IMPROVEMENTS IN ELECTRIC TELEGRAPHS
Year: 1873

page_text: LETTERS PATENT to George Kitt Winter, F.R.A.S., Telegraph Engi-
neer of the Madras Railway of Arconum, in the Presidency of
Madras, British India, at present residing at No. 2, Wilton Villas,
Shepherd's Bush, in the County of Middlesex, for the Invention
of "IMPROVEMENTS IN ELECTRIC TELEGRAPHS."
Sealed the 20th May 1873, and dated the 1st March 1873.
PROVISIONAL SPECIFICATION left by the said George Kift Winter
at the Office of the Commissioners of Patents, with his Petition, on the
1st March 1878.
I, GEORGE KIFT WINTER, F.R.A.S., Telegraph Engineer of the Madras
Railway of Arconum, in the Presidency of Madras, British India, at
present residing at No. 2, Wilton Villas, Shepherd's Bush, in the County
of Middlesex, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN ELECTRIC TELEGRAPHS," to be as follows:-
KOSAL:- I-nantian owe the improvement of duplex telegraphy

page_text: 1st. I apply the principle of opposing batteries to duplex working.
A battery is joined up at each station with the similar poles to earth.
The coils of the instrument are inserted in each case between the battery
and the line. At a certain point in the coil a key is connected; the
other terminal of the key is put to earth. The exact adjustment of the
arrangement is made by means of resistance coils or by other convenient
means.
Or according to another arrangement a battery is as before joined up
at each station with similar poles to earth, and also as before the instru.
ment coils are in each case connected up between the battery and the line.
The coil in this case is shunted at each station by a slide resistance, one
terminal of the key is joined to the movable contact of the slide resistance,
the other terminal of the key is joined to earth.
1
2nd. In duplex telegraphy I initiate in the local branch or circuit, or
counteract in the main circuit the action of the static induction of the
main line or cable by electro-magnetic induction or by an induction
battery.
3rd. In applying duplex telegraphy to cables I put the receiving
instrument A between two condensers, one connected with the cable and
the other with a local circuit; or B, in the secondary circuit of one or
more induction coils whose primary wire or wires are arranged for duplex
telegraphy; or C, in the common cross circuit of two induction bridges
arranged for duplex telegraphy. In each of these cases a modification
may be made by winding the instrument coil differentially and con-
necting each coil with respectively each of the two condensers, or each
of two secondary coils, or each of the two cross circuits of the induction
bridges.
4th. In duplex telegraphy in cases where two sources of electricity
are used in place of splitting a single current it is preferable generally
to use currents generated by induction coils, or by armatures covered
with wire moving in a magnetic field, and in such cases I cut off more
or less of the reverse current sent into the cable, but let the reverse
current in the local circuit have its full effect. (This may be effected
with induction coils or armatures) as follows:-The coil sending
currents into the cable may have a copper wire or band wound next to
the core, which is automatically left open while the current is sent, but

page_text: closed immediately afterwards so as to absorb the reverse current or a
portion of it.
The automatic arrangement may be mechanical in the key or electrical
by means of an electro-magnet connected with the primary circuit, with
The
an armature taking a short time to be attached and liberated.
armature making contact cn attraction will close the absorbing circuit
with batteries; it may be effected automatically with the key.
•
5th. I use a galvanometer with the above arrangements, or generally
for the measurement or indication of feeble currents made as follows :—
A portion of the axle connected with the needle or needles is bent into
three sides of a squarc.
The interior of the galvanometer is then made
into a kind of magic lantern by means of cylindrical lenses so as only to
spread the light passing through the interior into a horizontal band. The
image of the vertical bar of the square will then be thrown on the screen
and will move horizontally with the motions of the needle.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said George Kift Winter in the Great Seal Patent
Office on the 1st September 1873.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, GEORGE
KIFT WINTER, F.R.A.S., Telegraph Engineer of the Madras Railway of
Arconum, in the Presidency of Madras, British India, at present residing
at No. 2, Wilton Villas, Shepherd's Bush, in the County of Middlesex,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the First day of March, in the year of our
Lord One thousand eight hundred and seventy-three, in the thirty-sixth
year of Her reign, did, for Herself, Her heirs and successors, give and
grant unto me, the said George Kift Winter, Her special license that I,
the said George Kift Winter, my executors, administrators, and assigns,
or such others as I, the said George Kift Winter, my executors, adminis-
trators, 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 ELECTRIC TELEGRAPHS,"

