Improvements in or relating to Electric Telegraphy.
Year: 1898

page_text: Improvements in or relating to Electric Telegraphy.
I, PIERRE PICARD, of 95, Boulevard Beaumarchais, Paris, in the Republic of
France, Engineer, do hereby declare the nature of this invention to be as follows:-
Experts know how many difficulties are met when it is proposed either to
increase the efficiency of submarine cables or to use for them a synchronous
apparatus, such, for instance, as Hughes', whilst as regards Baudot's apparatus,
nobody would think of using it for cables of a considerable length, even inferior
to that of the Franco-Algerian cables.
The failures in this respect depend on the incompatibility of the laws of electric
propagation in cables of great electro-static capacity with the necessary irregu-
larity of signals to be transmitted.
In order that a current sent from a station may produce its effect at the distant
end of a cable in a neutral state, a certain perfectly definite time is required, and
the successive signals would be transmitted quite correctly, if the cable were
always brought back into its original condition. This result is approached if
cach current sent say a positive is immediately followed by a neutralising current
say a negative current.
But the last residual negative charge is not always constant and depends on
the time which elapses before the next positive current is sent. But these time-
intervals being extremely variable in the Hughes apparatus, the successive cur-
rents sent have their nature altered and at their arrival at the other end, their
effects do not take place at sufficiently precise periods. If, however, the variations
remain within the limits of error of the instrument, the transmission is, of course,
still possible, but requires considerable correcting.
The feature which more particularly distinguishes the system according to the
present invention from all others hitherto used or tried. especially as regards the
Synchronous-apparatus, is the absolute abandonment of the idea or practice of
bringing the cable back into a neutral condition each time after sending a working
current. In this new system the charge of the cable does not vary between two
successive sendings of the current, and as the working currents in this method
are always sent alternately, they always find the cable in a symmetrically similar
state. In other words, a positive current finds the cable with a determined nega-
tive charge, a negative current finds it with a positive charge equal to the previous
negative one and so on.
Attempts have also been made to devise a system of signals enabling the
greatest possible speed to be attained. The utmost limit reached was the trans-
mission of signals of equal duration and combined as to signs without regard to
the alternation. These are the signals of the syphon recorder.
The method according to the present invention is based on the absolute alterna-
tion of signs combined with the equality of charges, the intervals between them
not being taken into consideration.
This method is applicable to all kinds of apparatus.

page_text: influence which could modify its electric state in any manner whatever, between
the alternating charges which succeed one another at unequal intervals. It is
therefore necessary to avoid earthing it during the variable periods. But the
cable may be isolated say between each time that a current is sent so that in this
way anything that could irregularly alter the state of the line at the sending
station will be avoided as far as possible.
The transmission of equal charges is effected either by direct currents from a
battery or by discharges of the condensers of the transmitting station or by the
combination of the two for equal periods in each case.
On sufficiently short lines or cables the transmission could sometimes be effected
by means of induction-currents. But in this case the currents succeeding one
another at unequal intervals find the line in different states and the nature of the
signals is altered-if the line is too long owing to the conductor not being isolated
between each sending of the current.
Although in theory the line is isolated after each sending of a current (the
alternation being absolute and the contacts of equal duration) it is obvious that
according to the nature of the cables, this isolation can be replaced by a connection
to earth for a determined period succeeded by an isolation or even by connecting
it with one or several conductors charged to a determined potential. The right
is therefore reserved of using all possible combinations of batteries, earth and con-
densers with or without isolation at the transmitting station, according to cir-
cumstances.
Finally the currents can be also sent by placing the source in shunt on any
point of the line terminated at both ends by receivers and provided with condensers
In this case the transmitting and the receiving are the same.
The contacts producing the current being of equal duration, the charges pro-
duced will be equal. With apparatus in which the currents have to produce at
the receiver signals of unequal duration, such for instance, as Morse, Wheatstone,
Baudot, etc., it is preferable to make the position of the armature of the receiving
relay agree with the sign of the currents sent.
Hughes' apparatus is altogether different and is always worked by currents of
equal duration but divided by unequal intervals.
It is with this and similar instruments that the present invention enables the
number of currents to be reduced by half which would be required in telegraphing
according to any other method, as the discharge current generally following the
working current is completely done away with in telegraphing according to the
present invention, to which the working current itself is reversed each time and
nevertheless produces at the receiving station similar results.
It remains now to consider the practical application of the new method and to
examine the principal cases offered by the problem as a whole.
The invention will be better understood with reference to the accompanying
diagrammatic drawings, in which
Figure 1 shows the application of the new method to the transmission of signals
of unequal duration (such for instance as Morse signals).
Figures 2, 3 and 4 are modifications of the arrangement shown in Figure 1.
Figures 5 and 6 show the position of condensers on the battery in the case of
on lines with interposed condensers.
'
Figures 7 and 8 are modifications of the device shown in Figure 1.
Figure 9 shows the application of the invention to a double Baudot transmitting
apparatus with a 24 contact distributor.
Figure 10 shows the application of the invention to a Hughes instrument on
ordinary lines.
Figures 11 and 12 show the application of the invention to a Hughes apparatus
on lines with interposed condensers.
Figure 13 is the application of the invention for reception with the Hughes
apparatus.
Figures 14, 15 and 16 are modifications of the application shown in Figure 13.

page_text: Figure 17 shows the application of the invention to the transformation of line-
currents of unequal length into short equal local currents.
Figures 18 and 19 are modifications of the application shown in Figure 17.
Figure 20 is a constructive detail of the device shown in Figure 19.
Figures 21, 22 and 23 relate to the strengthening relay for the application of
the method to long-distance lines.
Figure 24 shows a simple arrangement of relays that can be used with the
system according to the present invention.
Figure 25 shows a double relay of the same kind.
Figures 26 and 27 show modifications.
Transmission by reversals of equal charges on cables provided at both ends
with condensers and by reversals with or without compensation at the receiving
station of continuous or limited currents of any duration on underground or
aerial lines.
For signals of unequal duration to be transmitted on cables with interposed
condensers the duration of the currents sent must be nevertheless equal and the
currents must alternate in order to make the transmitted charges_equal.
Figure 1 shows one of the numerous devices that can be used.
The currents sent by the transmitting apparatus with unequal signals-Morse,
Baudot, etc., (Figure 1) are received at the transmitting station by two polarised
relays A and B regulated so that one works only when a current of a certain sign
passes, and the other only with a current of an opposite sign.
By means of a condenser C placed in the circuit of these relays these latter
transform currents of unequal duration which they receive, into currents of equal
duration which will be transmitted through the line.
By lowering the Morse signalling or operating key D a charging current
actuates say the relay A whereupon an instantaneous positive current from the
battery A¹ is sent through the line. By raising the key which by means of the
contact at the other end is connected to earth, the discharge of the condenser
takes lace and actuates the second relay B whereupon an instantaneous negative
current is sent into the line by the battery B¹. The earth with which the key is
connected when in position of rest, can be replaced by a battery with an opposite
pole.
Figure 2 shows another arrangement.
An operating or signalling key D (Morse or other) sends-according as it is in
working position or in the position of rest-a positive or negative current into the
primary circuit of an induction coil E. In the secondary circuit are placed two
relays A and B operated as before by different currents. To each lowering of
the key will therefore correspond a short positive current in the line whatever be
the duration of the signal, and to each raising of the key will correspond an
equally short negative current on the line whatever be the duration of rest.
The relays are arranged so as to return automatically to the position for rest and
work alternately under the instantaneous action of the induction currents of
different signs.
Figure 2 shows an induction coil with two circuits and two batteries for the
key D. In Figure 3 the key has only one battery but the induction coil is pro-
vided with three circuits.
In the preceding cases the two combined relays in the position of rest can be
replaced by a single relay a in the intermediate position as shown in Figure 4.
A condenser say charged or discharged according to the position actuated by
the key and the relay in the intermediate position actuated by these charging or
discharging currents sends into the line a positive or negative current of short
duration, from the batteries A¹ or B¹.
It will also be seen in Figures 1, 2 and 3 that the line 1, 2, 3, 4 even in the
apparatus with two currents, is set for receiving after each transmission and the
message is recorded at the transmitting station-if the apparatus be of such con-

