IMPROVE- MENTS IN APPARATUS EMPLOYED FOR AND IN TELEGRAPHIC OR TELEPHONIC COMMUNICATION
Year: 1881

page_text: LETTERS PATENT to Philip Middleton Justice, of 14, Southampton Buildings,
in the County of Middlesex, Patent Agent, for an Invention of "IMPROVE-
MENTS IN APPARATUS EMPLOYED FOR AND IN TELEGRAPHIC OR TELEPHONIC
COMMUNICATION." A communication from abroad by Jacques Victor Michel
Bartelous, of Brussels, in the Kingdom of Belgium.
PROVISIONAL SPECIFICATION left by the said Philip Middleton Justice
at the Office of the Commissioners of Patents on the 11th February 1881.
i
PHILIP MIDDLETON JUSTICE, of 14, Southampton Buildings, in the County
of Middlesex, Patent Agent. "IMPROVEMENTS IN APPARATUS EMPLOYED FOR
AND IN TELEGRAPHIC OR TELEPHONIC COMMUNICATION." A communication from
abroad by Jacques Victor Michel Bartelous, of Brussels, in the Kingdom of
Belgium.
The first series of apparatus permits the establishment on a system of three wires
of an unlimited number of subscription stations or telegraphic offices, giving to each
the right of calling a central office. By the help of this office the different stations
can be put in communication with each other or with other lines, For the time
being all communication on the system is stopped except between the "caller" and
the "called." If it is wished to limit the enquiries and communications on the
system the number of wires can be reduced to two, but the system of three wires,
has this advantage, that during the communication of a 'caller" a wire remains
free either to put this subscriber in communication with another subscriber on the
same system, or to call all the subscribers or the offices, including that already at
work, to put them in communication with another enquirer. The second series of
apparatus refers to the installation at any required distance from a central office of
an instrument, which may be called a distance commutator, and which does away
with the necessity of the establishment of an auxiliary office, substituting therefor.
an automatic station. .
Around this apparatus and connected to the central office by a system of two or
three wires any number of telephonic subscribers or telegraphic offices can be con-
nected. Assuming the existence of a system of three wires, in this case the system
described permits,―
1st. Each subscriber or each office to call the central office, and to be put by

page_text: that into communication with any telephonic or telegraphic apparatus on the
system.
2nd. The central office to call any subscriber or any office of a group at will
without producing a call on another, and to communicate anything it may
desire.
3. It permits two subscribers in the same group at a distance from each other to
be put into communication by the electrical working of the apparatus of the
automatic post.
When the service described in paragraph 3 is not in use, or when it is wished to
reduce the system to two wires, and the construction of the distance commutator to
one dial plate only, this apparatus would then undergo important simplification.
Reserving to myself the subject of the complete or modified application of the
system, I shall have occasion in developing this Specification to refer to some
modifications resulting from the reduction from the one or the other system to two
wires, and explain various apparatus, such as commutators, galvano-meters, &c., in
use at the central office or at the subscribers, to facilitate the working of the currents
or to insure the privacy of the communications. I conclude these general remarks
by saying that the following description treats of a supposed installation of a system
of three wires applied to a telephone working, at the same time expressly claiming
the use of similar apparatus for telegraphic working.
The subscriber No. 3 C called by the central office, by putting the discs in position
where the needle of this subscriber is in contact, has been put in communication
with No. 2 B, who has asked for him. No other subscriber on this system can have
communication, thus ensuring the secrecy of the conversation.

page_text: junction of the wires of the line and of the return is made on the one commutator
of the system.
The plant at the central office includes for each system a circular commutator
divided into two parts, each furnished with a working needle. The wire of the line
is jointed at the central part of the rotation of the upper needle, and the extremity
of the return wire to the central point of rotation of the lower needle. Each of
these wires passes (before arriving at the, commutator) through a telephone with a
bell, which can be admitted in the current or a galvanometer on current at will.
On leaving the commutator the wire of the line when at rest is connected with the
soil, whilst the return wire is isolated and eventually is placed in communication
with a battery or an electro-machine. The working wire is also in communi-
cation with a battery by the aid of a Morse key, and before leaving the office
the currents which are sent pass through the mechanism of a dial apparatus on
which they move a needle. The system A. being at rest, it is seen that every current
from a battery or from an electro magnetic machine sent from any subscriber's
station will act on the bell of the wire of the line in the office. But in order for a
subscriber to be enabled to despatch this current he must first perform certain
movements with his apparatus, which will be hereinafter set forth. In addition to
the apparatus actually in use, the plant at each subscriber's must include a box
containing an electro magnet governed by the working wire of the system. The
current sent at will from the central office passes through the wire, acts on the
electro magnets by causing a lever to oscillate, which governs a double toothed cog
wheel so arranged that each movement of the lever causes the wheel to advance one
tooth only. This movement of the wheel causes the rotation of the disc, presenting
a semi circular notch to its circumference, across which when the disc is in a position
of repose a plate terminating in a shank of a button passes freely. As soon as the
disc is in its place the passage of the current is no longer possible. The pressure of
the button causes the call bell to be rung by means of the wire of the line; this is
effected by the current of the battery or of the electro magnetic machine arriving
by the conductor fixed on the front of the box passing through the arm of a rod,
the conductor, the bell (and later the telephone when that is unhooked), and finally
through a second conductor, the extremity of which is in communication with a
metal cylinder, in which works the shank of the button before referred to. When
the button is at rest the current is stopped at this point, but as soon as the button
is pushed in the plate comes in contact with a spring terminating the wire of
the line, which is joined in the apparatus to the conductor, the spring of
which when at rest being in contact with the metal cap surrounding
the disc, whilst it breaks this contact when the button is pushed in, which
causes it to take another position. Suppose a call be sent to the central
office; as soon as it is produced four successive emissions of the current are sent
through the working wire; this has the effect of causing the toothed wheel to
advance four divisions, that is to say, one twelfth part of the circumference. This
effect is produced in all the apparatus, causing the discs to advance one twelfth
part of their circumference, and preventing any other subscriber from pressing in
his button to effect communication. Besides he will be informed of this fact by a
special arrangement formed as follows:-The discs are painted in two distinctive
colors, such as red and blue; the greater part of the surface is red, except a sector
of a twelfth part of the circumference, of which the lower radius is horizontal, and
which is painted blue. The portion of the front face of the box corresponding to
this sector is colored in the same shade. It has the word "fermè " (or "closed")
on it cut out on a thin plate. So long as this blue sector is at the back of these
cut out letters the words will hardly be apparent, but when the disc turns, and the
red color shows through the cut out letters, the word will show out very plainly,
and the subscribers are thus informed that the system is in use. They have
however a means of applying for communication in their turn; this is afforded
them by the working of the rod before referred to. The discs are constructed of
non conducting material, with the exception of the metal cap and of the metallic
•