page_text: upon the condition (amongst others) that I, the said George Kift Winter,
my executors or administrators, by un 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 George Kift Winter, do hereby declare
the nature of the said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the
following statement thereof, that is to say :-
This Invention has for its objects the improvement of duplex telegraphy,
and its application to submarine cables.
For duplex working I make use of opposing batteries, whereby the
battery power required is little more than that required for single working,
and the adjustment for compensating changes in the insulation of the line
is simplified. At each end of the line the battery is permanently inserted
with the same pole to earth in each case. The receiving instrument is
inserted between the battery and the line at each end. At a point in the
coil of the instrument much nearer to the battery end than the line end
the wire is connected with one terminal of a key, the other terminal being
connected with earth. The effect of depressing the lever of the key is to
connect together these two terminals. A resistance coil may, if necessary,
be inserted between the battery and the instrument.
Figure 1 shews the general arrangement. A and B represent the two
terminal stations. I is the line between them. At each station i is the
receiving instrument; is the key; b, the battery; e, the earth
connection; and r, a resistance coil. Suppose of the wire of the
instrument is between k and r, and between A and 2; let the
resistance be that of the line, and let us first suppose the insulation
of the line to be perfect. If now the key at A is depressed, the battery
at A is on short circuit through the resistance and of the instrument.
The current from the battery at B flows through the whole of the instru-
ment at B, the whole of the line wire, and 1% of the instrument at A.
Its action on the instrument at A is antagonistic to that of the battery,
acting locally at that station, and as it has to go through about 9 times
the resistance it has only about the strength of the current of the

page_text: battery on short circuit at A, but as it has 9 times as many convolutions
of the instrument wire to pass through the actions are just balanced, and
the instrument at A is unaffected. At B however it is evident that the
whole of the battery acts through the whole of the coil of the instrument,
and produces a signal accordingly, which is only slightly weakened by
the insertion of the resistance r. When B coinmunicates with A the
matters are simply reversed.
When both keys are depressed at once the battery at each station
acts locally, and the action on each instrument is only about less
than the action of the whole of the battery, when, after traversing the
line, it acts upon the whole of the coil of the instrument as in single
sending.
Now, suppose the insulation to become imperfect, there will be a
slight current from each battery running through the instrument to line,
and tending to produce a signal. All we have to do to remedy this is to
give the instrument a bias against making a signal equal and opposite to
the effect produced by the leakage current. With most instruments,
especially with the polarized relays now almost universally employed,
this is done by the ordinary adjustment of the instrument with which
operators are already familiar.
Another but less perfect arrangement is shewn in Figure 2. In this
arrangement the key, instead of being connected to a point in the wire
in the interior of the instrument coil, is joined to a point in a resistance 8
acting as a shunt on the receiving instrument much nearer to the
battery end of the shunt than the line end. A suitable proportion
between the resistance aud the instrument coils is, say 4 or 5 to 1.
The point where the key is connected may, if required, be made
adjustable by means of a sliding contact.
Both the above arrangements can be applied to intermediate instru-.
ments very simply, unless the instrument is a polarized relay or
analogous apparatus, by making the point where the key is connected
nearer to the middle of the instrument coil in the first arrangement, and
of the shunt in the second method. The intermediate stations can then
communicate with each other or with the terminal stations in duplex,
and without batteries. The arrangements of a circuit with an inter-
mediate station under the two systems are shown in Figures 1 and 2ª.
If, however, polarized relays are employed the following arrangement