page_text: struction as to allow it-by means of a shunt resistance F with or without self-
induction. This detail is shown in Figure 1.
If transmission takes place on a cable with interposed condensers, the con-
denser may be attached to the line in the ordinary manner or to the battery_in
accordance with the two arrangements shown in Figures and 6 with ona relay
or two combined relays, the condensers in Figure 5 being indicated by letters H
and H and in Figure 6 by the letter H.
In Figure 5 the earthing at the point G is optional, according to the effect to
be obtained, but in all cases the two batteries A and B¹ remain connected with
each other either through the earth or by means of an insulated wire.
Figure 7 is also a device to be used for irregular signals with short and equal
currents. The combinations indicated above are applicable in this case in which
it will be seen that the currents sent are regularly interrupted by means of a
shunt passing through two successive relays A and B, with or without a resis-
tance c and with or without condenser C in the shunt.
The two contact pieces dd¹ of the signalling key D are respectively in relation
with the two bodies of the relays (d with A, d' with B). When the key is lowered,
a positive current from the battery A' is sent into the line 1 and, as shunt, into
the two relays A and B, which become operative. At this moment the positive
battery A is cut out, and the negative battery B' again connected to the contact
piece. As soon as the key touches said contact piece a negative current is
sent through the line 1 and a shunt into the relays A and B, which operate in
the inverse way. At this moment the negative battery B¹ is cut out in its turn,
and the positive battery A¹ again connected to the contact-piece d, and so on.
The relays A and B are set so that their armatures remain when attracted in
either end position.
It is obvious that these relays may have small resistance and be arranged on
the line either in parallel or in series. Figure 8 shows clearly how with say the
duplex system (other means will be described for Baudot) the line can be insu-
lated each time after sending a current according to the present invention the
receiver I remaining nevertheless in the circuit.
It is obvious that the Morse signalling key shown here for the sake of sim-
plicity can be just as well replaced by a Wheatstone signalling key. In the
latter case the transmission of unequal signals with equal currents becomes even
more simple.
It is sufficient to keep the terminals of the compensating resistance isolated.
To finish with examples of instruments with irregular signals which could be
continued indefinitely the Baudot apparatus will now be considered.
It must be first pointed out that in all the applications of the system according
to the present invention, no mechanical modification of the apparatus in use is
required. In this way, in case of accident, any spare apparatus may be used.
This is a feature of the greatest importance.
The transmission of Baudot signals could be effected with the means herein-
before described. The irregular currents would then as before, be converted into
equal currents. But the distributor offers too many advantages from the point
of view of the regularity of the currents to be neglected.
To make the explanation clearer a double Baudot instrument on a cable of a
determined length will be described by way of example.
We will take an existing construction of distributor, one with 24 contacts (the
quadruple pattern) as the number 24 being divisible by 2-3-4-6-8 and 12
fortunately lends itself to all possible combinations.
On a cable of a certain length as simplex transmission at the same time in both
directions cannot be effected there is no necessity to provide separations between
the sectors. Only two contacts will therefore be required for the correction and
two series of 5 contacts for the two key boards or 12 contacts in all.
Two means present themselves for utilising the 24 contact distributor.

page_text: The first consists in connecting the contacts two and two in order to obtain
12 insulated contacts required for the double transmission.
These 24 contacts could also be connected 3 and 3 in order to constitute the
8 insulated contacts of a key board installation.
The second means of utilising a 24 contact distributor for the purposes of
double transmission, consists in causing 12 working contacts to alternate with
12 insulated contacts, for the double purpose of shortening the periods of sending
and avoiding short-circuiting at the moment of the brushes touching simul
taneously two adjoining contacts. This latter arrangement is illustrated in
Figure 9.
Each key J, J, J³, etc., of the key-board instead of being directly connected
to the corresponding division of the distributor actuates three local simple
relays ¹, or one relay with triple armature, and the combined armatures
of these relays are connected to the odd divisions K¹ K³ K³ etc., of the distributor,
the even divisions K K K remaining insulated.
The object of these combinations is to obtain the practical application of the
system according to the present invention of transmitting equal and alternating
charges
A reference to Figure 9 shows that any of the keys J J J5 can send the
current only of a sign opposite to that of the one sent by the preceding key.
As an example: the key J3 when depressed actuates its three local
relays. The armature of the relay is directly connected to the cor-
responding division K5 of the distributor. The contact piece which it touches
when at rest, is connected to the armature of the relay of the preceding key Ja.
The piece with which this relay is in contact when working, is connected to
the amature at the relay kot the preceding key J. The key Ja being lowered,
if the preceding key is in the position of rest, a positive current will be sent into
the division K of the distributor; if the preceding key was not at rest and const-
quently lowered the armature of the relay corresponding to the key J would
find its "working" contact insulated and consequently the division K5 of the
distributor would remain insulated. In fine any key raised will not send into
the corresponding division of the distributor a negative current unless the pre-
ceding key is lowered.
If it is desired to telegraph say the letter T the first key will send a positive
current, the second a negative the third a positive, the fourth a negative and
the fifth a positive.
In this case 5 alternate currents will be sent, separated from one another by the
isolation of the line.
To telegraph the letter O which is usually done with three positive and two
negative currents the first key will send a positive current, the 2nd and 3rd will
isolate the line. The fourth will send a negative current and the 5th will isolate
the line at the departure.
Thus the new method can be applied to the Baudot instrument and renders
its employment possible on submarine cables.
The insulated divisions of the distributor need not necessarily be equal to the
working divisions. It may be even found advantageous to make them unequal.
It is simply proposed to use one of the existing patterns.
The same applies to the operating key-board with relays. It may have as was
already originally done by Baudot for long aerial lines, keys with multiple con-
tacts. But as the pattern at present in use has simple contacts, a system of con-
tacts has been arranged outside the key-board so as to enable any apparatus to
be used for a cable, as in case of Hughes' apparatus.
Finally if desired it is possible by the same method, to obtain currents with
different electro-motive forces according to the time intervals between the signals.
As regards the recording of the message at the transmitting station for the
purposes of checking, it can be done not only by the well-known means, but also
by utilising local currents produced by each key to actuate the triple relays

page_text: corresponding to each of these keys. A portion of this current shunted would
actuate at the same time the recording instrument of the transmitting post
through the intermediary of the receiving distributor.
It is unnecessary to remark that the kevs J, J, J J J³ of the key-boards
being connected (relays being interposed) with the odd divisions of the distributor
for transmission, the relays for the recording instrument will be connected at
the arrival station to the corresponding divisions of the receiving distributor.
It is necessary, in short, that everything should agree both at the sending and
receiving station, with the electric modification at the transmission.
I have now come to the apparatus with regular signals with unequal intervals,
of which Hughes is the type most used.
The application of the present system of transmission by means of reversals
of equal charges is very easy and very advantageous.
The method of reversing may be mechanical or electrical, the latter however
is preferred, in order not to have to make any changes in the construction of
the apparatus.
The operation is extremely simple. Fig. 10 shows a transmitting lever L of
a Hughes apparatus, a reversing relay M, an induction coil M¹ and two batteries.
The relay set so that its armature remains when attracted in either end position
always has its armature connected to one or other of the batteries. This arma-
ture connects the battery to the working contact of the Hughes apparatus through
the intermediary of the primary circuit of small resistance of the induction
coil M¹.
In the secondary circuit are placed one or several coils of the reversing relay.
The working is very simple.
The transmitting lever being raised, a positive current, say, is sent through
the line, and a local induction current circulates in the relay in such direction
that it assists the armature to remain on its contact.
When the current ceases, a reverse induction current actuates the reversing
relay, and its armature comes in contact with the negative pole of the second
battery.
When therefore a second current is sent into the line it will be a negative
current, and a local current is again induced in the circuit of the relay in such
direction that the armature is held in contact still more securely.
When the primary current is interrupted, an induction current will again
actuate the reversing relay, and its armature will come in contact with the
positive pole of the first battery, and so on.
In short, the fact of a current being sent does not produce any changes while,
when said current is interrupted, the reversing relay is actuated. Therein lies
the gist of the whole method.
On underground and aerial lines the device can be used as illustrated in
the drawing. For submarine cables with condensers, an intermediate relay must
be interposed sending currents direct into the cable without passing through the
induction coil in which besides, these currents would have been too weak to act
in an effective way.
Fig. 11 shows an arrangement that could be used for cables. This arrange-
ment may be combined with a shunt with a resistance with or without self-
induction for recording the message at the transmitting station as already shown
with regard to Fig. 1.
The reversing relay can be also actuated by the discharge-current of a con-
denser C (Fig. 12), the charging current securing the armature to its contact,
exactly in the same manner as with an induction coil.
The means may vary indefinitely but it is useless to repeat details, as the method
according to the present invention is now clearly explained.
The transmission by reversals of poles has the important advantage of rendering
the residual charge of the line absolutely without effect on the receiver. When
the current has once influenced the receiver, another reversal of poles is required

