Improvements in or connected with Telegraphy and Telephony, and' in Electric Relays for Use therewith.
Year: 1895

page_text: Date of Application, 11th Nov., 1895
Complete Specification Left, 11th Aug., 1896-Accepted, 31st Oct., 1895
PROVISIONAL SPECIFICATION.
Improvements in or connected with Telegraphy and Telephony, and'
in Electric Relays for Use therewith.
We, ERNEST JULES PIERRE MERCADIER and HENRI ROBERT JOSEPH
PIERQUIN, Fils both of 16, Rue Drouot, Paris, in the Republic of France,
Electricians, do hereby declare the nature of this invention to be as follows:-
Multiple telegraphs which are based the same as harmonic telegraphs on the
employment of alternating or undulatory currents, bave up to the present been
difficult of practical management; and this circumstance was especially due to the
fact that all transmitting and receiving instruments were both inserted in the line
circuit. There resulted from such a state of things an electrical resistance and
self-induction, which reached a high degree in comparison with similar phenomenȧ
on the line.
The system which we claim as our invention, was devised in order to insert in the
line circuit of every station only one microphone relay and one induction coil, in
connection with certain other hereinafter described instruments.
The microphone relay must necessarily be very sensitive, in order to transmit to
the receiving apparatus electrical waves coming from a line of great length and
high capacity. It is composed of a wood base on which the microphone relay
proper is secured by angle-irons or in other suitable manner. By means of an
adjusting screw which protrudes through said base and whose point rests in the
bottom of a socket, the apparatus may be more or less inclined. Our microphone
relay is composed of an ordinary telephone, on whose coils are wound two parallel
wires; and on the diaphragm of the same telephone is fixed a carbon disc. In
front of said carbon disc, is another carbon contact carried by a spring arm
This arm is formed of a flat and
suspended from the upper part of the instrument.
very thin spring provided at its lower end with a certain weight so as to form a
kind of spring pendulum, the carbon contact being attached to the weight. This
pendulum is electrically insulated from the other parts of the apparatus by means
of ebonite sheets and washers at its point of suspension.
In order to avoid the effects of exterior vibrations on the relay, it is placed on a
small board which rests on india-rubber tubes lying on the table, the relay being
supported on said small board by means of india-rubber tubes at one end and by the
before mentioned adjusting screw at its other end.
One of the convolutions of the relay coil or coils is inserted in the actual line
circuit, and the other one in the artificial liue circuit.
By an adjustment which is effected by means of the screw, we obtain a micro-
phonic contact which, being made as sensitive as desired gives very intense effects,
because the pendulum remains nearly unmoved, while the relay diaphragm is
vibrating under the influence of the currents.
This apparatus has given us better results than any other of the numerous,
systems which we have tried.
The relay's microphonical contact is inserted with a battery in the primary
circuit of an induction coil and the secondary wire of this coil operates the receiving
instruments.

page_text: An induction coil having a thick-wired primary circuit with a thin secondary
circuit is suitably arranged; and in the secondary circuit there is shunted a
subdivided condenser, that is to say a condenser of which the capacity may be
varied. The primary circuit is fed by one or more sources of current, and said
source or sources are produced by special instruments, such as electrical tuning
forks for instance.
The relay has been devised very sensitive, in order that it may be operated by
line currents; but in order to obtain a practical result, the relay must remain
immovable under the impact of currents which are sent out of its own station. In
order to obtain such a result, we make use, in connection with the above described
induction coil, of another induction coil which is similar thereto, that is to say
which is provided with a thick wired primary circuit and a thin wired secondary
one; and in the secondary circuit of which a subdivided condenser is inserted, of
which tho capacity may be varied at will. Both primary wires of these two
induction coils are connected up in series, and fed together with the current
impulses produced by the transmitters.. The secondary wire of the line induction
coil is inserted in the actual line circuit together with a convolution of the electro-
magnet coil which forms part of the microphone relay; and the secondary wire of
the extinguishing induction coil, is inserted in the artificial line circuit together
with the other convolution of the relay coil.
Then, as several currents are sent out simultaneously, the microphone relay
remains immovable under their impact, but it is absolutely necessary, in order to
attain such a result, that the relation between the capacities of the condensers be
conveniently adjusted.. Such an adjustment is requisite, because the alternating or
undulatory currents are reaching the relay coil at the same time, with contrary
directions and equal intensities, and in the same phase of their respective
motions.
We have given to both condensers the name of extinguishing condensers,
because it is only by their attaining a mutual equilibrium that we are able to annul
the action, on the microphone relay of a station, of currents sent out of the same
station. It is to be noted that both parallel convolutions of the relay coil or coils
differ from the differential convolution employed up to the present in duplex
systems for ordinary currents. In the usual duplex arrangements. both differential
convolutions, have a common point, of connection, while in our system both
convolutions are electrically insulated one from the other.
Our system is of course alike applicable to a double line or to a simple one which
is provided with earth-connectious, at each end.,
The system is applicable to, multiplex telegraphy, whether all the telegraphio
instruments (whatever may be their number) be located at both extremities of the
line, or scattered over several points along the line.
The system. is also applicable to call systems, whether the call instruments
be located at both ends of the line or scattered over several points along the
line.
The system is moreover applicable to all telephone offices where by using very
powerful transmitters it is intended to obtain silence in the telephones of the
speaking office, and in that case these telephones are operated only by the currents
coming. from the corresponding telephone office.
The combination of induction coils with adjustable condensers, may be used in
simultaneous telegraph and telephone working, whether the service be made by
means of transformers or self-induction coils or by separating condensers, in order
either to diminish or to suppress thoroughly the crackling sound which is produced
in telephone offices by telegraphic transmissions; for instance, if the above
described system. is to be applied to a simultaneously-working telegraph and
telephone system by means of transformers, the induction-coils or transformers
which are to be added to the system and the extinguishing condensers are so
placed that by a convenient adjustment of the extinguishing condensers it is possible