page_text: may be adopted at intermediate stations:-The relay may have two
tongues or armatures, one acted upon when the current is in one
direction, and the other when the current is in the other direction
through the relay. This arrangement is shown in Figures 1 and 2.
t, t, are the tongues which close the circuit in which the local instrument
and battery m and B are contained. Or if it is considered desirable not
to have relays of more than one pattern there may be two relays and
two keys, as shown in Figures 1° and 2°. The relay marked I in each
Figure is connected so as to work when the direction of the current is
that which would be caused by the action of the battery at B, and the
relay marked 1 is connected up so as to work when the direction of the
current is that which would be caused by the action of the battery at A.
The key K is used in communicating with A, and the key K' is used in
communicating with B. The same letters and description are applicable
to both Figures. Or in Figure 2 a continuous shunt may be used to the
two instruments, and then only one key will be necessary.
I also, according to my Invention, when requisite in duplex working
with opposed batteries, compensate the static induction of the line.
The effect of the static induction of the line in the opposed battery
system is as follows:-When both keys are in their normal position tho
potential of the whole line is raised or lowered by the opposing batteries
above or below that of the earth, and the line will in consequence hold a
charge which will depend for its quantity upon the inductive capacity of
the line. When either of the keys is depressed, the potential of the
circuit at that point will be made the same as that of the earth, and half
the charge of the line will flow out through the line coil of the in-
strument. When the key is raised the battery will immediately charge
the the line to its original potential, and this charge will pass through the
coils of the instrument. In the second of the two systems (see Figure 2)
the effect of the charge and discharge will be lessened by part being
carried off by the shunt. It is evident therefore that at each depression
of the key we have a strong instantaneous current flowing in one
direction through the line coils of the instrument, whereas when the key
is raised there is another instantaneous current flowing in the opposite
direction through the whole coil. To counteract this when working
according to the first method, shewn at Figure 1, I causo the key to
make two contacts simultaneously, one connecting the point in the
instrument coil to which the key is attached with earth, and the other

page_text: completing the primary circuit of an induction coil, the secondary wire
of which is connected either with an independent coil of the relay as
shewn in Figure 8, or (although less advantageously) with the two ends
of the relay coil, as shewn in Figure 4. When the key is depressed the
primary circuit is completed, and a momentary induced current is
generated in the secondary coil, which acts upon the relay in the reverse
direction to that of the discharge. When the key is raised the primary
circuit is broken, and a momentary current is induced which acts upon
the relay in the reverse direction to that of the charge. The exact ad-
justment of these compensating currents is accomplished either by
drawing the iron core in and out of the coil, or by covering more or less
of the iron core by a non-magnetic conducting cylinder until induced
currents of the required strength are obtained. Or I place a coil of wire
wound on an iron core between the instrument and the line, and a shunt
of common wire between the line end of the magnet and the key, as shewn
in Figure 5.
In the second method of opposed batteries the compensation for static
induction of the line is effected as shewn in Figure 6, in which the
secondary wire of the induction coil forms part of the working shunt
preferably on the line side. Or 1 put a coil of wire wound on an iron
core between the instrument and the shunt, on either, as in Figure 7. Or
I wind the shunt on the battery side of the key on an iron core, as shewn
in Figure 8.
In the application of duplex telegraphy to cables, we have far more
powerful inductive effects to contend with than on land lines, and before
explaining the methods by which I propose to counteract these effects,
it will be well to describe them, and for simplicity we will suppose the
system of telegraphing to be as follows:-Sometimes a copper current is
put to line, and sometimes a zinc current is put to line, but in either case
the line is immediately afterwards put to earth. Combinations of the two
signals thus obtained form the alphabet as in the single needle telegraph.
Sometimes a condenser is inserted between the source and the cable.
Let us suppose that the sending current passes through the coils of the
receiving instrument, and that there is no compensation at all. The
action of the static induction of the cable is, at the first moment to make
the resistance of the cable appear very small, and hence a very powerful
current enters the cable through the instrument. When the cable is put
to earth there is a discharge from the cable,
which if there be no