page_text: to produce the same effect as before, instantaneous or otherwise, according to the
kind of apparatus used. It is well known that hitherto the residual electro-
static charge of a long line was the chief obstacle to be overcome so as to dis-
charge the line both at the departure and the arrival.
Arrangement of receiving station for currents sent under the hereinbefore
described conditions.
All signals, without exception are transmitted by reversals of poles. A sensi-
tive relay will indicate each of these reversals by a momentary or permanent
displacement of its armature.
In the apparatus with signals of unequal duration such as Morse and Baudot,
the armature will always correspond to the position of work or rest, according
to the sign of the current received.
When, on the contrary, Hughes apparatus is used, the reversals of poles, what-
ever be the sign, always correspond to the same work to be done. The signal
received must therefore be transformed at the arrival station.
For this purpose the method indicated in the operations for transmission by
means of short currents, whatever be the duration of signals, Figures 1, 2, 3, 4 etc.
could be used but preferably the arrangement shown in Fig. 4 as it is simpler.
The positive and negative batteries connected to the two contact-pieces of the
relay must, for the Hughes apparatus, be replaced by the same positive battery.
This or these local relays are actuated by the line relay as indicated in Figure 13.
n is the reception-relay actuated by line-currents; by means of the movements
of its armature it actuates instantaneously a relay n in intermediate position, in
the current of which is placed a condenser N having the same function as the
condenser C of Figure 4. The bolts forming contact-pieces of the relay n, are
connected to the receiver and the armature of a local battery.
In some cases, the relay n in the intermediate position can be placed directly
on the line as a receiving relay. Then it would form the only interposed part
between the line and the Hughes apparatus.
Further, a series of constructions of relays operated by reversals and not
influenced by continuous currents, may be described, or a few of them may be
given as examples.
The idea underlying their construction is generally the instantaneous dif-
ferential action which can be obtained by a suitable combination of condensers
and of self-induction coils.
Figure 14 shows an arrangement that can be advantageously used on under-
ground or aerial lines without condensers, in order to operate by reversals of
poles.
Figure 15 is a differential compound arrangement. The windings are such that
the electro-magnetic action is nil under normal conditions. But in case of
reversals of poles, the working takes place by the unsymmetrical action of the
condenser O in combination with the self-induction coil O'.
Figure 16 is a double compound relay giving the same result. It consists of
two simple relays connected to each other somewhat in the manner of an opera-
glass, the armatures being secured together, and the contact-rod placed in the
centre on the common spindle of the two armatures.
All these devices are uninfluenced by earth currents and consequently need no
regulating, if the currents are sent alternately.
It does not even matter whether the receivers arranged in this manner be
actuated by continuous or limited currents. They are therefore very suitable
for being used on great over land lines.
There is also another series of devices that can be used on a line, but more
particularly in a local circuit; these are the combined relays.
Figure 17 shows a line-relay with alternative position according to the last
current received, actuating in its turn two relays combined so as to work suc-
cessively.
1
There are many means by which this may be effected. The following is a

page_text: typical instance. Between the two relays may be interposed a condenser O
which assists the first to the detriment of the second, then any coil O¹, with or
without self-induction retarding still more the working of the second relay.
When in the position of rest, the armatures, one of which is connected to a local
battery and the other to the receiving apparatus, are insulated from each other.
But if the first relay becomes operative before the second, the two armatures are
connected for an instant by means of the two inner set-screws, and an instan-
taneous current is sent into the receiver. For the return, that is to say, at the
second reversal of the poles, the first relay again becomes operative before the
second, but this time the instantaneous short current is produced by the outer
set-screws, and so on.
If it were desired to retransmit to the receiver the reversed instantaneous
currents, it would be sufficient to make the slight modification indicated in
Figure 18. This method may be varied and applied in different ways, for
instance for the discharge of lines both at the departure and at the arrival in all
ordinary installations at present in use.
Finally there is a very advantageous combination which may be called an
electro-diamagnetic bridge."
This is a bridge in which the current passes through the diagonal only during
a variable period, that is to say at the reversals of the sign of the current, which
is the fundamental idea of our system of transmission. It remains therefore un-
influenced by earth-currents.
The electro-diamagnetic bridge enables any apparatus to be used in the various
herein before described receiving arrangements.
In Figure 19 the resistance of the normally equal branches could be unequal.
PP are neutral resistances. Q and Q¹ resistances with self-induction. Two
condensers RR¹ of any construction decrease still greater the effect of the resis-
tances PP at the moment of reversal of the currents. At first the current
stopped by the self-induction of the branches Q and Q¹ follows the path indicated
by the arrows.
Under normal conditions, the currents, also divided, do not pass through the
receiver. The limited or continuous currents are therefore transformed into
instantaneous currents at each reversal of the poles.
other
To further supplement the action of the mutual induction to that of the self-
induction of the coils Q and Q', they could be wound on the same frame, and
finally in order to have only one kind of coils (neutral or with self-induction),
they can be similar, the circuits being coupled in a different way in the first case,
to avoid self-induction, in the second to make the self-induction as strong as
possible (Fig. 20).' The electro-diamagnetic bridge also possesses
qualities. In a general way, any device constituting an electro-diamagnetic
receiver possesses the property of doing at the interval end what is usually done
at the transmission end in certain apparatus such, for instance, as Wheatstone,
which sends compensated currents when the signal is long in order to avoid sur-
charging the line or over magnetising the receiver.
With an electro-diamagnetic arrangement of the receiver, the action of the
current at the receiving end can be graduated according to its duration, by giving
to the neutral branches a smaller resistance than that of the branches with self-
induction. Then, after a maximum action, a weak current of the same sign is
obtained in the receiver.
This method of effecting the compensation of the currents--not at the starting
end, as has been done hitherto, but at the receiving end-admits of a better
more precise regulation, as the reception is there to indicate to the operator the
direction in which the action ought to take place.
The contrary could be also done and the armature withdrawn without the

page_text: During the
current being reversed. It is sufficient for this purpose to make the neutral
branches of greater resistance than those with self-induction.
variable period, the current is stronger in the neutral branches owing to the self-
induction of the other branches, but under normal circumstances the reverse is
the case.
The result is the reversal of the sign of the current in the receiver without the
reversal of the current received from the line.
The different combinations hereinbefore described have the double advantage
over all hitherto known systems, of being uninfluenced by earth-currents and not
requiring regulating. These are extremely valuable properties not only for
receivers arranged at the end of a line, but also and more particularly for inter-
mediate transmission by relays.
System of Transmission by Relays. For a long distance line the transmission
system according to the present invention may be used with the relays of the con-
struction used at present, but it is rendered still more convenient according to
the following arrangement:-
The system, unlike all others, avoids the necessity of cutting the line. The
relays are simply arranged in shunt at the desired intermediata points, and
constitute so many shunts favourably influencing the discharge of the line, while
substituting for the current received, a new current which retransmits the signal
to the following relay. These relays can also be successively arranged on the
line, but this arrangement is not so good.
These relays may be employed in many different ways. They may be utilised,
with modifications of secondary importance, either with limited currents or with
continuous currents, for the transmission of signals, according to this invention,
by reversals of poles.
In order not to describe too many examples, only the method with continuous
currents will be indicated.
Fig. 21 shows a line y with a strengthening relay shunted at S.
The relay has differential winding, but the shunt-current passes both the cir-
cuits in the same direction and the effects are added. The armature communi-
cates with the head of the differential system as well as a condensers, of any
suitable construction, increasing the action of the line currents. The contact-
screws communicate, one with a positive battery, and the other with a negative
battery. At S¹ there is suitable resistance which, however, is optional in certain
cases. The position of the batteries of the relay is such that a positive line-
current places the armature on the contact of the battery of the same sign, a
negative line-current places the armature on the contact connected to the
negative battery.
It will be seen that in these conditions the current of the relay, of the same
sign as that in the line, stops the latter so to say in order to take its place on the
side nearer the receiving post.
If the line current goes, say, from z towards y, the current from the relay,
under normal circumstances is blocked on the side of and goes to y..
Any current coming from the line passes through the two windings of the
relay in the direction indicated by the arrow, it is therefore necessary that the
local current of the strengthening relay should pass through the two circuits of
the latter without disturbing its working, but on the contrary, helping it when
required. This is attained by causing the current from the battery to divide
into two branches suitably determined by means of the resistance S¹, or the pro-
portion between the two windings.
The following is one of the most remarkable points about this relay. When the
transmitting post reverses its poles, the battery of the relay adds its action to that
of the transmission post, and under this double impulse, the relay works well
and without hesitation.
The armature becoming connected with the battery of the same pole as that
of the corresponding one the battery of the relay becomes substituted for that of

page_text: the line in order to continue sending a current in the same direction as before.
The local current passing through the coil on the side opposite to the line, main-
tains the armature in its new position and so on.
This strengthening relay may have different forms it may be even used, in
certain cases, at the heads of a line, in combining (in series or shunts) with one
of the methods of reception herein before described, according to the requirements
of the apparatus used.
This apparatus could be used even on cables with condensers where it would
considerably increase the favourable action of the latter.
When regulated so that its armature will remain, when attracted, in either end
position and arranged according to the electro-diamagnetic system, as shown in
Fig. 22 or arranged on the diagonal of an electro-magnetic bridge (Fig. 23), the
strengthening relay has no regulating device and is not influenced by earth
currents. It could therefore be used with advantage on long underground
lines, the numerous shunts which the method comprises, reducing the incon-
veniences of the great capacity of the cables without dividing the line into sec-
tions, as is done by the ordinary relays. It is useless to enumerate all the advan-
tages and different applications of apparatus possessing such properties.
Fig. 22 shows a relay arranged according to the electro-diamagnetic system.
The chief difference between this and Fig. 21 lies in the different methods of
coupling the circuits. The line currents pass through the two circuits in opposite
directions so that they have normally no influence. At the moment of the
reversal of the poles, the apparatus becomes operative owing to the unsymmetrical
action of the condenser s combined with one or more coils with or without self-
induction. The double relay herein before described may also be used, in this way
the inducing action of one circuit on the other is avoided, and the self-induction
of the second circuit better utilised.
Finally, it will be seen (Figs. 22 and 26) that it is always possible to arrange a
controlling receiver S¹ (at the transmitting station) operated directly by the
reversal of the poles or through the intermediary of a local relay.
Duplex Telegraphing.-Duplex telegraphing according to the present inven-
tion, is effected simply according to any of the methods at present in use, adapted
to suit the new system.
Different Applications.-Owing to certain important properties of the system
according to the present invention the chief of which is that it does not require
a regulating device and is not influenced by earth currents, its applications are
very numerous.
It is therefore unnecessary to enumerate them in detail except one which
appears to be worthy of special notice. That is, the possibility of constituting
similarly to electric net for lighting, general telegraphic nets which could be
aerial, but which might be preferably, underground, in order to be protected
against storms etc.
These nets would be probably placed in the hands of the State for transmitting
official messages simultaneously to a number of stations. But as a source of
revenue they could be leased to or used by news' agencies etc. for transmitting
press-news to a large number of newspapers at once.
These messages would then be transmitted directly from the central office of
the agency to different provincial branch offices.
The control of the State could be always ensured by means of a receiver
branched on the line and placed in one of the Government offices. This control
would have for its principal purpose to render impossible transmission of secret
messages.
At the present time, with the progress accomplished in the manufacture of
underground cables and the always increasing desire for rapid information this
creation of press-nets would appear to be opportune and valuable.
Apparatus. As is apparent from the preceding description, the present inven-
ion relates more to an improved method of telegraphing wherein existing

