Improvements in Electric Telegraphs.
Year: 1886

page_text: Date of Application, 1st Dec., 1886
Complete Left, 3rd Oct., 1887
Complete Accepted, 15th Nov., 1887
PROVISIONAL SPECIFICATION.
Improvements in Electric Telegraphs.
I JAMES YATE JOHNSON of 47 Lincolns Inn Fields in the County of Middlesex
Gentleman do hereby declare the nature of this Invention which has been
communicated to me from abroad by Abner Mulholland Rosebrugh of 121 Church
Street in the City of Toronto in the Province of Ontario Canada Surgeon to be as
follows:-
According to this Invention upon the ordinary telegraph line are superimposed
secondary current signals without grounding any intermediate point and this is
accomplished by using the combination of one or more electro magnets with or without
a current manipulator in a primary voltaic circuit with a shunting circuit in which is
inserted a condenser or its equivalent an electric generator and a manipulator or Morse
key arranged to operate the secondary current telograph-"The receiver" in this
arrangement may be either in the shunting circuit or in the main line and the
generator may be either electro magnetic or magneto electric.
The secondary current manipulator or key may be arranged so that the electro
magnet or electro magnets of the electric generator is or are automatically either
short circuited or shunted from the induced current circuit when the said manipulator
is at rest. A differentially wound secondary current receiver may be used it being
counected in such a manner that it shall be neutral to voltaic currents with or without
being neutral to outgoing secondary currents and in some cases a magnetised core is
used for the secondary current receiver or the core of the electro magnet is kept
constantly charged by a weak voltaic current in the main line.
The receiver may also be inserted in a shunt around an electro magnet in the main
line and in said shunt a condenser may also be inserted.
A convenient form of generator is simply an electro magnet charged by a local
battery the operative current being the static discharge of said electro magnet when
the primary circuit is opened and said electro magnet generator may be inserted
either in the main line or in a derived or shunt circuit thereof.

page_text: In some case the receiver is differentially wound so as to be neutral to main line
currents but with one of its coils shunted by a condenser so as to make the remaining
coil responsive to induced currents.
When the receiver is in a derived or shunt circuit the receiver may be either an
electro magnet or it may be what is known as a "singing condenser." When
the receiver is placed in the main line an ordinary telephone receiver may be used.
Dated this 1st day of March 1886.
J. HENRY JOHNSON,
47, Lincoln's Inn Fields, London, W.C.,
Agent.

page_text: Improvements in Electric Telegraphs.
I, JAMES YATE JOHNSON, of 47 Lincolns Inn Fields in the County of Middlesex,
Gentleman, do hereby declare the nature of this Invention, which has been communi-
cated to me from abroad by Abner Mulholland Rosebrugh, of 121 Church Street in
the City of Toronto, Province of Ontario, Canada, Surgeon, and in what manner
the same is to be performed to be particularly described and ascertained in and
by the following statement:-
This Invention relates to improvements in multiplex Telegraphy and more
particularly to that form of multiple telegraphy where secondary or induced currents
Hitherto grounded
are superimposed upon the ordinary Morse telegraph circuit.
branch lines have been used to complete the secondary circuit, a condenser or other
inductor being used to prevent the grounding of the Morse circuit. This arrange-
ment is open to several objections, such as, for instance, the danger the line is in of
becoming grounded from faulty inductors or from lightning, and the liabilty of the
Morse instruments to disturbance from the static discharge of the inductors in said
grounded branch lines. The object of the present invention is to remove these
objections and this is accomplished by doing away with the grounded branch lines
and by substituting therefor means and devices for generating the secondary or
induced currents (used for signal purposes) directly in the main line of the Morse
circuit.
In carrying out this invention both the induced current generator and the induced
current receiver may be inserted directly in the main line of the Morse Circuit or one
or both may be inserted in a parallel or derived circuit. In the latter case the induced
current apparatus is inserted as a bridge around an electro-magnet in the main line
circuit. In some cases for a duplex receiver a differentially or doubly wound coil
is used connected so as to be neutral to Morse signals but responsive to induced
currents-This is accomplished by bridging one of said coils by means of a condenser
or an equivalent inductor.
In the accompanying diagrams Figures 1 and 3 represent both the generator and
receiver in the main line. Figures 2, 4, and 5 represent the generator in a parallel
or derived line. Figure 6 represents the receiver in a derived line. Figure 7
represents a doubly wound induced current receiver. Figures 8 and 9 represent the
bridging of Morse instruments.
In Figure 1, LL' is a telegraph line equipped at each end with battery and Morse
instruments. B is the battery, K the key, and R and R² electro-magnets, one of
which is the receiver. C is a condenser connected with the battery at c and with the
line at a.
G is the induced current generator, and T the induced current receiver,
both being in the main line. When the induced current generator is simply an
electro magnet it may be actuated by a local battery and key as shown in Figure 3,
LL being the telegraph line, and the electro-magnet used as an induced current
generator and operated by the local battery L, B, and the key K. By means of the