page_text: condenser in the circuit is less than the flow in. or charge, but the
difference between the two will depend upon the inductive capacity of
the cable together with the length and resistance of the conductor.
With cables of a moderate length the discharge is nearly as instan-
taneous as the charge, but in long cables the discharge is lengthened,
being strong at first, and then gradually diminishing less or more rapidly
according to the inductive capacity of the cable, and tho length and
resistance of the conductor. The effects of the static induction of the
cable may be largely diminished by the insertion of a condenser at the
sending end, so as to prevent the source being applied directly to tho
cable, and in this case the effects above described will be modified.
Both the charge and discharge will be much less than when the source
is applied direct to the cable, but they will be equal to each other in
quantity, though the discharge will as before be less instantaneous than
the charge.
It will be well here to explain the two general methods by which apart
from the action of induction, the action of the sending current on the
receiving instrument is counteracted by a current in a local or compensating
circuit, so as to leave the receiving instrument unaffected and free to indi-
cate the received signals.
1st. The instrument is wound differentially, and one current is allowed
to go through one coil into the line and another or compensating current
is sent through the other coil into a local circuit; matters being so arrange 1
that the effect of these two currents shall balance each other.
2ndly. One current is made to pass by one end of the instrument into
the line, and another or compensating current is passed by the other end
of the instrument into a local circuit; matters being so arranged that the
potential of the two ends of the instrument, as modified by these currents,
shall always be equal. The term local or compensating circuit will now
be understood.
The effect of the first apparent small resistance of the cable, and conse-
quently powerful initial current, may be counteracted by making the
compensatingcurrent correspondingly powerful. And I propose to counteract
the lengthened discharge in one of the two following ways, or in combina-
tion of them:-

page_text: local circuit or forming a shunt on the line coil of the instrument. Of
curse resistance may be added in either case.
2ndly. By the use of two separate sources; one for producing the
signalling current, and the other producing the compensating current;
the source acting in the local or compensating circuit being made to
produce currents which are similar to and able to counteract not only
the current proper of the sending source but also the current caused by
the discharge from the cable.
Two examples of the first method are shewn in Figures 9 and 10, in
which a condenser is inserted between the battery or source and the
cable. The source used consists of two equal batteries, so connected
that when not in use they oppose each other, and hence produce no
current. Each battery is connected with a reversing key by which its
poles may be reversed and so made to act in the same sense as the other.
The reversing key may be similar to Varley's wheel key, and it should be
BO arranged as to cause no disconnection in any part of its action. The
other parts of the arrangement are sufficiently explained by the Diagrams
themselves. In each of these Figures two induction batteries are shewn,
but in either case one only may be employed and then I prefer to retain
that in the local circuit.
Two examples of the second method are shewn in Figures 11 and 12,
in which the sources are induction coils worked by a common primary
current; but the primary wire of the coil producing the compensating
current is provided with a shunt consisting of an induction battery.
In these arrangements a condenser is used in the local circuit as well as
in the line circuit.
In place of using condensers as in the above methods we may use the
secondary current from one or more induction coils for working the
receiving instrument and so connect the apparatus that while sending a
compensating current shall either prevent at the sending station the
formation of induced currents by the sending currents or else shall
produce induced currents which shall counteract on the receiving
instrument at the sending station, those produced by the currents passing
from the sending apparatus into the cable. This may be effected in
either of the ways shown in Figures 13, 14, 15, or 16.
In Figure 13 the receiving instrument is included in a secondary
circuit of an induction coil, the primary wire of which is traversed by