page_text: apparatus, so that, if necessary, the apparatus actually in use may be employed
for telegraphing according to the new system.
As, however, for the sake of simplicity and sometimes as improvements,
several modifications have been made in the ordinary apparatus, they may be
referred to as follows:-
On submarine cables receiving instruments of Lord Kelvin, Lauritzen, and
other similar instruments may be used, without any other modification except
the necessary addition in order to employ them as relays. This needs no further
explanation.
The unifilar or bifilar suspension may also, sometimes, be done away with and
the movable part be placed between fixed points or on very delicate knife edges
when passing from the vertical into the horizontal position.
In order to impart to these receivers certain properties which will sometimes
be necessary, they are modified to an extent so as to practically make of them
new apparatus.
1. In order to obtain a sensitive relay with the position of the armature in-
differently on one or the other contact piece, a movable galvano-metric frame
with a light needle of soft iron is placed in the field of a powerful magnet or
electro-magnet of any shape and size, so that the needle should be normal to
the plane of the windings.
The zero-position is adjusted by means of a light contact-lever oscillating
between two contact-screws.
This relay with the needle normal to the line of its poles is just the reverse of
the Marcel Deprez galvanometer.
In the present apparatus the needle or movable part is magnetised by the
current and deflected by the magnet. In the Marcel Deprez galvanometer the
needle or movable part is magnetized by the magnet and deflected by the current.
The present apparatus may be adjusted so as to remain on the contact to which
it is attracted, for the purpose in view. In the Marcel Deprez apparatus the
movable part or needle is, on the contrary, strongly directed.
Finally, in the system according to the present invention the frame may be
fixed and independent of the needle or movable part, or secured to it, and
participating in its motion. In this case the electro-magnetic and the electro-
dynamic actions support each other.
In order to convert this apparatus into a relay with intermediate position, it
is sufficient to arrange one or several needles of the movable part normally to the
others, that is to say in the direction of the magnetic poles, and the movable part
always returns into a fixed position after having been deflected.
It will be seen besides that this system of directing or controlling is applicable
even in case when the motive movable part is done away with. The movable
part, of course will be supported between points or on knife-edges. It is useless
to describe these details which are well known to all electricians.
For underground or aerial lines and different local combinations herein before
described, a pattern has been designed which combines great simplicity of con-
struction, great sensitiveness and rapidity with a minimum of self-induction. Its
essential parts will be now fully described, the minor constructional details being
the same in all the relays.
Referring to Fig. 24; it comprises (1) A magnet T, preferably of circular
shape or it may be of any other shape, with or without set-screws for varying
the space between the poles.
(2) A coil T¹ placed in the centre of the magnet and having in its centre the
armature T movable between points or on knife-edges above the neutral line of
the magnet.
This armature oscillates between two insulated contact screws mounted on the
poles of the magnet or in any other way.
This relay, the dimensions of which may be any desired, will comprise_two
chief kinds the simple and the double forms. The simple form has just been

page_text: described, the double form (Fig. 25) consists of two similar apparatus mounted
For this
on the same foundation but having one contact-rod t in common.
purpose a rigid spindle carrying the two armatures and the contact-rod in the
centre pivots between points as shown in Figure 25.
These two constructions of relays are both such that the armatures can remain
in any position. In order to convert them into relays with an armature always
returning into the central position, it is sufficient to place the movable part
under the influence of a suitable spring or some magnetic device.
Finally, a relay, of a different pattern from the preceding one will be described,
the difference being that the core armature instead of oscillating in the coil pivots
about its axis and carries either at one or at both ends, polar appendices the ends
of which move between the poles of 12 or 4 magnets arranged for this purpose.
The passage of the current through the coil polarises the core and its polar
appendices. The sign of this magnetisation determines the direction of move-
ment.
This kind of relay can be arranged in various forms, but Figures 26 and 27
give a sufficiently clear idea of the construction.
It will be seen that the core w is in the centre of the coil W and is movable
between points and is provided with polar appendices w¹ each oscillating between
the two poles of a magnet W¹.
For a relay with one magnet, the core is provided only with one polar appendix,
for a relay with two magnets it has two appendices and so on.
T
1
0041
low of Tonuary 1898
BOULT & WADE,
Agents for the Applicant.
Improvements in or relating to Electric Telegrapny.
I, PIERRE PICARD, of 95, Boulevard Beaumarchais, Paris, in the Republic of
France, 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:-
Experts know how many difficulties are met when it is proposed either to
increase the efficiency of submarine cables or to use for them a synchronous
apparatus. such, for instance, as Hughes', whilst as regards Baudot's apparatus,
nobody would think of using it for cables of a considerable length. even inferior
to that of the Franco-Algerian cables.
The failures in this respect depend on the incompatibility of the laws of electric
propagation in cables of great electro-static capacity with the necessary irregu-
larity of signals to be transmitted.
"
In order that & current sent from a station may produce its effect at the distant
end of a cable in a neutral state, a certain perfectly definite time is required, and
the successivo signals would be transmitted quite correctly, if the cable were
always brought back into its original condition. This result is approached if
each current sent say a positive is immediately followed by a neutralising say a
negative current.
But the last residual negative charge is not always constant and depends on
the time which elapses before the next positive current is sent. But these time-
intervals being extremely variable in the Hughes apparatus the successive cur-
rents sent have their nature altered and at their arrival at the other end, their

page_text: effects do not take place at sufficiently precise periods. If, however, the variations
remain within the limits of error of the instrument, the transmission is, of course,
still possible, but requires considerable correction.
The feature which more particularly distinguishes the system according to the
present invention from all others hitherto used or tried, especially as regards the
synchronous apparatus, is the absolute abandonment of the idea or practice of
bringing the cable back into a neutral condition each time after sending a working
current. In this new system the charge of the cable does not vary between two
successive sendings of the current, and as the working currents in this method
are always sent alternately they always find the cable in a symmetrically similar
state. In other words, a positive current finds the cable with a determined nega-
tive charge, a negative current finds it with a positive charge equal to the previous
negative one and so on.
Attempts have also been made to devise a system of signals enabling the
greatest possible speed to be attained. The utmost limit reached was the trans-
mission of signals of equal duration and combined as to signs without regard to
the alternation. These are the signals of the syphon recorder.
The method according to the present invention is based on the absolute alterna-
tion of signs combined with the equality of charges, the intervals between them
not being taken into consideration.
This method is applicable to all kinds of apparatus.
The Wheatstone apparatus could therefore be used on transatlantic cables.
Even the Baudot instrument. at a reduced speed compatible with the length of
the cable, could be used. between say. Paris and New York, with relays at the
land ends, the use of relays with a variable zero being useless in the method
according to the present invention. In these conditions, the efficiency of the
Baudot apparatus will certainly not be less than that of the syphon recorder; the
signals of which, being defective owing to the irregular succession of currents of
the same sign, necessitate frequent corrections.
The advantages of the alternation of the currents are, besides, plainly shown
by the strips of the recorder. on which every reversal of the polarity produces a
much sharper curve. It results therefrom that equal alternate charges can follow
each other quicker.
It must be kept in mind that on the sharpness of the curve received depends
the clearness of the signals.
In other words it can be said that absolute alternation is equivalent in practice
to currents of opposite signs being sent nearly simultaneously at both ends of a
cable with interposed condensers. The result of this is a sharpness of the curve
and the possibility of increasing the speed of transmission.
The working of great telegraphic lines has raised three main questions which
come more and more to the front owing to the growing exigencies of communica-
tion. They are
(1) That of submarine lines.
(2) That of underground lines.
(3) That of long aerial lines.
In all the three cases the real serious difficulty resides in the great electro-static
capacity of the lines.
It is natural to begin with submarine lines which, as soon as they attain a
certain length, require all the possible perfection required for other lines in order
to give a suitable efficiency.
The method of transmission according to the present invention by reversals of
equal electro-static charges, whatever be the nature and duration of the signals to
be transmitted, will be described first in the application to submarine cables.
As regards underground and especially aerial lines, it will be seen that by
applying the method of alternation large reductions of the duration of contact 5
will become possible.
Speaking in a more general way, the method according to the present invention