page_text: double contact points e and f, the local circuit is opened both at the front and at the
back contact points of the key. The wire g, connected with the back contact f, is
preferably made to tap the local battery at an intermediate point between e and m so
that the make and break ate and shall cause an unequal magnetization and
demagnetization of the electro-magnet G the object being to give alternately a strong
and a weaker induced current in the receiver so that when a magneto-telephone or its
equivalent is used as a receiver the ear may be able to distinguish between the down
and the up movement of the hand of the operator at the distant transmitter. The key
is connected with one pole of the electro-magnet G as shewn at c and the battery is
connected with the other pole of the said electro-magnet as at d―The electro-magnet. G
may also be bridged by a condenser as shewn at Cj.
In Figure 4 an electro-magnet is represented as being used for generating induced
currents in a parallel or bridging circuit. G is the electro-magnet. 1B the local
battery and K the double-pointed key. One pole of the generator G is connected
with the line at band the other pole is connected with the line at a. A condenser or
its equivalent is interposed in this bridging circuit as shewn at C. E. M. is an electro-
magnet in the telegraph line this electro-magnet may be a telegraph receiver while K
may be a key for opening and closing the telegraph line circuit.
In Figure is shewn another form of induced current generator according to this
invention, namely, an induction coil and rheotome. The primary circuit is actuated by
the local battery L B and is automatically interrupted by the rheotome Rh. The
secondary coil is in the bridging circuit in which a condenser (or its equivalent is
interposed. EM is an electro-magnet in the telegraph line which thus forms one
side of the parallel circuit. The electro-magnets EM in Figures 4 and 5 have a
high co-efficient of self-induction. The core of the induction coil may be used to
actuate the rheotome or a separate electro-magnet may, be used for this purpose.
When a separate electro-magnet is used to operate the rheotome the secondary wire
of the induction coil may be placed in the telegraph line circuit direct if desired.
In Figure 6 the induced current receiver is shewn in a bridging circuit.
L L is
the telegraph line with an electro-magnet E M. inserted therein. The parallel or
bridging circuit is formed hy the wires a and the condenser or inductor C and the
receiver T. A secondary current generator may also be inserted in this bridging
circuit, if desired, and may be inserted at any point as at X in said bridging circuit.
The receiver T may be a magneto-telephone a "singing condenser," or it may be a
specially constructed telegraph relay or it may be a galvanometer.
In Figure 7 L L represents a telegraph line with a doubly wound receiver E M
inserted therein. This receiver has two coils A and B on the same core and they are
connected in series. The coil A is preferably more elongated than coil B and it is
preferably wound with larger wire and has a larger co-efficient of self induction than
the coil B. The two coils are so adjusted and so connected that a primary current
traversing the two coils will fail to magnetize the soft iron core common to the two
coils. By bridging the elongated coil A with a condenser or its equivalent as at C
the coil B becomes responsive to induced currents on the line. The coil B may be
made to actuate a local circuit as indicated in the diagram or it may actuate a
telephone diaphragm or the two coils with or without a soft iron core may actuate a
galvanometer needle or it may actuate a recording instrument.
::
22
In Figures 1 and 2 is represented the method of connecting the inductors at
terminal stations while in Figures 8 and 9 is shewn the method of connecting the
inductors at intermediate or
way stations. In Figures 1 and 20 and are
inductors at terminal stations. One pole of the inductor is connected with the line
at a, and the other pole of said inductor is connected with the main line battery B at c.
The equipment is the same at each end of the telegraph line.
<
23
In Figures 8 and 9 the inductor forms a bridge around the electro-magnet E M
which latter may he at an intermediate or way telegraph station and E M Figure 9
is an electro-magnet in the line which may be an induced current receiver. The
inductor is connected with the main line at the point a and with the line battery at
the point c.
The inductor may be either a condenser or its electrical equivalent.