page_text: needle placed on the interior face. Supposing that on the circumference of the
discs there were a number of stopping points equal to half the number of teeth in
the notched wheels, it will be seen that the figures would represent 24. Of these
twenty four positions two are taken by the sector. The twenty two remaining
ones correspond by hypothesis to a number equal to the subscribers. Now the
needles are arranged so that each shall occupy a different position of projection;
in this case, where all the discs would be in contact, and where each of these
positions correspond to one of the divisions of the circumference and to a number
in rotation which corresponds to the subscriber's number on the point of the
circumference of the cap which corresponds to the extremity of the needle the cap
bears on the front of the disc internal projections, the object of which will be
explained. If one or more subscribers are placed in waiting position during an
exchange of conversation, the following fact occurs:-The conversation ended, a
successive emission of currents sent by the central office through the working wire
sets all the discs in rotation so as to bring them back to the point of rest. During
this movement the projections of the caps successively and in numerical order pass
under the extremity of the spring. If the rod is lowered, that is to say, if the
button is detached, this passage will produce no effect, but if on the contrary the
rod be lifted, as before explained, the current of the battery will be connected with
the button and the spring by means of the said lever. At the moment of its
passage past the projection the current passes to the metal cap. Now I have
already said that when the button is not pushed in the spring terminating the
conductor of the wire of the line is in contact with the metal cap. From that
time during the rotation of the discs each time a projection meets a spring in
communication with the subscriber's battery, it will cause a current which will be
regulated and registered with the subscriber's number at the central office. It
must be observed that the current working the bell of the central office will not
act on that of the subscribers. At the first waiting call met with in this operation
the central office will reply by sending a current from its battery through the
return wire. This latter is connected with a piece fitted with a spring pushing
against the interior face of the disc. Whilst the projection meets the extremity of
the first spring the needle meets the extremity of this second spring. The needle is
in communication through the axis of the disc with the conductor, directing the
current into the ground through the bell; the subscriber thus informed will wait
the return of the disc to the resting point, the return to which will be signalled by
the disappearance of the word fermè (or closed) in red letters; then he can
push in his button to send his communication. The other waiting, calls noted by
the continued movement of the discs will be simply registered to take their
successive turns without the subscribers, being disturbed before their turn comes.
The explanations I have given as to the manner of informing the subscriber. who
has been called first will dispense with the necessity of explaining the way by
The dials of the apparatus
which a subscriber can be called by the central office.
at the central office serve to regulate the movement of the discs and to establish
the numerical order of the subscriber communicated with; their needles are worked
by batteries crossing the working wires, and regulated by the Morse keys. The
commutators, the conception and disposition of which I claim, can by a simple
rotary movement of the needle put the wires of a line of a series in communication
either with the return wire of another, or with the return wire of the same system,
or even permit the making or the cutting off of the communication of these same
wires with the battery or with the earth. It is sufficient for the subscriber who
has held his communication to slightly withdraw the button from the entire stroke
in order to relieve the plate from contact with the first spring, and without
hindering the rotation of the disc. This gentle removal of the button is used to
give notice to the central office of the close of the conversation. The currents of
communication pass to the central office by means of galvanometers, which signal
the existance or the suppression of the current. This permits of the end of a
conversation being signified without connexion with the office.

page_text: This relates to the distance commutator and second series of apparatus designed
for the purposes before referred to. As in the first series, I will describe the
apparatus employed when using a system of three wires. It is to be noted that
the distance commutators or automatic posts disconnect each of the auxiliary posts,
and the plant of the central office corresponds to the number of auxiliary posts, but
the number of points of contact to be placed on the commutators to be served by
the central office are undetermined. The distance commutator, as indicated by its
name, permits the changing at any distance of the direction of, an electric current
so as to bring it by a single wire to a given point, and to diverge it from this
point to an unlimited number of auxiliary stations, and vice versa. It consists of
two horizontal dials of similar size placed side by side, and of a third dial which is
smaller and placed parallel but below the main dials. The dials are constructed of
some non conducting material, and in their circumference have some metal pieces
or reserves, said reserves being connected by wires which join the wires of the line,
which are directed from the commutator towards the instruments of each sub-
scriber of the group. From each of these subscribers instruments a wire proceeds
which meets in proper order the points of the dial. The centres of the dials are
pierced by two vertical axis which receive their rotary movement by means of the
two cog wheels attached to the axles. These wheels are worked by the levers
attached to the stays of the two electro magnets. The axis is composed of two
metallic pieces separated by an isolating piece on which is supported the also
isolated central portion of the needle. Below this again the needle is furnished
with two metallic blades, the upper one of which is joined to the vertical axis and
is extended beyond the isolated portion of the needle in a shank terminated by a
a small roller wheel which passes over the extreme circumference of the dial, and
which in its revolution comes in contact with the metal pieces or reserves before
referred to. The lower metallic blade of the needle is in communication by means
of its elongated part with the lower metal portion of the vertical axis. This same
part of the axis is furnished with a spring acting as a needle, and which by bearing
against its surface (during the revolution of the axis in which it takes part) along
the circumference of the dial there meets the points of contact. This axis is
entirely of metal, as is the needle which it carries and which it carries round in its
revolution. This needle is also terminated by a metal roller wheel which meets the
points of contact on the dial. The sockets of the pivots of the vertical axis are
connected with the conducting coil. When at rest the needles in both dials are
parallel; the roller wheel rests on the isolated mass of the dial. In this position
of rest the needle is detained between the teeth of a double comb, the two portions
of which are composed of very flexible springs inserted in a non conducting
substance. The teeth of the upper comb are formed by the extremities of the
metallic wires which bear the points of contact of the dial. The teeth of the
lower comb are the ends of the wires which carry the points of contact of the
second dial. However the termination of the needles by the contact roller wheels
is not an indespensable condition to the satisfactory working of the instrument, as
a modification may be employed which oviates the necessity of the roller wheel,
the needle passing over the different points of contact between two springs. The
wire of the line leaving the central office is connected to a spindle, the lower rod of
which passes through an isolated support to form the pivot of the axis, and
consequently places part of this axis, the blade and the wheel, in communication
with the wire of the line by the blade and the teeth of the comb. When the
needle is at rest the system extends to all the points of the dial. The return wire
from the commutator to the central office is attached to a point of contact under
the roller wheel of the needle. Thus the axis, the coil conductor, the part of the
axis, the needle, the blade of the needle, and the lower comb with its ramifications,
are connected with this return wire. Either of the two electro magnets can at the