page_text: PP
is as follows;
США онощение инистутовна от
-
AKU
(1) Transmission by reversals of equal charges on cables with condensers inter-
posed at both ends (which is the case in submarine cables).
(2) Transmission by reversing poles with or without compensation at the receiving
station, of continuous or limited currents of any duration on underground or
aerial lines, earthed at both ends.
The problem as a whole comprises:
(1) Transmission by reversing poles, whatever be the nature and duration of
signals.
(2) Means of reception capable of utilising the currents sent under the above con-
ditions.
etc.
(3) Applications to different instruments, Morse, Wheatstone, Hughes, Baudot,
(4) Translation.
(5) Arrangement in duplex.
In order to communicate equal alternate charges to a condenser, it must be
connected during equal intervals with sources alternately positive and negative
and of equal electro-motive forces.
From this well-known principle necessarily it follows that the condenser (repre-
sented by the cable and condensers which terminate it) must be removed from any
influence which could modify its electric state in any manner whatever, between
the alternating charges which succeed one another at unequal intervals. It is
therefore necessary to avoid earthing it during the variable periods. But the
cable may be isolated, say, between each time that a current is sent so that in this
way anything that could irregularly alter the state of the line at the sending
station will be avoided as far as possible.
The transmission of equal charges is effected either by direct currents from a
battery or by discharges of the condensers of the transmitting station or by the
combination of the two for equal periods in each case.
On sufficiently short lines or cables the transmission could sometimes be effected
by means of induction currents. But, in this case, the currents succeeding one
another at unequal intervals, find the line in different states, and the nature of the
signals is altered if the line is too long, owing to the conductor not being isolated
between each sending of the current.
Although in theory the line is isolated after each sending of a current (the
alternation being absolute and the contacts of equal duration), it is obvious, that
according to the nature of the cables, this isolation can be replaced by a connection
to earth for a determined period succeeded by an isolation, or even, by connecting
it with one or several condensers charged to a determined potential. The right
is therefore reserved of using all possible combinations of batteries, earth and con-
densers with or without isolation at the transmitting station, according to cir-
cumstances.
Finally the currents can be also sent by placing the source in shunt on any
point of the line teminated at both ends by receivers and provided with condensers.
In this case the transmitting and the receiving are the same.
The contacts producing the current being of equal duration, the charges pro-
duced will be equal. With apparatus in which the currents have to produce at
the receivers signals of unequal duration, such for instance, as Morse, Wheatstone,
Baudot, etc.. it is preferable to make the position of the armature of the receiving
relay agree with the sign of the currents sent.
Hughes apparatus is altogether different and is always worked by currents of
equal duration but divided by unequal intervals.
It is with this and similar instruments that the present invention enables the
number of currents to be reduced by half which would be required in telegraphing
according to any other method, as the discharge current generally following the
working current is completely done away with in telegraphing according to the

page_text: present invention, in which the working current itself is reversed each time and
nevertheless produces at the receiving station similar results.
It remains now to consider the practical application of the new method and to
examine the principal cases offered by the problem as a whole.
The invention will be better understood with reference to the diagrammatic
drawings accompanying the Provisional Specification, in which
Figure 1 shows the application of the new method to the transmission of signals
of unequal duration (such for instance as Morse signals).
Figures 2, 3 and 4 are modifications of the arrangement shown in Figure 1.
Figures 5 and 6 show the position of condensers on the battery in the case of
a cable with interposed condensers.
Figures 7 and 8 are (modifications of the device shown in Figure 1.
Figure 9 shows the application of the invention to a double Baudot transmitting
apparatus with a 24 contact distributor.
Figure 10 shows the application of the invention to a Hughes' instrument on
ordinary lines.
Figures 11 and 12 show the application of the invention to a Hughes' apparatus
on lines with interposed condensers.
Figure 13 is the application of the invention for reception with the Hughes
apparatus.
Figures 14, 15 and 16 are modifications of the application shown in Figure 13.
Figure 17 shows the application of the invention to the transformation of line-
currents of unequal length into short equal local currents.
Figures 18 and 19 are modifications of the application shown in Figure 17.
Figure 20 is a constructive detail of the device shown in Figure 19.
Figures 21, 22 and 23 relate to the strengthening relay for the application of
the method to long-distance lines.
'
Figure 24 shows a simple arrangement of relays that can be used with tho
system according to the present invention.
Figure 25 shows a double relay of the same kind.
Figures 26 and 27 show modifications.
Transmission by reversals of equal charges on cables provided at both ends
with condensers, and by reversals with or without compensation at the receiving
station of continuous or limited currents of any duration on underground or
aerial lines.
For signals of unequal duration to be transmitted on cables with interposed
condensers the duration of the currents sent must be, nevertheless, equal and the
currents must alternate in order to make the transmitted charges equal.
Figure 1 shows one of the numerous devices that can be used.
The currents sent by the transmitting apparatus with unequal signals-Morse,
Baudot, etc. (Fig. 1) are received at the transmitting station by two polarised
relays A and B regulated so that one works only when a current of a certain sign
passes, and the other only with a current of an opposite sign.
By means of a condenser C placed in the circuit of these relays these latter
transform currents of unequal duration which they receive, into currents, of equal
duration which will be transmitted through the line.
By lowering the Morse signalling or operating key D a charging current
actuates say the relay A, whereupon an instantaneous positive current from the
battery A¹ is sent through the line. By raising the key which by means of the
contact at the other end is connected to earth, the discharge of the condenser
takes place and actuates the second relay B whereupon an instantaneous negative
current is sent into the line by the battery B¹. The earth with which the key is
connected when in position of rest, can be replaced by a battery with an opposite
pole.
Figure 2 shows another arrangement.
An operating or signalling key D (Morse or other) sends according as it is in
working position or in the nosition of mot

page_text: primary circuit of an induction coil E. In the secondary circuit are placed two
relays A and B operated as before by different currents. To each lowering of
the key will therefore correspond a short positive current in the line, whatever be
the duration of the signal, and to each raising of the key will correspond an
equally short negative current in the line whatever be the duration of rest.
The relays are arranged so as to return automatically to the position of rest and
work alternately under the instantaneous action of the induction currents of
different signs.
Figure 2 shows an induction coil with two circuits and two batteries for the
key D. In Figure 3 the key has only one battery, but the induction coil is pro-
vided with three circuits.
'
In the preceding cases the two combined relays in the position of rest can be
replaced by a single relay a in the intermediate position as shown in Figure 4.
A condenser, say, is charged or discharged according to the position occupied by
the key and the relay in the intermediate position actuated by these charging or
discharging currents, sends into the line a positive or negative current of short
duration, from the batteries A¹ or B¹.
It will also be seen in Figures 1, 2 and 3 that the line 1, 2, 3, 4 even in the
apparatus with two currents, is set for receiving after each transmission and the
message is recorded at the transmitting station if the apparatus be of such con-
struction as to allow it-by means of a shunt resistance F with or without self-
induction. This detail is shown in Figure 1.
If transmission takes place on a cable with interposed condensers, the con-
denser may be attached to the line in the ordinary manner or to the battery in
accordance with the two arrangements shown in Figures 5 and 6 with one relay
or two combined relays, the condensers in Figure 5 being indicated by letters H
and Hand in Figure 6 by the letters H.
In Figure 5 the earthing at the point G is optional, according to the effect to
be attained, but in all cases the two batteries A¹ and B¹ remain connected with
each other either through the earth or by means of an insulated wire.
Figure 7 is also a device to be used for irregular signals with short and equal
currents. The combinations indicated above are applicable in this case in which
it will be seen that the currents sent are regularly interrupted by means of a
shunt passing through two successive relays A and B with or without a resis-
tance and with or without condenser C in the shunt.
The two contact-pieces dd of the signalling key 1) are respectively in relation
with the two bodies of the relays (d with A, d' with B). When the key is lowered,
a positive current from the battery A¹ is sent into the line 1 and, as shunt, into
the two relays A and B, which become operative. At this moment the positive
battery A is cut out, and the negative battery B₁ is again connected to the contact-
piece d. As soon as the key touches said contact piece a negative current is
sent through the line 1 and a shunt into the relays A and B which operate in
the inverse way. At this moment the negative battery B' is cut out in its turn,
and the positive battery A¹ again connected to the contact-piece d, and so on.
The relays A and B are set so that their armatures remain when attracted in
either end position.
It is obvious that these relays may have small resistance and be arranged on
the line either in parallel or in series. Figure 8 shows clearly how with, say the
duplex system (other means will be described for Baudot), the line can be insu-
lated each time after sending a current, according to the present invention. The
receiver I remaining nevertheless in the circuit.
It is obvious that the Morse signalling key shown here for the sake of sim-
plicity can be just as well replaced by a Wheatstone signalling key. In this
latter case the transmission of unequal signals with equal currents becomes even
more simple.
It is sufficient to keep the terminals of the compensating resistance isolated.

