a plate on the
surface of which is mounted a series of contact rods in connection with a series
of resistances forming part of a differential local relay circuit. The strips are
so fixed that they wrap or fold over the curved surface of a plate more or less
as the signal coil with which they are in connection at their free ends is deflected
on the passage of current from the cable or telegraphic circuit through the
conductor of the signal coil. The greater the amount of flexure of the phosphor-
bronze strips or springs the greater the number of resistances left in circuit or
short-circuited as the case may be; that is, the greater the variation of resistance
of the local relay circuits which include these resistances.
Instead of a series of separate resistances the surface of a plate 16 (see
Figures 4 and 5) on which the phosphor-bronze strip 14 folds and unfolds may
be covered or coated uniformly with a material of high specific resistance such
as a mixture of plumbago and kaolin or some other suitable material.
In either case a more uniform variation of the resistance of the local relay or
translation circuit is produced when the metallic strip folds and unfolds on the
surface of a uniform conducting material.
In connexion with the arrangements described with reference to Figures 4
and 5, a second coil 17 is employed wound either singly as shown in Figure 4
or differentially as shown in Figure 5 to form part of a Wheatstone bridge circuit
composed of the series of resistances above described in connection with the local
or translation relays.
In certain cases it is unnecessary to have a separate second coil; an additional
and separate circuit may be wound over the signal coil and connected up to
the local relay circuit as above described.
At intermediate cable stations where duplex working is established, as illus-
trated by Figure 6, the said second coil, 17 (or optionally a separate circuit on
the coil 1) on each side, may be inserted at a suitable point in the artificial line
circuit of the duplex apparatus of the cable on the other side. The current

page_text: which flows out of the artificial line and through this connection 18 (and which
I have called an "overflow" circuit) from the translation battery 9 in response
to the movement of the first or signal coil 1 (that is the one which is in circuit
with the cable) of the opposite side assists the latter coil in overcoming the
inertia of the extra mechanism which is attached to it for the purpose of
actuating the translating apparatus according to this invention. In fact a
curbing effect is thus produced upon the signal coil and consequently an
increase of the speed of retransmission is obtained. The passage of the overflow
current from the artificial line through the signal or second coil secures the
correct number of successive contacts of the relay tongues 8, 8 when a prolonged
deflection of the signal coil takes place in one or other direction owing to rapid
signalling. The overflow device can be applied to any kind of cable relay as
well as to those which form the subject matter of this specification.
Or the same object may be attained by inserting a separate coil 21 (see
Figure 7) in such manner as to operate on the local circuit of the signal coil
and not on the signal coil itself. The separate coil is connected by two fibres
to two directive strips as herein before described with reference to the signal
coil and these springs with their respective contact stops are inserted between
the local contacts of the signal coil and the translating apparatus which is
actuated thereby. In this position relatively to the signal coil the effect of the
current from the artificial line through the separate coil will be to break the
local circuit containing the translating apparatus and put the cable to earth after
the battery contact of the relay tongues 8, 8 has lasted the time required to
retransmit a correct signal.
In some cases the second coil 17 may be mechanically attached, either with
or without the intermediate directive strips 14, to the signal coil 1 (see Figures 2,
6 and 8).
There may be supported on the second coil 17 and independently mounted
either on the same axis, or on an independent one, a well-insulated tongue 22
whose freedom of movement relatively to the said coil is regulated by a pressure-
spring 28 and screw-head 24 or like device.
The tongue 22 is, according to this invention, kept in a state of constant tremor
or vibration between the two local contact stops 25, 25 by means of an alternator A
connected up to one circuit of the second coil 17, the other circuit forming part
of the overflow 18 as above described. The constant vibration of the tongue 22
keeps the latter always in the zero position relatively to the contact stops 25, 25.
In Figure 9 is illustrated an arrangement in which the second coil 17 is
dispensed with and a separate circuit wound on the signal coil 1 for the "
How circuit 18 the vibrator or alternator A, being connected up to the signal
coil itself and the vibrating tongue 22 is mounted in a manner similar to that
described with reference to Figures 2 and 8 on a bar 26 to which the signal coil
is attached by the two fibres 5, 5.
over-
Whenever vibration of the signal or second coil is resorted to in carrying
out this invention the contacts 15 in Figures 3, 5, 6 and 7 of the directive strips
are mounted upon a pivoted arm 27 which is secured by friction (in a manner
similar to that described with reference to the tongue 22) to a fixed standard.
The constant vibration of the directive strips against their contacts serves to
keep the latter in correct position relatively to the strips, should the coil to
which they are attached he deflected gradually from its normal position by
earth currents or other causes.
This application of vibration to contact-making devices is a third important
feature of this invention and is one which can be made use of in the local circuit
of any other form of cable relay.
The vibration required for the purpose of this invention may be obtained by
any suitable means. For example mechanism similar to that described in the
specification of my first mentioned prior patent for the purpose of imparting
vibration to the siphon in siphon recorders may be employed, Or sometimes

page_text: vibration is imparted to the directive strips or to the bar carrying the contacts
against which the strips press by vibrating the signal coil to which they are tied.
One way of vibrating the signal coil for the purpose of this invention is to
send intermittent charges or discharges through it from a condenser placed in
the make-and-break circuit of an interrupter such as that described in the
specification or direct from the interrupter battery without condenser. An alter-
nating current from a suitable alternating dynamo A passed through the signal
coil or other suitable coil in the system will effect the same purpose.
Adjustable self-inductance coils 19 or other means of introducing a retarding
effect to the establishment of current in the local circuits of the arrangements
may be inserted for the purpose of toning down or eliminating altogether the
effect of any rapid vibratory, current that may be produced in the circuit con-
taining the local transmitters in carrying out this invention.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is:-
1. In a telegraphic receiving and translating system, means whereby that part
of the mechanism which imparts directive force to the signal coil and its attach-
ments is utilized to effect the electrical variations in a local or translation apparatus
substantially as set forth.
2. In a telegraphic receiving and translating system, the method of imparting
a constant tremor or vibration to the contact-making part of the mechanism of
the local or translation apparatus or some part in connexion therewith in order
to preserve its zero position relatively to the points against which it vibrates.
3. In a telegraphic receiving and translating system, the combination, with
a frictionally mounted part of the contact-making mechanism of the local or
translation apparatus, of means serving to impart constant tremor or vibration
thereto.
"
4. The combination, with the receiving and translating devices of a tele-
graphic system, of an overflow connection between the circuit carrying the
outgoing current from a line battery and that part of the mechanism which is
actuated by the received cable current, for the purpose of curbing the part of
the mechanism which actuates the contact-making device.
5. The combination, at intermediate stations, with the receiving and translating
devices of a telegraphic system of two duplexed circuits in the manner sub-
stantially as herein before described for the purpose of enabling transmission to
take place automatically between two sections of cable either simultaneously or
in alternate directions.
6. The telegraphic receiving and translating arrangements substantially as
described and illustrated in the accompanying drawings.
Yuzha 1200
A. F. SPOONER,
323, High Holborn, London, Agent for the Applicant.
A. F. SPOONER,
323, High Holborn, London, Agent for the Applicant.