page_text: will of the central office be placed in the current of a local battery fixed at an
automatic post. To enable this to be done the working wire can receive at the
central office a series of emissions of a positive or negative current, the wire being
joined in the distance commutator to an electro magnet, above the arms of which
are fixed two permanent magnets, which are faced by two poles of the same, and
which move on their centres., Above these magnets are two spring blades attached
to a central axis which, when at rest, support the two magnets in a horizontal
position against the two regulating screws. Supposing a positive current sent
from the central office, this will attract the north pole of the magnet and will force
the spring to rise again and bear against a button. On the other hand the current
will have the effect of making the needle bear more against the second regulating
screw. Now the central point is connected to one of the electrodes of the local
battery, therefore this organ working as a relay and with inversion of current will
cause at each emission of a positive current in the working wire the passage of a
current from the local battery in the electro magnet, which by its frame and its
lever will cause the wheel of the disc to move one tooth forward, and the axis and
the needles to rotate proportionately. Before commencing the complete description
of the central office it is advisable to describe here the commutator utilized in the
sending and the inversion of the currents on the working wire. This apparatus
consists of a slide piece (said piece sliding on a shelf) which is composed of three
portions. The central part is isolated, the two outside portions are connected to
the two electrodes of a battery. The two extremities of these outside portions are
in contact with two fixed points, of which the first is in communication with the
soil, and the other carries a Morse key which, during its working, presses against
a point which joins a bifurcation of the working wire.
This bifurcation crosses
under a controlling dial, some parts of which apparatus at each emission of a
current cause a needle to move a certain distance in the same way as the needle of
the dial in the automatic post. If the moveable part of the commutator is slid
towards the left the current flowing in the distance commutator causes the needle
to work. The central office is informed of the position of this by the corresponding
position of the dial. Before examining the various cases which may practically
arise, and indicating the possible employment of different sets of the apparatus, I
will describe the installation of the apparatus at the subscribers end, and also of
that at the central office, merely stating that my system is applicable to all sorts
of transmitters or receivers, telephonic or telegraphic, with or without batteries,
and that the apparatus described is adapted for a method of utilising for a tele-
phonic service a system of batteries permitting the supression of batteries at the
subscribers end. The description will be based then on this special system, it
being understood that it may be modified for systems working without batteries
with the aid of magneto electric machines. The apparatus at the subscribers end.
is composed of a microphone, of a bell, and of a telephone, united in an apparatus
established on the wire of the line; the current which flows through this wire
works on the bell when the telephone is hung up, and on the telephone when the
same is taken down. Where it leaves the telephonic apparatus the wire of the
line meets the point of the centre of rotation of the key, which when in a state of
repose is in a vertical position, establishing the communication of the wire of the
line with the ground wire. If the wire of the line of the subscriber be followed
from its junction with the earth it will be noted that it passes through the key
and the telephonic apparatus, and thence by a wire towards a point on the
conductor which unites the metal reserves of the dials. Having reached these
points the wire is carried where is touches a key capable of conveying or with-
When
drawing the current of the apparatus similar to that at the subscribers end.
the telephonic apparatus is not under the influence of the current the latter then
passes from the key to a compass or galvano-meter. The preceeding is a description
of the mode of communication which is established across the commutator and the
wire of the line as far as the central office. At the spot where it leaves the
telephonic apparatus on the galvano meter the wire is joined to a fixed point of

page_text: the sliding commutator; this commutator is composed of a plate sliding on a shelf
formed of two metal portions separated by an isolated part, as before described.
This piece can be pushed to the right or to the left between four fixed points of
contact one point is joined to the conductor coming from one of the poles of a
battery, the second point to the wire of the line of the system, the third point to
the wire which establishes communication with these points dependant from three
other systems, and lastly at a fourth point to the ground wire. In the position of
rest the second point of the commutator is connected with the pole of the battery.
The conductor coming from the other pole of this battery joins the semi circular
commutator, the key of which performs several functions as before described, one
of which is its capability of being attached directly to the current which has been
followed from the earth at the subscribers end to the battery at the office. If the
pole of this battery is put in communication with the earth, a complete circuit will
be obtained, working the bell of the telephonic apparatus of the office and on thie
bell of the similar apparatus at the subscribers end. To obtain this result the key
of the commutator consists of two metallic portions separated by an isolated part,
serving at the same time as a "working button." If the key is put in contact
with the metallic circle fixed on the commutator and joined by a wire to the fixed
point of the sliding commutator, communication with the earth will have been
established.
When it is desired to call one subscriber only, it will be sufficient to
put the needle of the dial on the right side of the commutator at a distance on the
dial corresponding to this particular subscriber. This suppresses the part of the
current flowing through the comb, and establishes it directly between the point
where the wire of the line joins the automatic post and the special wire of the line
of the subscriber beyond that point. The circuit by the wire of the line starting
from the pole of the battery has already been explained. It first joins at a point
at the subscribers end and then joins the wire of line, which conducts the current
to the small right hand dial, as already described. The connexion, which is
established through the commutator between this point and the return wire passes
through the apparatus of the central office, where it joins by a bifurcation of the
semi circular commutator. When in a state of repose, the current coming from the
extremity of a semi circle fixed on the commutator has no means of egress, but
that on the contrary it joins the pole of the battery. The communication
established with a subscriber shuts off the current of the battery, and makes it
work on the bell of the apparatus of the central office and on the bell of the
subscriber. The central office is thus informed that a call has been made. To
ascertain the caller it is necessary to make the needle on the right dial revolve.
At the first movement the needle will leave the combs, and consequently the
current will be interrupted and the bells begin to ring, but they act differently
when the needle arrives in contact with the subscriber whose circuit is shut. A stop is
made in this position, and from this moment the communication of this one subscriber
will be established, so that no one can derange it or participate in it or ascertain the
number of the person with whom the subscriber wishes to be put in communication.
Suppose the subscriber 1 B wishes to communicate with the subscriber 3 C;
besides the central portion already described the commutator carries a semicircular
band offering points of contact corresponding to the other systems of various sub-
scribers. The official in charge of the system C being informed of the request for
communication with one of his subscribers, he immediately puts the bell out of the
circuit by working a Morse key, and after being informed of the reason for the
enquiry he calls the subscriber 3C by the means already described. This
subscriber 3 C being therefore informed of the enquiry, and all the other subscribers
of the group being isolated, the official slides the commutator towards the left and
lowers the key, so that the current coming from the system B passes by the
commutator to the point where it meets the key which when lowered puts the
telephone of the office out of the current, making the same pass by the wire which
surrounds the galvano meter. The official in charge of the system B has made the
same arrangement of parts, and from this moment 1 B and 3 C are in communication