page_text: the cable currents; and in 'sending, the ends of the primary wires are
connected with two sources which are in equilibrium, and hence do not
give rise to a difference of potential between them.
1
In Figure 14 the induction coil has two primary wires, one of which
is traversed by the cable currents and the other forms part of a local
circuit.
•
In Figure 15 the instrument is connected with the secondary wires of
two induction coils, the cable currents traverse one of the primary wires,
and the other primary wire forms part of a local or compensating
circuit.
'
In Figure 16 the two secondary wires are not connected together as
in Figure 16, but the instrument is wound differentially, and each
secondary wire acts upon one of the wires of the instrument.
According to a third arrangement I use what I call an induction
bridge for receiving the currents from the cable, and the receiving 1
instrument is in this case worked by induced currents generated in the
wire of the induction bridge. Suppose A and B, Figure 17, to be
respectively the first and second branches of a Wheatstone's bridge on
the left hand side, and C, and D respectively the first and second
branches of the right hand side, and let theso branches be so adjusted
A B
that
I
and therefore that balance is produced. Let us wind the
D
이야
C
wires composing B and C simultaneously on a soft iron ród or bundle of
iron wires. If a receiving instrument be put into the cross circuit,
namely, between the points where A is joined to B, and C is joined
to D, and the bridge so formed be inserted at the receiving end of a 2
cable, then so long as a steady current is flowing there will be no action
on the receiving instrument, but when any change takes place in the
current passing through the bridge a current will be produced in the
receiving apparatus which will be in one direction during the increase,
and in the reverse direction during the decrease of the current passing 3
through the bridge. Earth currents change too slowly to produce any
observable effect in the receiving apparatus, while signals from the
distant station are sharp and well defined.
}
The instrument in the simple form above described is suitable for
50
Ti thin innument Goa dunlay waskia L Q

page_text: arrange it as shewn in Figure 18, and by winding over the iron core a
third wire forming part of a local circuit and conveying currents acting on
the iron core in the opposite sense to the action of the currents arising
from the sending. I prevent the magnetization of the iron and consequent
production of induced currents by them. When any of the above arrange-
ments of induction coils or bridges are used in place of a condenser, it is
of the greatest consequence that the resistance of the apparatus should be
kept constant, and though this is to a certain extent secured by the
arrangement of the batteries shown in Figures 9 and 10, yet I prefer to
use currents caused by magneto-electric induction in coils of wire,
permanently connected with the circuit, as shewn in Figures 11 and 12.
And here I would explain that it is quite possible by a suitable arrange-
ment of the inducing battery and primary and secondary wires, &c.,
to produce induced currents, having as small an electro motive force
as the batteries in common use on cables at the present time, and
consequently no more dangerous to the insulation. Nevertheless the
opposed battery arrangement as shewn in Figures 9 and 10) may bo
used if it is thought desirable. Figure 19 is an example. The instrument
and its induction coils are similar to that already described in respect to
Figure 14.
On short cables when induction coils are used as the source, and the
condenser not inserted between the source and the cable, it is sometimes
sufficient merely to cut off more or less of the reverse current from passing
into the cable, but allowing the reverse current to have its full effect in
the local circuit. The extra reverse current in the local circuit will
counteract the return current from the cable. This may be done in various
ways such as the following:-We may have a band or wire wound on the
coil of the induction coil which furnishes currents to the cable between
the secondary coil and the iron core. The ends of the band or wire shall
be disconnected or left open while the inducing current is being sent, but
closed immediately afterwards so as to absorb the reverse current or a
portion of it. The amount absorbed may be regulated by the insertion or
withdrawal of resistance. The closing of the absorbing circuit may be
accomplished by a mechanical arrangement of the key such as the
following: At the end of the key lever there is a spring which as it
rises and falls during the manipulation presses against a stud, and it
bears against one side of it whilst rising, and against the other side whilst
falling.

page_text: The form of the stud and the route of the spring are shown in Figure 20.
The dotted line shewing the route of the spring when the key is depressed
and whilst the spring is rising, and the unbroken line shewing the route
of the spring whilst it is falling. One side of the stud (that shewn white
in the Figure) is an insulator, and the other a conductor connected with
one end of the absorbing coil, the spring is connected with the other.
The spring is insulated from the rest of the key. Where the cable is short
enough for the discharge to be practically instantaneous, the above is
sufficient compensation for induction, but in longer cables we have also to
longthen the reverse current in the local circuit, as before explained. An
example is shewn in Figure 21.
Besides the methods we have described of causing the action of the
compensating source to be different from the signalling source, and hence
producing currents which counteract not only the action of the sending
current itself but also the discharge from the cable, there are many others,
for instance, instead of using an induction battery as a shunt on the com-
pensating coil, or in addition thereto we may use the arrangement shewn
in Figure 23, in which the prolonged reversal is obtained by the slow
withdrawal of one of two permanent magnets from the core of the
compensating coil.
c, c, is the core of the compensating coil; p, p, is the primary wire; i, i,
is the secondary wire; n, s, and n, s, are the two magnets suspended from
two pivots h, h; 5, 8, are two springs against which the lower ends of the
magnets are pulled by two strings passing over two pulleys and support-
ing two floats f. f. The pulleys revolve on axles carrying fans, and
are arranged to run independently of the axles in one direction only,
namely, that in which the strings would turn them when the magnets are
being attracted to the core, a ratchet or analogous arrangement can be used
for this purpose; a, a, are two stops which prevent the magnets approach-
ing too close to the core.
Another method is shown in Figures 23 and 24. a, b, c, d, Figure
23, are four branches of a bridge, and e is a battery permanently
connected, p is the primary wire of an induction coil, and s is the
secondary wire forming part of the compensating circuit; each of the
branches, a and b, are composed of a fine platinum or other un-
oxidizable metal wire wound on an ebonite or other non-conducting
cylinder. One of the branches is shewn in Figure 24. The cylinder is

