IMPROVEMENTS IN TELEPHONIC APPARATUS
Year: 1883

page_text: LETTERS PATENT to Edgar George, Francis Agnew Pocock, John Saunders
Muir and John Saunders Muir junior all of St Stephens Chambers in the
COMPLETE SPECIFICATION filed by the said Edgar George, Francis Agnew
Pocock, John Saunders Muir and John Saunders Muir, Junior at the Office
of the Commissioners of Patents on the 2nd October 1883.
EDGAR GEORGE, FRANCIS AGNEW POCOCK, JOHN SAUNDERS MUIR, and JOHN
SAUNDERS MUIR junior all of St Stephens Chambers in the City of London
IMPROVEMENTS IN TELEPHONIC APPARATUS
The object of our invention is to provide efficient means for the transmission of
telephonic signals over considerable lengths of wire which transmission has hitherto
been found impracticable owing to the amount of retardation and induction that
have always been found in these cases.
To carry out this object we have designed a relay which with the necessary
batteries are placed at convenient distances along the line of route and preferably
on a closed circuit that is a circuit on which there is a constant current of electricity
traversing the line throughout its length. During the time the circuit is thus
closed the telephonic relays are cut out of the circuit but upon opening the circuit
the bell at the distant end will ring a warning and when the receiver is removed
from a suitable switch the telephonic relays at each station are open to receive the
signals and by the aid of the local batteries retransmit these signals to the terminal
station. By the adoption of this method we overcome to a great extent those
drawbacks to long distance telephony hereinbefore mentioned namely retardation
and induction.
The relay is constructed by combining an electro magnetic or other receiver of
any suitable form such for instance as those which are commonly known by the
names of Bell or Ader with a microphonic or other transmitter of any suitable form
such for instance as those which are commonly known by the names of Edison or
Blake or Theiler We can also use with special advantage the receivers and

page_text: transmitters which we described in the Complete Specification of our Patent
No. 4298 of 1883 which we filed in the Great Seal Patent Office on the seventh
day of September one thousand eight hundred and eighty three. These said
receivers and transmitters are extremely suitable for our purposes as herein
described. The receivers and transmitters are combined in such a manner that
there is constituted a mechanical or material contact between the same so that the
vibrations received by the receiver are coinmunicated to the transmitter and thereby
forwarded. According to another form of our apparatus we produce this same
aforesaid effect by induced magnetism instead of by contact..
In order to clearly explain our invention and the manner in which we carry out
our aforesaid object we refer to the accompanying drawing in Figures 1 and 2 of
which we shew two forms of the telephonic relays we propose to use.
In Figure 1A is a ring or frame of metal or vulcanite across which are tightly
stretched the wires or strips B B¹ and B¹¹ which wires or strips are made of any
metal or material that is incapable of inductive action. In the middle of the wire B
is fixed a platinum head or pellet C which presses gently against the carbon disc or
plate D which disc or plate is secured on the wire B¹. On the back of the carbon
disc or plate D at or near the centre thereof is fastened a short stud E of wood
vulcanite ivory metal or other suitable material. On the wire B¹¹ is fixed a helix
of insulated wire F in the centre of which and securely attached thereto is an
elongated core of soft iron F¹ the end of which core F¹ presses gently against the
stud E. Two other helices of insulated wire F1 and F¹ surround the core F¹ one
of the said helices being on either side of the helix F and the said helices Fil
and Fare rigidly fixed on the case or elsewhere while the core F can move
freely within them. Thus when the vibrations are set up in these helices which
constitute the receiver by the variations of the current the core F' presses with
greater or less force against the carbon disc or plate D through the mechanical
or material intervention of the stud E and these said vibrations are thereby
communicated to the transmitter and by it forwarded.
In Figure 2 A is the ring or frame across which are stretched the wires B B¹
and B as herein before described. In the middle of the wire B is the pellet C
which presses gently against the carbon disc or plate D the back of which disc or
plate carries the stud E as hereinbefore described. The stud Ę presses gently
against a plate or disc of soft iron G which plate or disc is secured to the wire B
Behind the plate or disc G and in close proximity thereto is the helix of insulated
wire H mounted on the core of soft iron H' which core is attached to the permanent
magnet I secured on the frame or elsewhere. The action in this form is similar to
that herein before described namely that the vibrations set up in the plate G are
mechanically communicated to the transmitter through the intervention of the
stud E.
A modification of this form consists in dispensing with the wire B" and the
stud E and connecting the plate G to the back of the carbon disc D. In this
case also the desired effect is produced by a material contact between the receiver
and the transmitter or between parts of the same.
In this form as shewn in Figure 2 we can also produce the aforesaid desired
effect by induced magnetism. According to this method we dispense with the
stud E and instead thereof fix on the back of the disc or plate of carbon D another
plate of soft iron which faces the plate G before described. The magnetism
induced in the plate G by the varying magnetism of the helix H will simul-
taneously produce corresponding varying magnetism in the plate on the back of
the disc D causing the said disc D to vibrate.
We have thus shewn two forms of our apparatus in both of which the trans-
mitter is made in accordance with one of the instruments as described in our
former Specification herein before mentioned but in illustrating these forms as
.aforesaid we would have it clearly understood that we do not in any wise limit or
confine ourselves to these forms as shewn or to any other particular form but that
we may apply our invention to any telephonic system. For instance it can be