page_text: without anyone, be he subscriber or official, being able to hear their conversation.
The conversation finished, 1 B places his key back in the vertical position which
breaks the circuit. This interruption is signalled to the two officials in charge of the
systems B and C by the return of the needle of the galvano meters to zero. If during
'this exchange of conversation another subscriber on the systems B or C desires to
speak, he places his key in the horizontal position or position of call, when his bell
will ring. This effect can be produced in two ways. The conversation between 1 B
and 3 C being finished, the officials put back all the instruments to the position of
repose. Now the needles of the distance commutators should finish their revolutions
on the dial and return to the point of rest. If, for instance, in the system B the
the subscriber 3 B put himself, as has just been said, in the position of call, the bell
of this subscriber and that of the central office will ring as soon as the needle
arrives on the point of contact corresponding to this subscriber on the dial, and the
subscriber will be informed that his turn has arrived. The official at the office
will immediately know the number of the caller, for the needle of the controlling
dial will inform him of this. There is yet another bypothesis, namely, that of a
subscriber wishing communication with a colleague on the same system, as, for
example, 2 D with 4 D. It is needless to further explain the request of the first.
and the call of the second, which is made as in the preceeding cases, but the working
of the dial at the left of. the distance commutator may be explained. The current
follows exactly the same route by the wire of the line and the return wire of the
subscriber 2 D as far as the centre of the left dial, but the needle of the left dial
has been put by the means before indicated in contact with the point on the left
dial corresponding to the subscriber called, and consequently instead of returning
to the central office the current is sent from this central point across the contact
and the wire by which it is attached to the wire of the line of the subscriber 4 D,
The official at the
through whose apparatus it passes eventually to the earth.
central office is informed of the closing of the conversation by the needle of his
galvanometer. I finish the description of my system of telephonic apparatus by
describing a means by which one telephonic apparatus may be made to take the
It is well known how
place of several different instruments in one house.
disagreable and fatiguing it is when using the telephones now in vogue to have to
go at each call towards the one apparatus fixed in the house, or otherwise to have
an apparatus in each room. To obviate this inconvenient arrangement, in each
place where it is intended to employ the telephone is fixed a tablet furnished
laterally with two spindles acting as pivots for two little tubes forming hinges and
mounted on a single box containing the mechanism of the transmitter and receiver,
which can thus (by this capability of displacement) be utilized for many sets of
apparatus. At the opposite side to the hinges the box carries a hook let down by
the action of a spring and hooking into a fixed sheath so as to insure the perfect
contact of the box with the tablet. On the interior surface of the box, bearing
against the tablet, are projections in form similar to wedges, in number equal to
that of the wires with which the telephone communicates. Each wedge is composed
of two metal portions, separated by an insulation plate. The tablet has openings
corresponding to the size, number, and position of the wedges, at the bottom of
which are two curved springs. When the box is not closed on the tablet these two
springs touch, and the ground wire, the wire of the line, and the battery wire pass
through the instrument. If however the telephonic apparatus is put in position
the wedges pass between the springs, breaking the direct communication and causing
a deviation of the circuit which is used in the ordinary way.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Philip Middleton Justice in the Great Seal Patent Office on the
11th August 1881.
PHILIP MIDDLETON JUSTICE, of 14, Southampton Buildings, in the County
of Middlesex, Patent Agent. "IMPROVEMENTS IN APPARATUS EMPLOYED FOR
AND IN TELEGRAPHIC OR TELEPHONIC COMMUNICATION." A communication from
abroad by Jacques Victor Michel Bartelous, of Brussels, in the Kingdom of
Belgium.
"
The first series of apparatus permits the establishment on a system of three wires
of an unlimited number of subscription stations or telegraphic offices, giving to each
the right of calling a central office. By the help of this office the different stations
can be put in communication with each other, or with other lines; for the time being
all communication on the system is stopped except between the "caller" and the
called." If it is wished to limit the enquiries and communications on the system,
the number of the wires can be reduced to two; but the system of three wires has
this advantage that during the communication of a "caller" a wire remains free,
either to put this subscriber in communication with another subscriber on the same
system, or to call all the subscribers, or the offices, including that already at work,
to put them in communication with another enquirer. The second series of
apparatus refers to the installation at any required distance from a central office
of an instrument, which may be called a distance commutator, and which does
away with the necessity of the establishment of an auxiliary office, substituting
therefore an automatic station. Around this apparatus and connected to the
central office by a system of two or three wires any number of telephonic subscribers
or telegraphic offices can be connected. The Drawings annexed to and forming
part of the present Specification are prepared on the hypothesis of the existance of
a system of three wires. In this case the system described permits,-
1. Each subscriber or each office to call the central office, and to be put by that
into communication with any telephonic or telegraphic apparatus on the systein.
2. The central office to call any subscriber or any office of a group at will
without producing a call on another, and to communicate anything it may desire.
3. It permits two subscribers in the same group at a distance from each other to
be put into communication by the electrical working of the apparatus of the
automatic post.
When the service described in paragraph 3 is not in use, or when it is wished to
reduce the system to two wires, and the construction of the distance commutator to
one dial plate only, this apparatus would then undergo important simplification.
Reserving to myself the subject of the complete or modified application of the
system, I shall have occasion in developing this Specification to refer to some
modifications resulting from the reduction from the one or the other system to two
wires, and explain various apparatus, such as commutators, galvano-meters, &c., in
use at the central office or at the subscribers, to facilitate the working of the
currents, or to ensure the privacy of the communications. I conclude these general
remarks by saying that the following description treats of the supposed installation
of a system of three wires applied to a telephonic working, at the same time
expressly claiming the use of similar apparatus for telegraphic working:

page_text: The subscriber at No. 1 D has requested communication with No. 4 D. This
result is obtained by the means employed in the systems B and C; but the
junction of the wires of the line and of the return is made on the one commutator
of the system D.
The plant at the central office includes for each system a circular commutator M,
M³, M³, M³, divided into two parts, each furnished with a working needle. The
wire of the line is joined at the central point of the rotation of the upper needle
and the extremity of the return wire to the central point of rotation of the lower
needle; each of these wires passes (before arriving at the commutator) through a
telephone with a bell which can be admitted in the current, or a galvanometer on
current at will. On leaving the commutator the wire of the line when at rest is
connected with the soil at S, whilst the return wire is isolated and eventually is
placed in communication with a battery or an electro magnetic machine at P. The
working wire is also in communication with a battery N by the aid of a Morse
key, and before leaving the office the currents which are sent pass through the
mechanism of a dial apparatus on which they move a needle. The system A being
shown at rest it is seen that every current from a battery or from an electro
magnetic machine sent from any subscriber's station will act on the bell of
the wire of the line in the office. But in order for a subscriber to be enabled to
despatch this current he must first perform certain movements with his apparatus
which will be hereinafter set forth. In addition to the apparatus actually in
use, the plant at each subscribers must include the apparatus as shown in the
different Drawings on Sheet II. This apparatus includes an electro magnet A, A,

page_text: (Fig. 1 & 2), governed by the working wire of the system. The current sent at
will from the central office passes through this wire, acts on the electro magnets by
causing a lever to oscillate which governs a double toothed cog wheel B, B', so
arranged that each movement of the lever causes the wheel to advance one tooth
only. This movement of the wheel causes the rotation of the disc D, D (Figs. 1,
2, 3, and 4), presenting the semi circular notch a, a¹ (Figs. 1 and 3) to its circum-
ference, across which when the disc is in a position of repose, the plate b³ terminating
the shank b¹ of the button 6 (Fig. 4) passes freely. As soon as the disc is in its
place the passage of the current is no longer possible. The pressure of the button b
causes the call bell to be rung by means of the wire of the line; this is effected by
the current of the battery or of the electro magnetic machine arriving by the
conductor c, d, e, f, fixed on the front of the box passing through the arm of the
rod G, F, the conductor C, h, the bell S (and later the telephone T when that is
unhooked), and finally the conductor i, j, the extremity of which is in cominunica-
tion with a metal cylinder "o," in which works the shank b¹ of the button b.
When the button is at rest the current is stopped at this point, but as soon as the
button is pushed in the plate b. comes in contact with the spring r, terminating
the wire of the line which is joined in the apparatus to the conductor K, K', KII.,
the spring which when at rest is in contact with the metal cap m surrounding
the disc Ď, whilst it breaks this contact when the button is pushed in which causes
it to take the position. Suppose a call to be sent to the central office :-As soon
as it is produced four successive emissions of the current are sent through the
working wire; this has the effect as shown in the Drawings of causing the toothed
wheel to advance four divisions, that is to say, one twelfth part of the circum-
ference. This effect is produced in all the apparatus causing the discs to advance
one twelfth part of their circumference and will prevent any other subscriber from
pressing his button to effect communication, besides he will be informed of this
fact by a special arrangement formed as follows:-The discs are painted in two
distinctive colors, such as red and blue; the greater part of the surface is red except
a sector of a twelfth part of the circumference, of which the lower radius is
horizontal and which is painted blue; in Sheet 2 it is shown as being cross
sectioned. The portion of the front face of the box corresponding to this sector is
colored in the same shade and cross sectioned. It has the words fermè (or closed)
on it cut out on a thin plate; so long as this blue sector is at the back of these cut
out letters the word will hardly be apparent, but when the disc turns and the red
color shows through the cut out letters the words will show out very plainly and
the subscribers are thus inforined that the system is in use. They have however a
means of applying for communication in their turn; this is afforded them by the
working of the rod G, F, which they can raise to the position G, F1, the action
of the rod in the position G, F, conducting the current from f in G, h, has been
before explained. On the other hand, in the position G, F, the rod will be
found in contact with the metallic button on the front of the box, and crossing
its front face to become on the opposite side the point of attachment of the
spring g, l, bearing on the disc D. The discs are constructed of non conducting
material with the exception of the metal cap m, m, m, and of the metallic
needlen, n¹, placed on the interior face. Supposing that on the circumference
of the discs there were a number of stopping points equal to half the number
of teeth in the notched wheels, it will be seen that the Figures on Sheet II.
would represent 24. Of these twenty four positions two are taken by the sector,
the 22 remaining ones correspond by hypothesis to a number equal to the
subscribers. Now the needles n, n' are arranged so that each shall occupy a
different position of projection in the case where all the discs would be in contact,
and where each of these positions correspond to one of the divisions of the circum-
ference and to a number in rotation which corresponds to the subscribers number.
On the point of the circumference of the cap which corresponds to the extremity of
the needle, the cap bears on the front of the disc an internal projection O, the
object of which will be explained. If one or more subscribers are placed in waiting