page_text: to suppress the crackling sounds which are produced in the telephone station by the
sending out of currents from the telegraph office.
Dated this 8th day of November 1895.
WM. P. THOMPSON & Co.,
Of 6 Lord Street, Liverpool, Agents for the Applicants.
Improvements in or connected with Telegraphy and Telephony, and
in Electric Relays for Use therewith.
We, ERNEST JULES PIERRE MERCADIER and HENRI ROBERT JOSEPH
PIERQUIN Fils, both of 16 Rue Drouot, Paris in the Republic of France
Electriciaus, 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 :-
This system is intended to place simultaneously in relation, as is shown as an
example in Figure 1, of the accompanying drawings-
1st. A telephonic or telegraphic line L having double wires or a single wire, and
earth plates at both ends;
2nd. A transmitting circuit C, where there are produced by any suitable
means one or more systems of alternating or undulatory currents of different periods
or frequencies.
3rd. A receiving circuit C containing apparatus R° capable of receiving the
currents, of which mention has just been made, and utilizing them for telegraphy,
telephony, or the like.
4th. An extinguishing or equilibrating circuit Co.
A. The relation of the line with the transmitting circuit is established by means
of the secondary wire of an induction coil B' (line induction coil) and of a wire¹
wound on a core n of the electro-magnet of a telephone forming, part of an
apparatus Rhereinafter described.
B. The relation of the line with the extinguishing or equilibrating circuit is
formed by means of the secondary wire 2 of another induction coil B (extinguishing
coil) identical with the former coil B', and of a second wire fe absolutely identical
with the wire and wound on the same core n, and, of an artificial line L
formed of resistances and graduated condensers, intended to contribute to the
extinguishing in the circuit C of the effects of currents transmitted on the
line L, as will be hereafter stated in paragraph III.
C. The relation of the line with the receiving circuit is established by means
of a differential telemicrophonic relay R and of the secondary wire 2 of the
induction coil Br.
The relay is formed as shown diagramatically in Figure 1, of the accompanying
drawing, and in elevation in Figure 2;
1st. Of a telephone of which d is the diaphragm and n the core of the electro-
magnet on which are wound two identical wires ffe capable of being traversed. in
opposite directions by currents arising from the same source, and
P
2ndly. Of a microphone composed of a disc or plate of carbon screwed on the
diaphragm d, a contact c of carbon fixed to a metallic mass m supported by a flat
and thin spring r fixed to the framework of the telephone and insulated from the
apparatus by a plate of ebonite O, the length of which spring may be varied.
A screw V allows of the coils 6 being approached to the diaphragm d of the
telephone.
Two angle pieces E El fix the telephone on a support S S¹ which has on one
side a thick india-rubber tube & resting on two other tubes t t placed side by side