page_text: suspended from a beam B. The beam is supported on a fulcrum, and
has a counterpoise suspended in a vessel of water or other liquid. The
cylinder is also suspended in a vessel of conducting liquid, say water,
and the water forms one end of the circuit of the branch, and the beam
which is connected electrically with the upper end of the platinum
helix forms the other. Attached to the beam is an armature, and
underneath it is an electro-magnet, the coil of which is traversed by the
current from one of the keys. Whenever the current passes through
the coil the armature is attracted, and the ebonite cylinder, which is
weighted, sinks into the water and the resistance of the branch is
lessened. When the current ceases the cylinder rises again, but there
are fans attached to the cylinder which collapse while the cylinder sinks,
but open and retard its rising. Let us suppose that the risistance of the
branch a is being lessened in this way by the depression of one of the
keys, and let us suppose the arrows, Figure 23, to represent the direction
of the current constantly passing through the bridge. When a is
diminished there will be a current in one direction, generated in p, and
consequently an induced current in s. When a again increases balance
will gradually be restored and the current through p will diminish, and
this will cause an induced current in the opposite sense in s. This
second induced current may be adjusted, as to length, &c., by the weight
of the counterpoise, the size of the fans on the cylinder, &c. There
are many other ways of applying the same method.
Having thus described the nature of my said Invention, and the
manner of performing the same, I would have it understood that,—
1. I claim the method of telegraphing simultaneously in opposite
directions through one line wire by the use of opposed batteries,
substantially as described.
2. I also claim in connection with the application of opposed batteries
in duplex telegraphy the means of compensating the static induction of
the line by the use of an induction coil, whose primary circuit is closed
and opened simultaneously with the making and breaking contact
between the line and earth, and whose secondary coil is connected either
with a separate coil in the instrument or with the wire of the instrument
itself.
3. I also claim in connection with duplex telegraphy through cable
lines the employment of induction batteries to compensate the statio
induction of the line, substantially as described.

page_text: 4. I also claim in connection with duplex telegraphy through cable
lines the arrangement of the receiving instruments with a condenser on
each side of them, substantially as described.
5. I also claim in connection with duplex telegraphy through cable
lines the use of two sources producing curronts made to differ from ono
another by the amount necessary to compensate for the static induction
of the line, substantially as described.
6. I also claim in connection with duplex telegraphy through cable
lines the connection of the receiving instrument with the secondary
wire or wires of an induction coil or coils, the primary wire or wires
being so connected with the source or sources (when a signal is given)
that two primary currents neutralize each other as respects the action of
the receiving instrument, substantially as described.
7. I also claim in connection with duplex telegraphy through cable
lines placing the receiving instrument in an "induction bridge"
forming part of the main circuit, and winding the core of this induction
bridge with a compensating coil forming part of a local circuit
subatantially as described.
8. I also claim the arrangement of apparatus for duplex telegraphy,
substantially as indicated by the Drawings hereunto annexed.
In witness whereof, I, the said George Kift Winter, have here-
unto set my hand and seal, this Eleventh day of June, in
the year of our Lord One thousand eight hundred and seventy-
three.