page_text: position during an exchange of conversation, the following fact occurs:-The
conversation ended, a successive emission of currents sent by the central office
through the working wire, sets all the discs in rotation so as to bring them back to
the point of rest. During this movement the projections O of the caps, successively
and in numerical order, pass under the extremity 7 of the spring. If the rod G, F
is lowered, that is to say, if the button g is detached, this passage will produce no
effect; but if on the contrary the rod be lifted, the current of the battery arriving
by c, d, e, will be connected with the button g, and the spring g, l, by means of the
lever F, G. At the moment of its passage by the projection O (Fig. 3) the current
passes to the metal cap. Now I have already said that when the button b, b' is
not pushed in, the spring r terminating the conductor of the wire of the line is in
contact with the metal cap. From that time, during the rotation of the discs, each
time a projection 0 meets a spring g, l, in communication with the subscriber's
battery will cause a current which will be regulated and registered with the
subscriber's number at the central office. It must be observed that the current
working the bell of the central office will not act on that of the subscriber, because
às regards the latter it no longer traverses G, h, 8, i, j, the closing in j only taking
place by pressing in the button. At the first waiting call met with in this
operation, the central office will reply by sending a current from its battery
through the return wire. This latter is connected with the piece P fitted with a
spring R, pushing against the interior face of the disc. Whilst the projection O
meets the extremity 1 of the spring g, l, the needle n, n¹ meets the extremity q of
the spring R. This needle is in communication through the axis Z of the disc
with the conductor s, t, directing the current into the ground by t¹ through the
bell S, Fig. 1 and 2. The subscriber thus informed will wait the return of the disc
to the resting point, the return to which will be signalled by the disappearance of
the word "fermè" in red letters. Then he can push in the button to send his
communication. The other waiting calls noted by the continued movement of the
discs will be simply registered to take their successive turns without the subscribers
being disturbed before their turn comes. The explanations I have given as to the
manner of informing the subscriber who has been called first will dispense with the
necessity of explaining the way by which a subscriber can be called by the central
office. The working of the apparatus at the central office is shown in Fig. 6, on
Sheet 1, shewing, first, the system A at rest; 2nd, the system B receiving the
call of a subscriber; 3rd; the system C being used to call a subscriber; and 4th, the
system D giving the communication to two subscribers of this series deserving to
communicate with one another. The dials K, K', K2, K3 of the apparatus serve to
regulate the movement of the discs and to establish the numerical order of the
subscriber communicated with; their needles are worked by the batteries N, N',
N2, N3, crossing the working wires and regulated by the Morse keys m, m³, m², m³.
The commutators M, M³, M2, M3, the conception and disposition of which I claim,
series'
can, by a simple rotary movement of the needle, put the wires of a line of
in communication either with the return wire of another, or with the return wire
of the same system, or even permit the making or the cutting off of the commu-
nication of these same wires with the battery or with the earth. The inspection of
Figure 4 (Sheet 2) will show that it is sufficient for the subscriber who has held
his communication to slightly withdraw the button from the entire stroke, in order
to relieve the plate B" from contact with the spring r, and without hindering the
rotation of the disc. This gentle removal of the button is used to give notice to
the central office of the close of the conversation. It is thus seen that the currents
of communication pass to the central office by the galvanometers which signal the
existance, or the suppression of the current. This permits of the end of a
conversation being signified without connection with the office.

page_text: 3. The return wire by & line dotted —. ·
It is to be noted that the distance commutators or automatic posts are represented
as disconnecting each of the four auxiliary posts, and that the Drawings show the
plant of the central office corresponding to the junction of four systems, but the
number of points of contact to be placed on the commutators to be served by
the central office are undetermined.
Description of Distance Commutators, Sheet III., Figs. 7 and 8.-As indicated by
its name, this instrument permits the changing at any distance the direction of an
electric current, so as to bring it by a single wire to a given point, and to diverge
It
it from this point to an unlimited number of auxiliary stations, and vice versa.
consists essentially of two horizontal dials A, A, A", A", of similar size placed side
by side, and of a third dial A', A', which is smaller and placed parallel, but below
the dial A, A. The dials are constructed of some non conducting material, and in
their circumference have some metal pieces or reserves marked 1, 2, 3, 4, on the
dial A, A; 1, 2, 3, 41, on the dial A", A", and 11, 21, 31, 4', on the dial A¹, A¹.
The points of contact 1, 2, 3, 4, are attached to the points 1, 2, 31, 41, by metal
wires I., II., III., IV., which join in 1, II., III., IV., the wires of the line which are
directed from the commutator towards the instruments of each subscriber of the
group. From each of these subscribers instruments a wire proceeds which meets
in proper order the points 11, 21, 31, 41, of the dial A', A. The centres of the
dials A, A, A', A', are pierced by two vertical axis C¹, C, which receive their.
rotary movement by means of the two cog wheels attached to the axles, and
marked D, D', (to render the drawing intellegable, the wheel D has not been shown
in Figure 7). These wheels are worked by the levers 1, 1, attached to the stays of
two electro magnets E, E, E, E'. The axis C, C¹, is composed of two metallic
pieces C and C¹, separated by an isolating piece F, on which is supported the also
isolated central portion of the needle B. The needle is furnished with two metallic
blades, the upper one of which b; b, is joined to C of the vertical axis, and is
extended beyond the isolated portion of the needle in a shank, terminated by a
small roller wheel G which passes over the extreme circumference of the dial A, A,
and which in its revolution cones in contact with the metal pieces or reserves
1, 2, 3, 4. The lower metallic blade c, c, of the needle B, is in communication by.
means of its elongated part with the lower metal portion C' of the vertical axis.
This same part C is furnished with a spring B' acting as a needle, and which by
bearing against its surface (during the revolution of the axis in which it takes part)
along the circumference of the dial A¹, A', there meets the points of contact
1, 2, 3, 4. The axis C" is entirely of metal, as is the needle B which it carries
round in its revolution; this needle B" is also terminated by a metal roller.
wheel G, which meets the points of contact 11, 2, 3, 41 The sockets h, h¹, of
the pivots of the vertical axis are connected with the conducting coil H, H.
When at rest the needles B, B", are parallel, as shown in Figure 7 (Sheet III.).
The roller wheel G rests on the isolated mass of the dial A, A, and the wheel G' on
an additional contact with the dial A", A", at J. In this position of rest the
needle B is detained between the teeth of a double comb K, K¹, the two portions
of which are composed of very flexible springs inserted in a non conducting
substance. The teeth of the upper comb K are formed by the extremities of the
metallic wires which bear the points 1, 2, 3, 4, of the dial A. The teeth of the lower
comb K' are the ends of the wires which carry the points of contact 11, 2¹, 31, 4',
of the dial A", A". However, the termination of the needles by the contact roller
wheels is not an indespensible condition to the satisfactory working of the instru-
ment. Figure 9 shows the arrangement which obviates the necessity of the roller
wheel by the needle passing over the different points of contact between two
springs. In this case the metal part or pieces 1, 2, 3, 4, are above the plane of the