page_text: applied to a combination of the Blake transmitter and the Bell telephone by
placing the said telephone arrangement in close proximity to the diaphragm of the
said transmitter and interposing between the same a stud or other mechanical
appliance or by making a material contact between the same thus causing the
vibrations set up in the diaphragm of the receiver by the action of the variable
currents received from the distant end to reproduce by mechanical or material
means corresponding vibrations in the microphonic transmitter. In the same
manner we can treat any other telephonic system.
Figure 3 illustrates a method of arranging the necessary connections at a relay
station to enable us to use our apparatus with a current coming each way.
L is the electro magnetic relay. O and O¹ are the telephonic relays. MB is
the line battery. LB are the local telephonic relay batteries. PS and P'S¹ are
the inductoriums.
A current arriving from Line 1 passes through the helices of the electro magnetic
relay L traverses the armature M and passes through the contact post N to Line 2
putting in circuit the battery M B. When the circuit is broken the armature M is
released from its position as shewn in the drawing and presses to the right either
by the aid of a suitable spring or if a polarized relay is used by magnetic attraction.
The armature M thus pushes forward the forks X X and makes a connection with
the contact posts 1. 2. 3. 4. 5 and 6 and the speaking current flows as follows.
Passing from Line 1 through the helices of the electro magnetic relay L to contact
post 1 the said current flows through the fork to contact post 2 thence through
the secondary S₁ of the inductorium to the helix O and to Earth. The trans-
mitter R of this telephonic relay is therefore put in action and the local battery
forms a circuit thus. From the contact post 2 through the primary P of the
inductorium thence through the transmitter R to Z K of the local battery and
finally to contact post 3 thus completing the circuit through the fork. The
secondary circuit thereby induced passes from Earth through the secondary S of the
inductorium to the helix O' and thence to contact post 5 through the fork to contact
post 6 whence it passes along Line 2 to the instrument at the next station.
Currents coming the other way from Line 2 follow this course. Passing froin
Line 2 to contact post 6 the said current flows through the fo:k to contact post 5
thence through the helix O' to Earth through the secondary S of the inductorium.
The transmitter T of this telephonic relay is therefore put in action and the local
battery forms a circuit thus. From the contact post 4 through the primary P¹
of the inductorium thence through the transmitter T to Z'K' of the local battery
and finally to contact post 3 thus completing the circuit through the fork. The
secondary circuit thereby induced passes from Earth through the helix O to the
secondary S¹ of the inductorium and thence to contact post 2 through the fork
to contact post 1 whence it passes through the helices of the electro magnetic'
relay Lulong Line 1 to the instrument at the next station.
We have thus shewn a very good method of arranging the connections for the
purpose of using our apparatus but any other suitable and convenient method
may also be used as may be desirable in each case.
Having thus particularly described and clearly explained our invention and in
what manner the saine is to be performed and used we claim as our invention
1. The stud or other projection hereinbefore described by the use of which
mechanical or material contact is obtained between the receiver and the trans-
mitter and the vibrations received and set up in the receiver are reproduced in the
transmitter substantially as and for the purpose herein before described and set
forth.
2. The making a material contact between the diaphragm or disc of the receiver
and the microphonic or electro magnetic transmitter whereby the vibrations
received and set up in the receiver are reproduced in the transmitter substantially
as and for the purpose hereinbefore described and set forth.
3. The relay formed by the combination of an electro magnetic or other
telephonic receiver and a microphonic or electro magnetic transmitter by which

page_text: the vibrations set up in the diaphragm or iron disc or plate of the receiver are
transmitted by contact or otherwise to the transmitter substantially as and for the
purpose herein before described and set forth.
4. The relay formed by the combination of an electro magnetic or other
telephonic receiver and a microphonic or electro magnetic transmitter as herein-
before described and claimed in conjunction with an electro magnetic relay by
which the circuit is closed or opened automatically substantially as hereinbefore
described and set forth.
5. The general arrangements as herein before described and shewn by means
of which electrical impulses or vibrations which are set up at the starting station
can be automatically retransmitted to considerable distances and delivered at the
receiving station substantially as hereinbefore described and set forth.
In witness whereof we the said Edgar George, Francis Agnew Pocock, John
Saunders Muir, and John Saunders Muir junior have hereunto set our hands and
seals this first day of October in the year of our Lord one thousand eight hundred
and eighty three.
EDGAR GEORGE
FRANCIS. AGNEW. POCOCK.
JOHN SAUNDERS MUIR
(LS.)
(L.S.)
(L.S.)
JOHN SAUNDERS MUIR JUNIOR (L.S.)