page_text: Finally the line L, Figure 3, may connect two ports or stations containing the
series of apparatus which have just been described and each of them may transmit
simultaneously or otherwise in a circuit identical alternating or undulating
currents received in the other station, by means of this line L.
WORKING OF THE SYSTEM.
This system fulfils a triple function (Figure 1).
I. The system is a collector of alternating or undulatory currents arriving by
the line, for their energy in passing through the wire is transformed into
mechanical energy in the diaphragmnd of the telephone, the molecules of which
vibrate synchronically with all these currents, reproducing without alteration their
periods or frequencies. The system may be at the same time a collector of
currents of the same Dature as those of the line produced in the transmitting
circuit C, and which arrive simultaneously at the telephone of the relay R in an
inverse direction by means of the two coils B B and the two coils of the wires fƒ°.
This point will be referred to again in paragraph III.
II. The system is an automatic distributor in the receiving circuit C of currents
arriving from the line L because the vibratory movements which these currents
produce in the diaphragmrd of the telephone are transmitted without alteration of
frequencies to the microphonic contact p c and are reproduced by means of a
primary wire 1, by induction, in the secondary wire of the relay coil B in the
receiving circuit C.
It will be hereafter shown (in paragraph III) that the currents produced in
the transmitting circuit Ct, and which may also arrive in the wire of the relay
do not produce any effect in the receiving circuit C
III. The system is an extinguisher in the relay R of currents produced in the
circuit transmitter of the station where this relay is located.
In fact these currents arrive simultaneously by the two coils B' Bº and in an
inverse direction, in the wires fe of the relay; they have also the same frequencies
and they may be given the same phase by causing the relation of the capacities of
the graduated condensers C' Ce to be varied, and the artificial line Le of graduated
resistance aud condensation, because action is obtained by means of them on the
self induction of the coils B' Be; this new result is of capital importance in this
system.
These currents arrive therefore simultaneously in the relays in an inverse
direction, with the same frequency and the same phase, they have no action on the
relay, and they are therefore extinguished in this relay, whilst they are propagated
freely in the line L.
Experience has proved that this result may be easily obtained by manipulating
the condensers C' Co. It must be noted also that the arrangement herein before
described will also be applicable, if in place of employing a differential winding on
the relay or telephone, the latter be provided with a single wire in the manner of a
"Wheatstone" bridge between the cireuit of the real linc, and the circuit of the
artificial line.

page_text: APPLICATION OF THE SYSTEM.
This system is equally well applicable to every system of duplex telegraphy where
ordinary currents are used and to all systems of telegraphy founded on the use of
alternating or undulatory currents. For instance, it is. immediately applicable to
the system of multiplex telegraphy described in Patents Nos. 10363 of July 17th
1888, and No. 13322 of August 23rd 1889.
As a second example it allows of their being effected a double particular
telephonic transmission simultaneously in an opposite direction. It is sufficient for
this purpose in two stations A and E to place in the transmitting circuit Ca
telephonic transmitter (any suitable telephone or microphone) and in the receiving
circuit Ca telephonic receiver, it is thus seen that station A can telephone to
station B which will receive the message in its receiver and at the same time B.
can telephone to A which will receive the message in its receiver and vice versa..
It may be employed for producing distinct or separate multiple calls capable
of crossing with suitable receivers (of monotelephones for instance) all placed
at the end of a line, or distributed in stations along this line, like the stations of
a railway for example.
It allows of telephony being used on wires which serve at the same time as
means for conveying energy by alternating electric currents, of course employing
suitable bobbins or coils, relays and calls.
The combination of induction coils and graduated condensers shown in the
arrangement bereinbefore described may be used in systems of simultaneous
telegraphy and telephony, in order to diminish, or cause to disappear, the noise of
crackling produced in telephone stations by the transmissions of telegraph stations,
no matter what system of transformers be employed (such as Picard's system) or
self induction coils (Cailho, Jacob, Dejough, or the like) or separating
condensers.
Figure 4 shows as an example the arrangement employed where the system in
question is used with a system of telegraphy T and telephony simultaneously
obtained by means of transformers F' F2. The coils or transformers B' B' to be
added are placed as shown in the figure and the condenser, extinguishers or
equilibrators are at C¹ C³.
The forms, dimensions, proportions and accessory parts may be of course
varied and any materials which are deemed suitable may be used for their
construction.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
1. In a system for the collection, distribution and automatic extinction of
undulatory or alternating electric currents, the use of a telemicrophonic relay
composed of a telephone having a coil or bobbin with two differential windings and
of a microphone having a single contact in the form of a pendulum with an elastiv
rod, substantially as herein before described.
2. In combination with the herein described relay, the use of two induction coils
or transformers, the primary wires of which are arranged in series and the
secondary wires of which have arranged in shunt graduated extinguishing
condensers for rendering the tele-microphonic relay or the telephonic station
insensible to alternating or undulatory currents produced in a transmitting circuit,
by causing the phase of these currents to vary, substantially as hereinbefore
described.
3. In combination with the herein described relay, the coils and the condensors,
the use of an artificial line composed of resistances and condensors suitably grouped
or arranged on Muirhead's system, intended to be placed in the extinguishing coil
of the relay, substantially as herein before described.

page_text: 4. The application of the whole or part of the combination hereinbefore described
to multiple and multiplex telegraphs whether the stations, which may be of any
desired number, be placed at the two ends of the line or distributed at different
points of the said liue; also to multiple calls under the same conditions; to
subscribers or other telephone stations; to telephony on a circuit for transmitting
energy by alternating currents; to duplex telephony; to various systems of
simultaneous telegraphy and telephony; and in general all other applications which
may be made of the system.
Dated this 10th day of August 1896.
W. P. THOMPSON`& Co.,
Of 6, Lord Street, Liverpool, Agents for the Applicants.