page_text: needle's rotation, and are connected by the spring "a
" with "b, b," and the upper
extremity C of the axis C¹. The dial A¹, A', occupies the position originally
taken by the dial A, A, and the points 11, 21, 31, 4' have their communication with
the part of the axis by means of the spring a' and of the blade 6", 6", combining
in them the functions of the blade c, c, of the needle B in Figure 8. The wire of
the line leaving the central office is connected to the spindle Q (Figure 8) the lower
end of which passes through an isolated support to form the pivot of the axis C, C¹,
and consequently places the part C of this axis, the blade b, b, and the wheel Ġ in
communication with the wire of the line by the blade b, b, and the teeth of the
comb. When the needle is at rest the system extends to all the points 1, 2, 3, 4,
of the dial A, A. The return wire from the commutator to the central office is
attached to the contact J under the roller wheel C³ of the needle B¹¹ Thus the axis
CH, CH, the coil conductor H, H', the part C¹ of the axis C, C¹, the needle B¹, the
blade C, C, of the needle B, and the lower comb with its ramifications to the
points 11, 21, 31, 41, are connected with this return wire. Either of the two electro
magnets E, E, E¹, E¹, can at the will of the central office be placed in the circuit of
a local battery N fixed at an automatic post. To enable this to be done the working
wire can receive at the central office a series of emissions of a positive or negative
current; the wire d is joined in the distance commutator to an electro magnet H, H¹,
above the arms of which are fixed two permanent magnets N, S, N', S', which are
faced by two poles of the same, and which move on their centres. Above these
magnets are two spring blades 7, 14, attached to a central axis, which when at rest
support the two magnets in a horizontal position against the two regulating
screws ff. Supposing a positive current sent from the central office to H, this
will attract the north pole of the magnet N, S, and will force the spring to
rise and bear against the button L. On the other hand in H¹ the current will
have the effect of making the needle N¹, S', bear more against the regulating
screw f. Now the central point M is connected to one of the electrodes of the
local battery N, therefore this organ working as a relay and with inversion of
current will cause at each emission of a positive current in the working wire the
passage of a current from the battery Ñ in E, E, which by its frame and its
lever will cause the wheel D to move one tooth forward, and the axis C¹ and
the needle B to rotate proportionately. The same effect will be produced in E¹, E¹,
from each emission of a negative current, and by the lever the wheel D', D¹,
will turn the axis 0" of the needle B¹¹ A modification of the foregoing arrange-
ment is shown in elevation in Figure 20, Sheet 4, while the Figures 21, 22, 23,
represent sectional elevations on the lines ab, ed, ef, of Figure 20. The
Figures 24, 25, 26, 27, represent the apparatus in different positions at the sub-
scriber's end. The horizontal dial plates A, A, A", A", (Figs. 7 and 8) are joined in
one, which is in a vertical position, and which is shown at AN, AN, (Figs. 20 and
21), the contacts 1, 111, 2, 21, 3, 3, 4, 4", of the dials A, A", which are coupled
by wires of communication, are replaced by the single contacts 1", 2", 3", 4". The
dial A¹ also becomes vertical at AM, AN, (Figs. 20 and 23), and the contacts
1, 2, 3, 4, are disposed on it at 1, 2, 3, 4. The needles B, B", become
simple springs gliding gently, over the contacts. The needles become respectively
B=B³, B¹=Bª, B=B°. In order to render the Drawings clearer the two needles
B and B are not shown in their position of rest, but are represented in com-
munication with the contacts of one of the subscribers. When at rest the needle Ba
(Fig. 21) projects under the needle B°, and with the needle B (Fig. 23) has a
vertical position. The contact J (Fig. 7) corresponds to the contact J (Fig. 21),
but the wire Y', Y', which connects it to the central office (see Fig. 17, Sheet 5)
is suppressed, and this contact is therefore in communication with the earth at the
automatic post at the auxiliary office. The two needles Bº, B, are fixed to the
same axis C, Cl, and participate in its rotary movement. The needle B is mounted
on a washer which electrically isolates it from the axis and the needle B. The
needle B° is mounted on the axis C completely independant of the axis C, C²,
but connected by electrical communication to the needle B. The double comb

page_text: K, K', (Figures 7 and 8), by means of which and the medium of the needles B, B¹,
the two portions of the axis C, C', are put in communication with the contacts
1, 2, 3, 4, 1, 2, 3, 4, and the wires of the corresponding subscribers is replaced
by a single comb K" (Figs. 20 and 22) placed under the axis C, C, and each of the
teeth 1d, 2d, 3d, 4d, of this comb is connected to a corresponding contact of the
dial A. A rod t, t, excentric to the axis C, C', is mounted on this, and participates
in its rotary movement, so that when the needles Bª, B, are turned vertically
towards the base the rod t, t, rests on all the teeth of the comb K. The rotary
novement of the axis C, C, and C, is produced, as before mentioned, by the
action of the electro magnets E, E, E', E', on their armatures furnished with levers
which work on the cog wheels D, D¹, (Fig. 20); but by the arrangements herein-
after set forth the length of the needles B, B, Bo, is rendered independant of the
number of teeth in the comb, and consequently of its length. The result of this
modification is that the cog wheels D, D', only require to have a number of teeth
equal to the number of contacts to be established. Consequently the needles can,
by a single emission of current which works. them, pass from one contact to the
other contact without any intermediary movement. The Drawing only shows four
contacts, but in practice the apparatus will have 20 or more. As to the inversion
of the current caused by the electro magnets H, H¹, it is so far modified that the
magnets SN, S¹N', become vertical and parallel, the action remaining precisely
the same, as previously described. The suppression of the return wire Y₁, Y, Y₁,
does not prevent the apparatus from rendering the functions previously described.
In reality the position of repose of the apparatus at the subscriber's is caused by
the junction (by means of the handle of the commutator) of the wire of the
line with the wire of return (Figs. 24, 25, and 27), and the calling position by
putting the wire of the line in communication with the earth (Fig. 26). The
following circunstances may occur in the three cases which may arise :-
1st. A subscriber calls the central office by connecting the wire of the line with
the earth (Fig. 26), this which joins the automatic post at the central office leaves
the axis C, and goes into the earth through a battery or an electro magnetic
apparatus in the office. The current then passes from the subscriber's, across the
bell, follows its wire of the line, and comes out at the corresponding contact of the
dial AN (Figure 21) and the tooth of the comb Ka, which corresponds with it,
thence by the rod t, t¹, (indicated in dotted lines) to the axis C and to the wire
of the line of the central office.
2nd. The central office wishes to call a subscriber. The official works the
automatic apparatus so as to work on the axis C, C, and bring the needles
B and B under the corresponding contacts of the wire of the line, and the return
wire of such subscriber. The current leaves the central office and passes through
the battery or magneto electric apparatus; it follows the wire of the line up to the
axis C, C, and passes through the needle B into the wire of the line of the
subscriber, passes through his bell, and comes back by the return wire to its
contact on the dial A, then follows the electric communication established between
this and the axis C, and through the needle B° at rest on the dial J looses itself
in the earth at the auxiliary office.
3rd. A subscriber wishes to be put in communication with another connected
like himself to an automatic post. The central office receives the call, and working
on the axis C, C₁, puts the needles B and B over the contacts of the subscriber
called for and informs him that he is called. Then by means of working the
axis C the needle B° is placed over the number of the subscriber who has asked
for communication. From that time the current goes out by the wire of the line
and by the needle B° to the axis C passes through the electric communication
astablished at the needle Bm placed on the return wire of the second subscriber,
and returns by his wire of the line to the needle Bu, and from there by the axis C¹¹¹
to the central office where the final communication with the earth is established.
Before commencing the complete description of the central office it is advisable
to describe here the commutator utilized in the sending and the inversion of the