page_text: To finish with examples of instruments with irregular signals which could be
continued indefinitely the Baudot apparatus will now be considered.
It must be first pointed out that in all the applications of the system according
to the present invention, no mechanical modification of the apparatus in use is
required. In this way, in case of accident any spare apparatus may be used.
This is a feature of the greatest importance.
The transmission of Baudot signals could be effected with the means herein-
before described. The irregular currents would then, as before, be converted into
equal currents. But the distributor offers too many advantages from the point
of view of the regularity of the currents to be neglected.
To make the explanation clearer, a double Baudot instrument on a cable of a
determined length will be described by way of example.
We will take an existing construction of distributor one with 24 contacts (the
quadruple pattern) as the number 24 being divisible 2-3-4-6-8 and 12 fortunately
lends itself to all possible combinations.
On a cable of a certain length, as simplex transmission at the same time in both
directions cannot be effected, there is no necessity to provide separations between
the sectors. Only two contacts will therefore be required for the correction and
two series of 5 contacts for the two key-boards or 12 contacts in all.
Two means present themselves for utilising the 24 contacts distributor.
The first consists in connecting the contacts two and two in order to obtain
12 insulated contacts required for the double transmission.
These 24 contacts could also be connected 3 and 3 in order to constitute the
8 insulated contacts of a key board installation.
The second means of utilising 24 contact distributor for the purposes of
double transmission, consists in causing 12 working contacts to alternate with
12 insulated contacts, for the double purpose of shortening the periods of sending
and avoiding short-circuiting at the moment of the brushes touching simul-
taneously two adjoining contacts. This latter arrangement is illustrated in
Figure 9.
Each key JJ Js etc. of the key hoard instead of being directly connected
to the corresponding division of the distributor, actuates three local simple
relavs or one relay with triple armature, and the combined armatures
of these relays are connected to the odd divisions K¹ K3 K5 etc. of the distributor,
the even divisions K K K remaining insulated.
The object of these combinations is to obtain the practical application of the
system according to the present invention of transmitting equal and alternating
charges.
A reference to Figure 9 shows that any of the keys J¹ Ja .. J5 can send the
current only of a sign opposite to that of the one sent by the preceding key.
As an example: the key J8 when depressed actuates it's three local
relays. The armature of the relay is directly connected to the cor-
responding division K of the distributor. The contact piece which is touches
when at rest, is connected to the armature of the relay of the preceding key J³.
The piece with which this relay is in contact when working is connected to
the armature of the relay of the preceding key J. The key Js being lowered,
if the preceding key is in the position of rest, a positive current will be sent into
the division K5 of the distributor; if the preceding key was not at rest and conse-
quently lowered, the armature of the relay corresponding to the key J³ would
find its "
working" contact insulated and consequently the division K5 of the
distributor would remain insulated. In fine any key raised will not send into
the corresponding division of the distributor a negative current unless the pre-
ceding key is lowered.
If it is desired to telegraph say the letter T the first key will send a positive
current, the second a negative, the third a positive the fourth a negative and
the fifth a positive.

page_text: In this case 5 alternate currents will be sent, separated from one another by the
isolation of the line.
To telegraph the letter O which is usually done with three positive and two
negative currents the 1st key will send a positive current the 2nd and 3rd will
isolate the line, the 4th will send a negative current and the 5th will isolate
the line at the departure.
Thus the new method can be applied to the Baudot instrument and renders
its employment possible on submarine cables.
The insulated divisions of the distributor need not necessarily be equal to the
working divisions. It may be even found advantageous to make them unequal.
It is simply proposed to use one of the existing patterns.
The same applies to the operating key board with relays. It may have as was
already originally done by Baudot for long aerial lines, keys with multiple con-
tacts. But as the pattern at present in use has simple contacts a system of con-
tacts has been arranged outside the key board so as to enable any apparatus to
be used for a cable, as in case of Hughes apparatus.
Finally if desired it is possible by the same method to obtain currents with
different electro-motive forces according to the time intervals between the signals.
As regards the recording of the message at the transmitting station for the
purposes of checking it can be done not only by the well known means, but also
by utilising local currents produced by each key to actuate the triple relays
corresponding to each of these keys. A portion of this current shunted would
actuate at the same time the recording instrument of the transmitting post
through the intermediary of the receiving distributor.
It is unnecessary to remark that the keys J₁ J, J, J J of the key-boards
being connected (relays being interposed) with the odd divisions of the distributor
for transmission, the relays for the recording instrument will be connected at
the arrival station to the corresponding divisions of the receiving distributor.
It is necessary in short, that everything should agree both at the sending and
receiving station, with the electric modification at the transmission.
We have now come to the apparatus with regular signals with unequal intervals,
of which Hughes is the type most used.
The application of the present system of transmission by means of reversals
of equal charges is very easy and very advantageous.
The method of reversing may be mechanical or electrical, the latter however
is preferred, in order not to have to make any changes in the construction of
the apparatus.
The operation is extremely simple. Figure 10 shows a transmitting lever L of
a Hughes apparatus, a reversing relay M, an induction coil M' and two batteries.
The relay set so that its armature remains when attracted in either end position
always has its armature connected to one or other of the batteries. This arma-
ture connects the battery to the working contact of the Hughes apparatus through
the intermediary of the primary circuit of small resistance of the induction
coil M¹.
In the secondary circuit are placed one or several coils of the reversing relay.
The working is very simple.
The transmitting lever being raised, a positive current, say, is sent through
the line, and a local induction current circulates in the relay in such direction
that it assists the armature to remain in its contact.
When the current ceases, a reverse induction current actuates the reversing
relay, and its armature comes in contact with the negative. pole of the second
battery.
When therefore a second current is sent into the line it will be a negative
current, and a local current is again induced in the circuit of the relay in such
direction that the armature is held in contact still more securely.
When the primary current is interrupted, an induction current will again

page_text: actuate the reversing relay and its armature will come in contact with the
positive pole of the first battery, and so on.
In short, the fact of a current being sent does not produce any changes while,
when said current is interrupted, the reversing relay is actuated. Therein lies
the gist of the whole method.
On underground and aerial lines the device can be used as illustrated in
the drawing. For submarine cables with condensers, an intermediate relay must
be interposed sending currents direct into the cable without passing through the
induction coil in which besides, these currents would have been too weak to act
in an effective way.
Figure 11 shows an arrangement that could be used for cables. This arrange-
ment may be combined with a shunt with a resistance with or without self-
induction for recording the message at the transmitting station as already shown
with regard to Figure 1.
The reversing relay can be also actuated by the discharge current of a con-
denser C (Figure 12) the charging current securing the armature to its contact
exactly in the same manner as with an induction coil.
The means may vary indefinitely but it is useless to repeat details as the method
according to the present invention is now clearly explained.
The transmission by reversals of poles has the important advantage of rendering
the residual charge of the line absolutely without effect on the receiver. When
the current has once influenced the receiver, another reversal of poles is required
to produce the same effect as before instantaneous or otherwise according to the
kind of apparatus used. It is well known that hitherto the residual electro-
static charge of a long line was the chief obstacle to be overcome so us to dis-
charge the line both at the departure and the arrival.
Arrangement of receiving stations for currents sent under the hereinbefore
described conditions.
All signals without exception are transmitted by reversals of poles. A sensi-
tive relay will indicate each of these reversals by an momentary or permanent
displacement of its armature.
In the apparatus with signals of unequal direction such as Morse and Baudot,
the armature will always correspond to the position of work or rest according
to the sign of the current received.
When on the contrary Hughes apparatus is used, the reversals of poles, what
ever be the sign, always correspond to the same work to be done. The signal
received must therefore be transformed at the arrival station.
For this purpose the methods indicated in the operations for transmission by
means of short currents, whatever be the duration of signals Figures 1, 2, 3, 4 etc.
could be used but preferably the arrangement shown in Figure 4 as it is simpler.
The positive and negative batteries connected to the two contact-pieces of the
relay must, for the Hughes apparatus, be replaced by the same positive battery.
This or these local relays are actuated by the line relay as indicated in Figure 13.
is the reception-relay actuated by line currents; by means of the movements
of its armature it actuates instantaneously a relay n in intermediate position, in
the circuit of which is placed a condenser N having the same function as the
condenser C of Figure 4. The bolts forming the contact-pieces of the relay are
connected to the receiver and the armature of a local battery.
In some cases, the relay n in the intermediate position can be placed directly
on the line as a receiving relay. Then it would form the only interposed part
between the line and the Hughes apparatus.
Further, a series of constructions of relays operated by reversals and not
influenced by continuous currents may be described, or a few of them may be
given as examples.
The idea of underlying their construction is generally the instantaneous dif-
ferential action which can be obtained by a suitable combination of condensers
and of self-induction coils.

