IMPROVEMENTS IN ELECTRIC TELEGRAPHS
Year: 1877

page_text: LETTERS PATENT to Johann Carl Ludwig Loeffler and Richard Williain
Henry Paget Higgs, both of No. 12, Queen Anne's Gate, Westminster, in the
County of Middlesex, for the Invention of "IMPROVEMENTS IN ELECTRIC
TELEGRAPHS."
aled the 13th April 1877, and dated the 20th February 1877.
PROVISIONAL SPECIFICATION left by the said Johann Carl Ludwig Loeffler
and Richard William Henry Paget Higgs at the Office of the Commissioners
of Patents on the 20th February 1877.
JOHANN CARL Ludwig LOEFFLER and RICHARD WILLIAM HENRY PAGET HIGGS,
both of No. 12, Queen Anne's Gate, Westminster, in the County of Middlesex.
"IMPROVEMENTS IN ELECTRIC TELEGRAPHS."
In signalling by electric telegraph over land lines or cables of considerable length
the impulses sent from the one end of the line arrive at the other end in such a
manner that when they are caused to succeed each other rapidly they are apt to
produce signals running into one another, or otherwise indistinct, or to fail to
produce signals, and thus the rapidity of transmission is limited. Various
means are applied for remedying this defect with a view to obtain greater
distinctness of signals, and to permit greater rapidity of transmitting them.
Our Invention relates to methods of operating and arranging connections and
appliances for this purpose, and also to arrangements for duplex telegraphing, and
to instruments and codes suitable for rapid communication.
By means of a bridge arrangement of suitably regulated resistances we place the
receiving instrument under a definite difference of potential derived from a battery
or other source of electricity placed at the receiving station in the battery branch of
the bridge arrangement, but so that the instrument does not operate for signalling
except when this difference of potential is varied by an impulse caused by action at
thie sending station.
.
The arrangement for this purpose may be varied; one such an arrangement is
shewn diagrammatically at Fig. 1 of the accompanying Drawings, and is of the
following character:-The line or cable L is connected to the one terminal of the
receiving instrument I; and also through a resistance R permanently to one pole of-

page_text: a battery B or other source of electricity, the other pole of which is connected to
earth at E. The first-named pole of B. is connected through a resistance S to the
other terminal of the instrument I, which is also connected through a resistance T
to earth. The resistances R, S, T, are so adjusted to each other and to the battery
power, and also to the resistance of the line while the sending instrument is
quiescent, as to bias the receiving instrument to such an extent that when impulses
are transmitted from the sending station either the instrument will not be acted
on by the beginning and ending portions of those impulses during which portions
the force gradually increases and decreases, or that so much force will be added to
these portions of the impulses that the receiving instrument will begin to be
influenced nearly at the beginning, and continue to be influenced nearly up to the
termination of each impulse.
When applying our arrangement to a line having considerable capacity, such
as a cable, we sometimes connect to the branch S a condenser or a combination of
For the condensers may be sub-
condensers, as shewn at C in the diagram, Fig. 2.
stituted equivalent electro-magnets.
A bridge arrangement of like kind may be employed without a separate battery
in the manner shewn diagrammatically at Fig. 3. In this case the resistance Rand
S are at their junction connected to earth E, and a condenser or combination of
condensers C is introduced in the branch S.
In the arrangement, shewn in Figs. 1 and 2, the instrument I and the battery B
may change places, and in the arrangement shewn in Fig. 3 the instrument I may
be transferred to the branch b, the resistances being suitably adjusted.
Arrangements, such as we have described, may be employed in combination
with other known arrangements for the same purpose, and condensers, induction
coils, electro-magnets, batteries, and other known appliances may be introduced in
the several circuits..
"
Fig. 4 shews diagrammatically an arrangement for the purpose mentioned above,
in which we combine the four branches of a bridge with the receiving instrument,
a combination which we will hereafter terin a local bridge." In this arrangement
the receiving instrument I is connected by both terminals to the branches a, b, c, d,
which are equal or so proportioned to one another that the instrument is not
affected by any current transmitted by the cable or line when a condenser F is not
connected to one of the branches a, b, c, or d; but when such a condenser as F is
connected to one of the four branches the receiving instrument is actuated only by
Under certain conditions, by avoiding
the charge and discharge of the condenser.
exact balance of this bridge system, permanent currents may be made to aid the
condenser in actuating the receiving instrument. By proper adjustment of the
capacity of the condenser to that of the line, so that the condenser charge affects
the receiving instrument for a less time than the charge or discharge of the cable
would affect it, increased [speed is obtained. As the receiving instrument is not
directly included in the line circuit its coil may be wound so as to give increased
delicacy, as, for example, by employing a greater number of convolutions than it
would be possible to use in direct circuit with the line without great sacrifice of
speed. For the condenser shewn in Fig. 4 may be substituted an electro-magnet M
in one branch of the local bridge, as shewn diagrammatically in Fig. 5. For the
electro-magnet its equivalent may be substituted, as for example, primary and
secondary circuits of induction coils.