page_text: currents on the working wire. This apparatus consists of a slide piece, said piece
sliding on a shelf is composed of three portions g, f, and g¹; the central part fis
isolated (Sheet 5, Fig. 12), the two portions g and g¹ are connected to the two
electrodes of a battery P. In the position occupied by the commutator in Fig. 12,
as well as in the Figures 13 and 14, the two extremities g, g', are in contact with
two fixed points of which the first O is in communication with the soil, and the
other R carries a "Morse key" "m,” which during its working presses against the
point e, and this point e joins a bifurcation d, e, of the working wire. This bifur-
cation crosses under a controlling dial V, some parts of which apparatus at each
emission of a current cause a needle to move a certain distance in the same way
as the needle B of the dial A in the automatic post. If it is wished to cause the
moveable part of the commutator to slide towards the left, as shown in Figure 15,
g', here termed g, leaves the point R and moves against O' in communication
with the ground. The part g leaves O' and returns against a piece R¹¹ placed
towards the left in a similar position to R". This piece R carries as well a
Morse key acting in the same way as the key m (Figure 12), but sends
through a bifurcation e" and under a dial V' a current inverse to that which
travels as far as e, d, under the dial V. The result is that the current now flowing
in the distance commutator causes the needle B" to work. The central office is
informed of the position of this by the corresponding position of the dial Vi
Before examining the various cases which may practically arise, and indicating
the possible employment of different sets of the apparatus, I will describe the
installation of the apparatus at the subscriber's end, and also at that of the central
office, merely stating that my system is applicable to all sorts of transmitters or
receivers, telephonic or telegraphic, with or without batteries, and that the
apparatus shown on Sheet 5 represents the method of utilising for a telephonic
service a system of batteries, permitting the suppression of batteries at the sub-
scribers end. The description will be based then on this special system, it being
understood that it may be modified for systems working without batteries with
the aid of magneto electric machines..
The apparatus at the subscribers end represented at 14 (Figure 16) is composed
of a microphone, of a bell, and of a telephone, united in an apparatus established
on the wire of the line, the current which flows through this wire works on the
bell when the telephone is hung up and on the telephone when the same is taken
down. Where it leaves the telephonic apparatus the wire of the line meets the
point &, the centre of rotation of the key a, b, when in a state of repose is in a
vertical position establishing the communication of the wire of the line with the
ground wire at the point b. If the wire of the line of the subscriber 1ª be
followed from its junction with the earth at S, it will be observed that it passes
through the key b, a, and the telephonic apparatus and thence by x, x, x, x,
towards the point I on the conductor, which unites the metal reserves J, 1¹, of the
dials. Having reached this point the wire is carried to x (Figure 12), where it
touces a key capable of conveying or withdrawing the current from the apparatus T
similar to that at the subscriber's end. When the telephonic apparatus T is not
under the influence of the current, the latter then passes from the key to a compass
or galvano meter M. The preceeding is a description of the mode of com-
munication which is established across the commutator between the point I
and the wire of the line as far as the central office. At the spot where it leaves
the telephonic apparatus or the galvanometer at Z or Z' the wire is joined to the
fixed point of a sliding commutator; this commutator is composed of a plate
sliding on a shelf formed of two metal portions G, H, separated by an isolated
part. This piece can be pushed to the right or to the left between four fixed points
of contact i, h, j, k. At the point it joins the conductor coming from one of the
poles q of the battery N; at the point the wire of the line of the system, at
the point to the wire r, pl, ru, zu³, 20%, which establishes communication with
the points A, A, A, dependant from three other systems, and, lastly, at the point k
to the ground wire S, S'. In the position of rest indicated in the Figure 12 the

page_text: point h of the commutator is connected with the point i, which is the pole g of the
battery N. The conductor coming from the other pole of this battery joins at m,
the semicircular commutator z, the key of which performs several functions, as
before described, one of which is its capability of being attached directly to the
circuit which has been followed from the earth at the subscriber's end to the battery
at the office. If the pole of the battery N is put incommunication, via "m," with
the earth a complete circuit will be obtained working the bell of the apparatus T of
the office, and on the bell of the similar apparatus at the subscribers end 1 A. To
obtain this result the key m, o, n, of the commutator Z consists of two metallic
portions separated by an isolated part O, serving at the same time as a "working
button." If by means of the parts o, m, the key is put in contact with the metallic
circle p, p, fixed on the commutator and joined by a wire p, k, to the fixed point k
of the sliding commutator, communication with the earth will have been established
by S, S¹. When it is desired to call one subscriber only it will be sufficient to put
the needle of the dial on the right side of the commutator at a distance on the dial
corresponding to this particular subscriber. This suppresses the part of the current
flowing through the comb and establishes it directly between the point where the
wire of the line joins the automatic post, and the special wire of the line of the
'subscriber beyond that point. With reference to the return wire it will be observed
in the apparatus 1ª that it starts from a point c, and that it is only necessary to
raise the key a, b, in a horizontal position a, c, to cut off the communication with
the earth and establish it with the wire of the line and the return wire; this simple
motion signals to the central office the request for communication made by the
subscriber, and the current flows in the way shown by Figs. 13 and 17 (system B),
in which system it is assumed that the subscriber 1 B is calling. The circuit by
the wire of the line starting from the pole q¹ of the battery N₁ has already been
explained. It first joins at the point a at the subscribers end 1 B, and then by a, c,
joins the wire of the line which conducts the current by Y, Y, Y, to the point 1¹ on
the small right hand dial. As already shown, the connection which is established
through the commutator between this point and the return wire passes by Y', Y', Y¹,
and the apparatus B of the central office, where it joins by a bifurcation the two
points t' and ' of the semicircular commutator Z'. It is clearly seen from Figure 12
that in a state of repose the current coming from the point u the extremity of a
semi circle u, v, vl, fixed on the commutator has no means of egress, but that on the
contrary it passes from t to m to join the pole of the battery N.
communication established with the subscriber 1B (Figure 17) between the
points a and c shuts off the current of the battery N' and makes it work on the bell
of the apparatus T¹ of the central office and on the bell of the subscriber. The
central office is thus informed that a call has been made from group B. To
ascertain the caller it is necessary to make the needle on the right dial revolve.
At the first movement the needle will leave the combs, and consequently the
current will be interrupted and the bells begin to ring, but they act differently
when the needle arrives in contact with the subscriber whose circuit is shut.
stop is made in this position, and from this moment the communication of this one
subscriber will be established, so that no one can derange it, or participate in it,
or ascertain the number of the person with whom the subscriber wishes to be put
in communication. Suppose that 1B wishes to communicate with 3 C. Besides
the central portion already described, the commutator Z' carries beyond the
semicircle u, v, 111, a semicircular band offering points of contact at letters
corresponding to the other systems of the various subscribers, for example, the
points A, C, D. The part o¹, n¹, of the key being placed on the point c, the current
undergoes two modifications; 1st, that which I have before indicated frees the
pole from its communication with the return wire to put it in communication
with the earth by S", K', p', p², m¹², P; and, secondly, on the return wire at its'
bifurcated end, in place of going forwards by t¹ which becomes an isolated point'
at u and at the extremity of the key, it runs off in a wire connected with the
contact C, and by which it is conducted through the apparatus of the central
The
A