page_text: "
Figure 14 shows an arrangement that can be advantageously used on under-
ground or aerial lines without condensers, in order to operate by reversals of
poles.
Figure 15 is a differential compound arrangement. The windings are such that
the electro-magnetic action is nil under normal conditions.. But in case of
reversals of poles, the working takes place by the unsymmetrical action of the
condenser 0 in combination with the self-induction coil O'.
Figure 16 is a double compound relay giving the same result. It consists of
two simple relays connected to each other somewhat in the manner of an opera
glass, the armatures being secured together, and the contact-rod placed in the
centre on the common spindle of the two armatures.
All these devices are uninfluenced by earth-currents and consequently need no
regulating, if the currents are sent alternately.
It does not even matter, whether the receivers arranged in this manner be
actuated by continuous or limited currents. They are therefore very suitable
for being used on great overland lines.
There is also another series of devices that can be used on a line, but more
particularly in a building: these are the combined relays.
Figure 17 shows a line-relay with alternative position according to the last
current received, actuating in its turn two relays combined so as to work suc-
cessively.
There are many means by which this may be effected. The following is a
typical instance. Between the two relays may be interposed a condenser 0
which assists the first to the detriment of the second, then any coil 01, with or
without self-induction retarding still more the working of the second relay.
When in the position of rest, the armatures, one of which is connected to a local
battery and the other to the receiving apparatus, are insulated from each other.
But if the first relay becomes operative before the second, the two armatures are
connected for an instant by means of the two inner set-screws, and an instan-
taneous current is sent into the receiver. For the return, that is to say at the
second reversal of the poles, the first relay again becomes operative before the
second, but this time the instantaneous short current is produced by the outer
set-screws and so on.
If it were desired to retransmit to the receiver the reversed instantaneous
currents, it would be sufficient to make the slight modification indicated in
Figure 18. This method may be varied and applied in different ways, for
instance for the discharge of lines both at the departure and at the arrival ends
in all ordinary installations at present in use.
Finally, there is a very advantageous combination which may be called an
lectro-diamagnetic bridge."
This is a bridge in which the current passes through the diagonal only during
a variable period, that is to say at the reversals of the sign of the current, which
is the fundamental idea of our system of transmission. It remains therefore un-
influenced by earth-currents.
The electro-diamagnetic bridge enables any apparatus to be used in the various
herein before described receiving arrangements.
In Fig. 19 the resistance of the normally equal branches could be unequal.
PP are neutral resistances. Q and Q' resistances with self-induction. Two
condensers R R¹ of any construction decrease still further the effect of the resis-
tances PP at the moment of reversal of the currents. At first the current
stopped by the self-induction of the branches Q and Q¹ follows the path indicated
by the arrows.

page_text: receiver. The limited or continuous currents are therefore transformed into
instantaneous currents at each reversal of the poles.
other
To further supplement the action of the mutual induction to that of the self-
induction of the coils Q and Q', they could be wound on the same frame, and
finally in order to have only one kind of coils (neutral or with self-induction)
they can be similar, the circuits being coupled in a different way in the first case,
to avoid self-induction, in the second to make the self-induction as strong as
possible (Fig. 20). The electro-diamagnetic bridge also possesses
qualities. In a general way, any device constituting an electro-diamagnetic
receiver possesses the property of doing at the arrival end what is usually done
at the transmission end in certain apparatus, such for instance, as Wheatstone,
which sends compensated currents when the signal is long in order to avoid sur-
charging the line or over magnetising the receiver.
With an electro-diamagnetic arrangement of the receiver, the action of the
current at the receiving end can be graduated according to its duration, by giving
to the neutral branches a smaller resistance than that of the branches with self-
induction. Then, after a maximum action, a weak current of the same sign is
obtained in the receiver.
This method of effecting the compensation of the currents-not at the transmission
end as has been done hitherto, but at the receiving end-admits of a better,
more precise regulation, as the reception is there to indicate to the operator the
direction in which the action ought to take place.
The contrary could be also done and the armature withdrawn without the
current being reversed. It is sufficient for this purpose to make the neutral
branches of greater resistance than those with self-induction. During the
variable period, the current is stronger in the neutral branches owing to the self-
induction of the other branches, but under normal circumstances the reverse is
the case.
The result is the reversal of the sign of the current in the receiver without the
reversal of the current received from the line.
The different combinations hereinbefore described have the double advantage
over all hitherto known systems, of being uninfluenced by earth currents and not
requiring regulating. These are extremely valuable properties not only for
receivers arranged at the end of a line, but also and more particularly for inter-
mediate transmission by relays.
System of Transmission by Relays. For a long distance line the transmission
system according to the present invention may be used with the relays of the con-
struction used at present, but it is rendered still more convenient according to
the following arrangement.
This system, unlike all others, avoids the necessity of cutting the line. The
relays are simply arranged in shunt at the desired intermediate points and
constitute so many shunts favourably influencing the discharge of the line, while
substituting for the current received, a new current which retransmits the signal
to the following relay. These relays can also be successively arranged on the
line, but this arrangement is not so good.
These relays may be employed in many different ways. They may be utilised,
with modifications of secondary importance, either with limited currents or with
continuous currents, for the transmission of signals, according to this invention,
by reversals of poles.
In order not to describe too many examples, only the method with continuous
currents will be indicated.
Fig. 21 shows a line y with a strengthening relay shunted at S.
The relay has differential winding, but the shunt current passes both the cur-
rents in the same direction and the effects are added. The armature communi-
cates with the head of the differential system as well as a condensers of any
suitable construction, increasing the action of the line currents. The contact
screws communicate, one with a positive battery, and the other with a negative

page_text: battery. At S' there is a suitable resistance which, however, is optional in certain
cases. The position of the batteries of the relay is such that a positive line-
current places the armature on the contact of the battery of the same sign, a
negative line-current places the armature on the contact connected to the
negative battery.
It will be seen that in these conditions the current of the relay, of the same
sign as that in the line, stops the latter so to say in order to take its place on the
side nearer the receiving post.
If the line current goes, say, from towards y, the current from the relay,
under normal circumstances is blocked on the side of and goes to y.
Any current coming from the line passes through the two windings of the
relay in the direction indicated by the arrow, it is therefore necessary that the
local current of the strengthening relay should pass through the two circuits of
the latter without disturbing its working, but on the contrary, helping it when
required. This is attained by causing the current from the battery to divide
into two branches suitably determined by means of the resistance S¹ or the pro-
portion between the two windings.
The following is one of the most remarkable points about this relay. When the
transmitting post reverses its poles, the battery of the relay adds its action to that
of the corresponding one, and under this double impulse, the relay works well
and without hesitation.
The armature becoming connected with the battery of the same pole as that
of the corresponding one the battery of the relay becomes substituted for that of
the line in order to continue sending a current in the same direction as before.
The local current passing through the coil on the side opposite to the line, main-
tains the armature in its new position and so on.
This strengthening relay may have different forms, it may be even used, in
certain cases, at the heads of a line, in combination (in series or shunt) with one
of the methods of reception herein before described, according to requirements
of the apparatus used.
This apparatus could be used even on cables with condensers where it would
considerably increase the favorable action of the latter.
When regulated so that its armature will remain when attracted in either end
position, and arranged according to the electro-diamagnetic system, as shown in
Fig. 22 or arranged on the diagonal of an electro-diamagnetic bridge (Fig. 23), the
strengthening relay has no regulating device and is not influenced by earth
currents. It could therefore be used with advantage on long underground
lines, the numerous shunts which the method comprises, reducing the incon-
venience of the great capacity of the cables without dividing the line into sec-
tions as is done by the ordinary relays. It is useless to enumerate all the advan-
tages and different applications of apparatus possessing such properties.
Fig. 22 shows a relay arranged according to the electro-diamagnetic system.
The chief difference between this and Fig. 21 lies in the different methods of
coupling the circuits. The line currents pass through the two circuits in opposite
directions so that they have normally no influence. At the moment of the
reversal of the poles, the apparatus becomes operative owing to the unsymmetrical
action of the condensers combined with one or more coils with or without self-
induction. The double relay hereinbefore described may also be used; in this way
the inducting action of one circuit on the other is avoided, and the self-induction
of the second circuit better utilised.
Finally, it will be seen (Figs. 22 and 26) that it is always possible to arrange a
controlling receiver S¹ (at the transmission station) operated directly by the
reversal of the poles, or through the intermediary of a local relay.
Duplex Telegraphing-Duplex telegraphing, according to the present inven-
tion, is effected simply according to any of the methods at present in use, adapted
to suit the new system.
Different Applications.-Owing to certain important properties of the system