page_text: In using inductors for instance condensers for bridging Morse instruments those of
moderate capacity are used as it is not necessary for telegraph purposes that the
induction of the line shall be completely suppressed. The telegraph line works better
when inductors of only moderate capacity are used. Of course it is well known that
when inductors such as condensers are used for bridging Morse instruments they act
in a three fold capacity namely they assist in forming an artificial circuit independent
of the breaking of the Morse circuit by the Morse keys: they bridge the electro
magnets of the relays or other receivers and they diminish the induction on the line.
It is also to be understood that when an electro magnet having a high coefficient of
self induction is inserted in a telegraph line it forms a block to the passage of induced
currents; hence such electro magnets are used for diverting the induced currents and
for forming one side of the parallel circuits and hence when such electro magnets are
bridged by condensers or other inductors a double circuit is formed the former for the
primary currents and the latter for the induced currents-From this it will be seen
that an induced current may be superimposed upon a telegraph line and used as a
duplex or multiplex telegraph without grounding said induced current circuit.
In the various diagrams where necessary the parts which correspond with those
described with reference to other of the diagrams are marked with the same letters
of reference and require no further description.
Having now particularly described and ascertained the nature of this Invention
and in what manner the same is to be performed I declare that what I claim is.
First In telegraphs for simultaneous working the employment of means for
generating the secondary or induced currents directly in the main line substantially
as herein before explained.
Second-In an electric telegraph line with means for transmitting and receiving
voltaic or primary telegraph signals the combination of moans and devices for
generating and receiving induced current signals on the line itself without grounding
said induced current circuit substantially as and for the purpose hereinbefore set
forth.
Third The combination with an electric telegraph line and means for transmitting
and receiving voltaic signals or signals of electro magnets for transmitting and
receiving induced current signals in the line itself substantially as herein before
described.
Fourth-The combination with an electric telegraph line and means for transmitting
and receiving voltaic signals or signals of electro magnets and bridging circuits for
the purpose of forming parallel circuits in the said telegraph line substantially as
hereinbefore described.
Fifth The combination with an electric telegraph line and means for transmitting
and receiving voltaic or primary telegraph signals of an electro magnet having a high
coefficient of self induction with a bridging circuit in which a condenser or its
electrical equivalent is interposed for the purpose of forming an induced current
circuit as a duplex circuit upon said telegraph line substantially as herein before
described.
Sixth The combination with an electric telegraph line and means for transmitting
and receiving voltaic or primary telegraph signals of means for bridging and
controlling the induction from the telegraph instruments and means for transmitting
and receiving induced current signals as a duplex circuit upon the said telegraph line
without grounding the said induced current circuit substantially as herein before
described.
Seventh-The combination with an electric telegraph line (for the purpose of
forming an induced current receiver that shall be neutral to primary electric signals)
of two coils and a condenser or its equivalent the said condenser or its equivalent
forming a bridge to one of said coils substantially as herein before described.
Eighth An induced current receiver formed by an electro magnet with two coils
one of which coils has a coefficient of self induction high with respect to the other
coil and a condenser or its equivalent forming a bridge around the coil with a high

page_text: coefficient of self induction substantially as and for the purpose herein before set
forth.
Ninth The several arrangements in connection with telegraphs substantially as
herein before described and respectively illustrated by the several accompanying
diagrams.
Tenth For the purpose of utilizing the static discharge of an electro magnet for
signalling purposes the combination of an electro magnet, a local battery and a double
pointed key or manipulator substantially as described.