page_text: office, corresponding to the system designated by this letter, where it is joined to
the point J of the sliding commutator G¹¹, H. To put 1B in positive
communication with 3C this commutator ought to be represented in its position to
the left. Referring momentarily to Figure 12, it is seen that the wire r, 1, common
to all the systems terminates at the point J (corresponding to J, Figure 14),
and is thus in electrical connection with the earth through the part H of the
commutator. The same result is produced by sending the current from system B
through the apparatus of Figure 14, said current working on a bell F intercolated
in its circuit. The official in charge of the system C is thus informed of the
request for communication with one of his subscribers; he immediately puts the
bell F out of the circuit by working a Morse key, and after being informed of the
reason for the enquiry he calls the subscriber 3 C by the means already described.
This subscriber, 3 C, being therefore informed of the enquiry, and all the other
subscribers of the group being isolated, the official slides the commutator G¹¹, H¹,
towards the left and lowers the key J', so that the current coming from the
system B and joining at j passes by the part G₁ of the commutator to the
point, where it meets the key J, which when lowered puts the telephone
of the office out of the current, making the said current pass by the wire
which surrounds the galvano meter M¹. The official in charge of the system B
has made the same action in lowering the key J. From this moment 1B
and 3C are in communication without any one, be he subscriber or official,
being able to hear the conversation. The conversation finished, 1 B places his
key back to the vertical position which breaks the circuit. This interruption
is signalled to the two officials in charge of the systems B and C by the return of
the needle of the galvano meters M and M¹ to zero. If during this exchange
of conversation another subscriber on the systems B or C desires to speak, he
places his key in the horizontal position, or position of call, when his bell will
ring. This effect can be produced in two ways. The conversation between 1 B
and 3 C being finished, the officials put back all the instruments to the position of
repose. Now the needles of the distance commutators should finish their revolu-
tions on the dial and return to the point of rest. If, for instance, in the system B
the subscriber 3B put himself, as has just been said, in the position of call, the bell
of this subscriber, and that of the central office, will ring as soon as the needle
arrives on the contact 3 of the dial, and the subscriber will be informed that his
turn has arrived. The official at the office will immediately know the number of
the caller, for the needle of the controlling dial will inform him of this. If, for
example, in the system C, the subscriber 10 has called, the needle starting from
the point 3 will not meet the contact before arriving at its point of rest, but will
signal the closing of the system in returning to the comb, the working however
will be continued till it reaches the point 1. There is yet another hypothesis,
namely, that of a subscriber wishing communication with a colleague on the same
system, as, for example 2 D with 4 D. It is needless to further explain the request
of the first, and the call of the second, which is made as in the preceeding cases, but
the working of the dial at the left of the distance commutator (Fig. 15 and 19)
may be explained. The current, as shown by the line to the earth at S11, follows
exactly the same route by the wire of the line and the return wire of the
subscriber 2 D as far as the centre E of the left dial, but the needle of this dial
has been put, by the means before indicated, in contact with the point 411 of the
left dial, and consequently instead of returning to the central office the current is
sent from the central point E across the contact 4, and the wire by which it is
attached to the point IV. in the wire of the line of the subscriber 4 D, through which
it passes eventually to the earth. The official at the central office is informed of
the closing of the conversation by the needle of his galvanometer. I finish the
description of my system of telephonic apparatus by describing a means by which
one telephonic apparatus may be made to take the place of several different instru-
ments in one house. It is well known how disagreable and fatiguing it is when
using the telephones now in vogue, to have to go at each call towards one apparatus

page_text: fixed in the house, or otherwise, or otherwise to have an apparatus in each room. To
obviate this inconvenient arrangement, in each place where it is intended to employ
the telephone, is fixed a table A, B, (Figs. 10 and 11) furnished laterally with two
spindles a and b acting as pivots for two little tubes c, d, thus forming hinges, and
mounted on a single box C, D, E, F, containing the mechanism of the transmitter
and receiver, which can thus (by this capability of displacement) be utilised for
many sets of apparatus. At the opposite side to the hinges the box carries the
hook G let down by the action of the spring r, and hooking into a fixed sheath H
so as to ensure the perfect contact of the box with the tablet A, B. On the interior
surface of the box bearing against the tablet are projections in form similar to
wedges, in number equal to that of the wires with which the telephone commu-
nicates; Fig. 11 shows three of them, on the assumption that there is a wire of the
line, a ground wire, and a battery wire. Each wedge is composed of two metal
portions ff', separated by an insulation plate g (Fig. 10). The tablet has openings
corresponding to the size, number, and position of the wedges, at the bottom of
which are two curved springs h, h'; when the box is not closed on the tablet these
two springs touch, and the ground wire, the wire of the line, and the battery wire
pass through the instrument. If however the telephonic apparatus is put in
position, the wedges pass between the springs breaking the direct communication,
and causing a deviation of the circuit which is used in the ordinary way; Figure 10
represents the box in the two positions, the upper portion with wedge e not pushed
in, the lower portion with wedge e¹ introduced between the springs. After having
thus fully described, my Invention, and the method of utilizing the same,
What I claim and desire to secure by Letters Patent is,-
1st. The apparatus, means, and combinations to obtain either by the rotation of
a disc (1st series), or by the revolution of a needle (2nd series), communications,
increased or multiplied at will, between certain telegraphic or telephonic points,
substantially as described in this Specification, and as shown in the annexed
Drawings.
2nd. The sliding or other commutators used for producing changes in the current
necessary to the use and working of the apparatus described and represented in
the annexed Drawings, substantially as and for the purposes set forth.
3rd. The novel application to telegraphic or telephonic apparatus of a return
wire allowing numerous and simultaneous communications in the same system, and
obviating the use at the subscriber's end of the batteries now generally employed
in the telegraphic or telephonic systems, substantially as herein before described.
4th. The arrangement and modification of parts as described in reference to
Sheet 4 of the Drawings, by which the return wire may be omitted, substantially
as described.
5th. The moveable box with system of wedges permitting the displacement of a
telephone with the arrangement for securing the certainty of contact, substantially
as described.
6th. The general arrangement and combination of parts forming the improve-
ments in telegraphic or telephonic apparatus, substantially as hereinbefore described
and for the purposes set forth.
In witness whereof, I, the said Philip Middleton Justice, have hereunto set
my hand and seal, this Tenth day of August, in the year of our Lord