page_text: according to the present invention the chief of which is that it does not require
a regulating device and is not influenced by earth currents, its applications are
very numerous.
It is therefore unnecessary to enumerate them in detail, except one which
appears to be worthy of special notice. That is the possibility of constituting,
similarly to electric nets for lighting, general telegraphic nets which could be
aerial, but which might be preferably, underground, in order to be protected
against storms etc.
These nets would be probably placed in the hands of the state for transmitting
special messages simultaneously to a number of stations. But as a source of
revenue, they could be leased to or used by news agencies etc. for transmitting
press-notes to a large number of newspapers at once.
These messages would then be transmitted directly from the central office of
the agency to different provincial branch offices.
The control of the state could be always ensured by means of a receiver
branched on the line and placed in one of the Government offices. This control
would have for its principal purpose to render impossible transmission of secret
messages.
At the present time, with the progress accomplished in the manufacture of
underground cables and the always increasing desire for rapid information, this
creation of press-nets would appear to be opportune and valuable.
Apparatus. As is apparent from the preceding description, the present inven-
tion relates more to an improved method of telegraphing wherein existing
apparatas may be utilised thun to the creation of new apparatu", "o that, if neces-
sary, the apparatus actually in use may be employed for telegraphing according
to the new system.
As, however for the sake of simplicity and sometimes as improvements,
several modifications have been made in the ordinary apparatus, they may be
referred to as follows:-
On submarine cables receiving instruments of Lord Kelvin, Lauritzen and
other similar instruments may be used. without any other modification except
the necessary addition in order to employ them as relays. This needs no further
explanation.
The unifilar or bifilar suspension may also, sometimes be done away with and
the movable part be placed between fixed points or on very delicate knife-edges
when passing from the vertical into the horizontal position.
In order to impart to these receivers certain properties which will sometimes
be necessary they are modified to an extent so as to practically make of them
new apparatus.
1. In order to obtain a sensitive relay with the position of the armature in-
differently on one or the other contact-piece, a movable galvano-metric frame
with a light needle of soft iron is placed in the field of a powerful magnet or
electro-magnet of any shape and size, so that the needle should be normal to
the plane of the windings.
The zero-position is adjusted by means of a light contact-lever oscillating
between two contact-screws.
This relay with the needle normal to the line of its poles is just the reverse of
the Marcel Duprez galvanometer.
In the present apparatus the needle or movable part is magnetised by the
current and deflected by the magnet. In the Marcel Duprez galvanometer, the
needle or movable part is magnetized by the magnet and deflected by the current.
The present apparatus may be adjusted so as to remain on the contact to which
it is attracted, for the purpose in view. In the Marcel Duprez apparatus the
movable part or needle is, on the contrary, strongly directed.
Finally, in the system according to the present invention, the frame may be
fixed and independent of the needle or movable part, or secured to it and

page_text: participating in its motion. In this case the electro-magnetic and the electro-
dynamic actions support each other.
In order to convert this apparatus into a relay with intermediate position, it
is sufficient to arrange one or several needles of the movable part normally to the
others, that is to say in the direction of the magnetic poles, and the movable part
always returns into a fixed position after having been deflected.
It will be seen besides that the system of directing or controlling is applicable
even in case when the motive movable part is done away with. The movable
part, of course will be supported between points or on knife-edges. It is useless
to describe these details which are well known to all electricians.
For underground or aerial lines and different local combinations herein before
described, a pattern has been designed which combines great simplicity of con-
struction great sensitiveness and rapidity with a minimum of self-induction. Its
essential parts will be now fully described the minor constructional details being
the same in all the relays.
Referring to Fig. 24; it comprises (1) A magnet T, preferably of circular
shape or it may be of any other shape, with or without set-screws for varying
the space between the poles.
(2) A coil T¹ placed in the centre of the magnet and having in its centre the
armature T movable between points, or on knife-edges above the neutral line of
the magnet.
This armature oscillates between two insulated contact screws mounted on the
poles of the magnet or in any other way.
This relay, the dimensions of which may be any desired, will comprise two
chief kinds the simple and the double forms. The simple form has just been
described, the double form (Fig. 25) consists of two similar apparatus mounted
on the same foundation but having one contact-rod t in common. For this
purpose a rigid spindle carrying the two armatures and the contact-rod in the
centre, pivots between points as shown in Figure 25.
These two constructions of relays are both such that the armatures can remain
in any position.
In order to convert them into relays with an armature always returning into
the central position, it is sufficient to place the movable part under the influence
of a suitable spring or some magnetic device.
Finally, a relay. of a different pattern from the preceding one will be described,
the difference being that the core armature instead of oscillating in the coil, pivots
about its axis and carries either at one or at both ends, polar appendices the ends
of which move between the poles of 1, 2 or 4 magnets arranged for this purpose.
The passage of the current through the coil polarises the core and its polar
appendices. The sign of this magnetisation determines the direction of move-
ment.
This kind of relay can be arranged in various forms but Figs. 26 and 27
give a sufficiently clear idea of the construction.
It will be seen that the core w is in the centre of the coil W. and is movable
between joints and is provided with polar appendices to each oscillating between
the two poles of a magnet W₁.
'
For a relay with one magnet, the core is provided only with one polar appendix,
for a relay with two magnets it has two appendices, and so on.
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. A new system of telegraphy, more particularly for use on lines of great
electro-static capacity (whether submarine, underground or aerial) characterised
by the reversal of equal electro-static charges in cables with condensers interposed
at both ends, or by the reversal of the sign of continuous or limited currents of
any duration on aerial and underground lines connected to earth at both ends.

page_text: 2. For the purpose of transmitting signals of unequal length on submarine
cables with condensers interposed at both ends according to the system described,
the use of two polarised relays the coils of which are placed in the local circuit
of the transmitting apparatus which also comprises a condenser, or in the secon-
dary circuit of an induction coil, the primary circuit of which comprises the
transmitting apparatus, the armatures and the contact-screws for the position
of rest being in the line circuit, while one of the contact-screws for the working
position is connected to a positive, and the other to a negative battery, the function
of said relays (or it may be a single relay the armature of which always returns
into the central position) being to transform currents of unequal duration sent by 1
the transmitting apparatus, into the short and equal currents in the line, sub-
stantially as described.
3. For transmission of signals under the conditions specified in Claim 2, the
use of two polarised relays, the coils of which as well as the transmitting
apparatus, are placed in the line circuit with or without a condenser, according
as the coils are placed in shunt on the line, or in series on it, the armatures com-
municating with the contact-pieces (for rest and work) of the transmitting
apparatus, the contact-screws serving for work being respectively connected to
positive and negative batteries, and the contact-screws for rest being insulated,
substantially as described.
4. For telegraphing with Baudot apparatus according to the method described,
the combination with each key of the key-board, of three local polarised relays,
the armature of the first of which is connected to the sector of the distributor,
corresponding to the key, and its contact screws respectively connected to the
armatures of two of the relays corresponding to the preceding key, the working
contact screw of the second relay being connected to a negative battery and that
of the third relay to a positive battery, while the contact screws of the second and
third relays, corresponding to their position of rest, are insulated, the coils of
all the three relays being placed in series with the local circuit of the key, sub-
stantially as described.
5. For the transmission of signals of equal duration according to the system
described the use of a polarised relay with an armature remaining in either end
position, the contact-studs of which relay are connected one to a positive and the
other to a negative battery, the armature terminating directly at the contact
corresponding to the working position of the operating lever, or being arranged
in the primary circuit of an induction-coil terminating at the contact corre-
sponding to the working position of the operating lever, the coil of the relay
being placed in shunt on the line and connected to a condenser or being placed
in the secondary circuit of an induction coil, substantially as described.
6. For the reception of signals transmitted in accordance with the system
described, a relay with an armature always returning into a central position,
placed directly on the line, or actuated by a local current of a reception relay,
said relay, having its contact screws connected to the receiving instrument and
its armature connected to a local battery, a condenser being placed in the circuit
of the coil of said relay, substantially as described.
7. For the reception of signals sent according to the system described the com-
bination of condensers and coils with self-induction for the purpose described,
particularly an electro-diamagnetic bridge in the diagonal of which is placed the
coil of a relay or receiving instruments, the four proportional branches being
constituted by resistances, the two opposite ones of which are with self-induction
and the remaining two without, the latter being shunted by condensers sub-
stantially as described.
8. In apparatus for carrying out the electric telegraphic system described a
strengthening relay applicable for long land lines, the coil of which, with dif
ferential winding, is always in shunt on the line, either directly or in the diagonal
of an electro-diamagnetic bridge and the contact-screws of which are respectively
connected to positive and negative batteries, the armature of the relay being

page_text: connected if desired, either to the head of the differential winding connected to
a condenser, in which case a resistance is placed at the issue of the coil, or at the
issue of the coil a resistance being interposed, the head of the differential winding
always remaining connected to a condenser, substantially as described.
9. For carrying out the invention described in which signals of unequal
duration are employed the combination and arrangement of parts substantially
as and for the purpose described and diagrammatically illustrated in Figure 1 or
in Figure 2 or in Figure 3, or in Figure 4 or in Figure 5 or in Figure 6 or in
Figure 7 or in Figure 8 of the accompanying drawings.
10. For carrying out the invention described in which regular signals with
unequal intervals are transmitted and received the combination and arrangement
of parts substantially as and for the purpose_described and diagrammatically
illustrated in Figure 10 or in Figure 11 or in Figure 12 or in Figure 13 of the
accompanying drawings.
11. For carrying out the invention described, the combination and arrange-
ment of parts constituting relay apparatus operated by reversals and not subject
to influence by continuous currents, substantially as described and illustrated in
Figure 14 or in Figure 15 or in Figure 16 of the accompanying drawings.
12. For carrying out the invention described the combination and arrangement
of parts constituting the combined relay apparatus substantially as described
and illustrated in Figure 17 or in Figure 18 or in Figure 19 or in Figure 20 of
the accompanying drawings.
13. For carrying out the invention described, the combination and arrange-
ment of parts constituting the relay apparatus for long distance lines substantially
as described and illustrated in Figure 21, or in Figure 22 or in Figure 23 of
the accompanying drawings.
14. For carrying out the invention described the combination and arrange-
ment of parts constituting the relay device substantially as described and illus-
trated in Figure 24 or in Figure 25 or in Figures 26 and 27 of the accompanying
drawings.
Dated this 12th day of October 1898
BOULT & WADE,
Agents for the Applicant.