In the arrangements above described additional condensers or their equivalents
may be employed in the several branches of the bridge. Instead of employing a
bridge arrangement, as described above, we sometimes use for a like purpose a
differentially wound receiving instrument, placing a condenser in connection there-
with, so as to cause the instrument to be affected, not by the line current, but only.
by the condenser.
A bridge arrangement somewhat similar to that described above with reference
to Figs. 1, 2, and 3, has been employed for duplex telegraphing, but in that case it
is applied for the purpose of preventing the receiving instrument from acting under

page_text: influence of signalling currents transmitted from the receiving end of the line, and
consequently the resistances and connections are arranged to maintain different
electrical conditions.
For duplex telegraphing we employ the "local bridge" combined with known
arrangements for duplex working; one such combined arrangement is shewn
diagrammatically by Fig. 6. In this case the "local bridge" enclosing the instru
ment I is connected at a and b to the branches c and d of a duplexing bridge, and
also at a to the line wire L and at b to an artificial line e, f, which may consist of
condensers, as shown in the Figure. The junction of c and d is connected to the
operating key K. commanding the poles of the battery B. In this arrangement the
receiving instrument is acted on as described with reference to Fig. 4, when currents
are transmitted to it from the line, but it is not affected by currents transmitted
from the key K to the line.
Another combination for this purpose is shewn diagrammatically by Fig. 7, in
which case the "local bridge" is connected at one apex C to the line L, and at the
other apex A to the battery B. These two connections are also connected through
adjustable resistances S¹, S, to the key K.
According to another arrangement shewn diagrammatically by Fig. 8, the "local
bridge" is connected at one apex to the line, and at the opposite apex by an
adjustable resistance W to earth. In one branch of the bridge is an electro-
magnet E surrounded by a coil G, connected to the key K and the resistance W, so
that when the key is depressed to complete circuit with the battery B, the
self-induced current of the electro-magnet E is neutralised as far as concerns the
instrument I by the current of mutual induction between the coil G and the coil
of E. When a condenser is used the arrangement may be like that shewn diagram-
matically by Fig. 9, where C is a double condenser with two sets of inducing leaves,
so that on depressing the key the effect of the charge communicated to one set of
leaves is neutralised by the effect of the charge communicated to the other set of
leaves, and there is no resultant action on the receiving instrument I.
Also the arrangement shewn by Fig. 9 may be modified, as shewn diagram-
matically by Fig. 10, where a lever attached to the key K actuates a local circuit so
as to neutralise on the receiving instrument I the effect of the current sent to the
line.
The arrangement shewn in Fig. 10 may be modified, as shewn in Fig. 11, where
instead of employing a local circuit the battery B is connected through a resistance R
to earth.
In the bridge arrangements above described, although for the sake of simplicity
only one battery or other known appliance is shewn in the diagrains, it is obvious
that several such batteries or appliances might be employed as is well understood;
also any receiving instrument of known construction may be employed. We prefer,
however, to use an instrument similar in some respects to that described in the
Specification to a Patent granted to C. W. Siemens, on the 25th June, 1872,
No. 1919, and shewn in Figs. 9, 10, and 11 of the Drawings annexed to the said
Specification.
In the modified form of this instrument which we prefer to use, instead of
employing a single coil mounted on an axis, as shewn in these Figures, we divide
the coil into two parts and place them opposite to one another, connecting them
together by a cross bar or frame, and suspending the whole by one or more wires or
fibres. The coils thus suspended in balance are caused to take an angular position
to either hand by the passage of electrical currents through them, and are brought
back to a position of rest when the disturbing influence ceases, and these angular
movements of the coils may be utilised in any known manner for signalling or for
making or breaking contact for another circuit. Instead of using two coils in this
manner & single coil with a counterbalance may be mounted as above described.
One mode of applying the movements of the coil or coils above referred to for
the production of visible signals is as follows:-To the coils or to the arm con-
necting them we connect by means of fibres the two arms of a conducting lever,

page_text: which for lightness we prefer to be of aluminum, and which is itself pivotted on a
fibre. The one end of this lever moves over a conducting plate which is connected
to the one electrode of an induction coil, and the other end moves over a strip of
prepared paper or other recording surface, which is advanced in the ordinary way
over a roller or pad connected to the other electrode of the induction coil. The
lever being made to oscillate in accordance with the movements of the coils, a spark
passes from the plate to its one end, and from its other end to the paper or recording
surface, making a mark thereon, and the vibratory motion of the marking point
combined with the advance of the recording surface produces on the latter a wave
line by the form of which the signals are distinguished as is well understood. By
thus causing the electricity to act at both ends of the lever there is no disturbance
of its equilibrium by electrostatic repulsion.
Another mode in which the movements of the coil or coils above referred to may
be applied for the purpose of recording signals in the Morse or analogous characters
is as follows-To the coils or their connecting arm we attach a rigid arm, near the
end of which is fitted a sliding pin, and at a little distance beyond each end of the
pin is fixed a contact point, these points being connected in the usual way with a
local circuit. When the coils are caused to oscillate the arm carrying the sliding
pin oscillates with them, bringing either end of the pin in contact with one or other
of the contact points, the pin being thereby caused to slide more or less, according
to the extent of the oscillation, so that after having made contact in the one
direction, immediately on a cessation or reversal of line current the contact is
broken and the pin is in position ready to make contact in the other direction.
Instead of using one arm carrying the sliding pin, two arms may be employed to
act on either end of a pin which can slide in or on a stationary conductor connected
to the local circuit.
In the visible signals of the Morse and other like codes, the dots, dashes, or other
marks employed to constitute by their various successions and combinations
different letters or other signals are separated by blank intervals, or in some kinds
of instruments, as for instance, the syphon recorder, by certain marks indicative
merely of separation. The production of each such blank interval or separation
mark occupies a portion of time, which may be considered to be lost for the purpose
of signalling. In order to avoid this loss of time we produce the compound marks
constituting signals by reversals of current or changes of potential immediately
succeeding each other, in such a manner that each current or change of potential,
or each combination of currents producing one change of potential at the receiving
station is utilised for the production of a significant signal, and that these signals
are distinguished from each other notwithstanding their immediate succession.
For this purpose we produce the marks alternately in two parallel lines, so that no
interval of space longitudinally is required between them, and no appreciable
interval of time is occupied in passing from one mark to the next in order. By
arranging the code employed so that regard is had to the position laterally of the
several marks constituting a letter or signal we are enabled to double the number
of available distinct signals, and can consequently select for those most generally
used such of the combinations as consist of the least number of marks, or as can be
most rapidly produced. In order that this may be more clearly understood as well
as the features in which signals of the kind described are distinguished from each
other, and from those of the ordinary codes, we have shewn at Fig. 12 the alphabet
according to the Morse system; at Fig. 13, the same alphabet, according to what is
known as the Steinheil code, in which dots in a separate line are substituted for
dashes; and at Fig. 14 we have shewn a code for the alphabet in which the
lateral position of each of the marks constituting a letter is taken into account,
and in which there is no longitudinal interval between one mark and the next in
succession. Not only may dots and dashes be thus combined, but also dots and
dashes, or dots alone may be combined with longitudinal spaces of equal or varying
lengths, themselves representing constituent parts of a letter or other signal. At
Fig. 15 we have shewn such a code for the alphabet consisting of combinations of

page_text: dots, dashes, and spaces, each of the latter being of the length of a dot, and
occurring only when marks follow each other in the same line; at Fig. 16 we have
shewn a code consisting of dots combined with spaces employed only when dots
follow each other on the same line; and at Fig. 17 a code consisting of dots
combined with spaces, each having the length of a dot, and occurring when the
dots follow each other in the same or in alternate lines.
It is obvious that other combinations might be employed, as for example, dots or
dots and dashes combined with spaces of various lengths, but we prefer the com-
bination of dots and dashes without intervals, as shewn at Fig. 14, as we can
then employ a very short blank interval to indicate the separation of one letter
from another, preventing also the possibility of any two constituent parts of a
letter running into one another.
For producing marks on two lines, as above described, various instruments
having double styles may be employed, and instead of employing positive and
negative currents similar effects may be produced by a rise and fall of potential in
the line.
:
For transmitting alternately positive and negative currents by successive similar
actions of a manipulator we sometimes employ a key, under which is mounted a
rocking lever pivotted on a vertical axis nearly under the axis of the key, and
extend the key backwards beyond its own axis. On the under side of the
front arm of the key is a V shaped projection for making contact with either of
two insulated sloped pieces projecting upwards on the front arm of the rocking
lever, the one of which projections is connected for a positive and the other for a
negative current. On the under side of the back arm of the key there is also a'
V shaped projection, and under it there is a V shaped piece projecting from the
back arm of the rocking lever. When the key is pressed down in front, its
V projection makes contact with one or other of the sloping pieces on the rocking
lever, causing, for example, a positive current to be transmitted to linc, but at the
same time acting on the sloped surface of the projection, it causes the front of the
rocking lever to move towards one side. When the key is released so that its front
arm is caused by a spring to rise, breaking contact, its back arın descends, and the
sloping projection on it acting upon the projection on the back arm of the rocking
lever causes that lever to move still farther in the direction in which it had been
moved by the act of contact making, and so to bring uuder the front of the key the
negative contact piece. Thus on the next depression of the key a negative current
is transmitted, and at the same time the rocking lever is moved partly back, and
when the key rises it is moved wholly back, presenting again the positive contact
piece for the next action.
Although we have above described our improvements in telegraphic signal codes
as applied in the case where visible marks, such as dots or dashes, are produced, it
nay readily be understood that a similar system can be applied for simplifying and
abbreviating signals given by deflections of needles or inovements of beams of
light, or by sounds of different tone, by dispensing with the blank intervals or their
equivalents usually presented, and making the indications follow each other in close
succession.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Johann Carl Ludwig Loeffler and Richard William Henry Paget
Higgs in the Great Seal Patent Office on the 20th August 1877.
JOHANN CARL LUDWIG LOEFFLER and RICHARD WILLIAM HENRY PAGET HIGGS,
both of No. 12, Queen Anne's Gate, Westminster, in the County of Middlesex.
IMPROVEMENTS IN ELECTRIC TELEGRAPHS."
"
In signalling by electric telegraph over land lines or cables of considerable length
the impulses sent from the one end of the line arrive at the other end in such a

page_text: manner that when they are caused to succeed each other rapidly they are apt to
produce signals running into one another, or otherwise indistinct, or to fail to
produce signals, and thus the rapidity of transmission is limited. Various means
are applied for remedying this defect with a view to obtain greater distinctness of
signals, and to permit greater rapidity of transmitting them.
Our Invention relates to methods of operating and arranging connections and
appliances for this purpose, and also to arrangements for duplex telegraphing, and
to instruments and codes suitable for rapid communication.
By means of a bridge arrangement of suitably regulated resistances we place the
receiving instrument under a definite difference of potential derived from a battery
or other source of electricity placed at the receiving station in the battery branch
of the bridge arrangement, but so that the instrument does not operate for
signalling, except when this difference of potential is varied by an impulse caused
by action at the sending station.
The arrangements for this purpose may be varied; one such an arrangement is
shewn diagrammatically at Fig. 1 of the accompanying Drawings, and is of the
following character:-The line or cable L is connected to the one terminal of the
receiving instrument I, and also through a resistance R permanently to one pole of
a battery B or other source of electricity, the other pole of which is connected to
earth at E. The first-named pole of B is connected through a resistance S to the
other terminal of the instrument I, which is also connected through a resistance T
to earth. The resistances R, S, T, are so adjusted to each other and to the battery
power, and also to the resistance of the line while the sending instrument is
quiescent, as to bias the receiving instrument to such an extent that when impulses
are transmitted from the sending station either the instrument will not be acted on
by the beginning and ending portions of those impulses, during which portions the
forces gradually increases and decreases, or that so much force will be added to
these portions of the impulses that the receiving instrument will begin to be
influenced nearly at the beginning and continue to be influenced nearly up to the
termination of each impulse.
When applying our arrangement to a line having considerable capacity, such as
a cable, we sometimes connect to the branch S a condenser or combination of
condensers, as shewn at C in the Diagram, Fig. 2. For the condenser may be sub-
stituted equivalent electro-magnets.
A bridge arrangement of like kind may be employed without a separate battery
in the manner shewn diagrammatically at Fig. 3. In this case the resistances Ⓡ
and S are at their junction connected to earth E, and a condenser or combination
of condensers C is introduced in the branch S.
In the arrangement shewn in Figs. 1 and 2 the instrument I and the battery B
may change places; and in the arrangement shewn in Fig. 3 the instrument I may
be transferred to the branch b, resistances being properly adjusted.
Arrangements such as we have described may be employed in combination with
other known arrangements for the same purpose, and condensers, induction coils,
electro-magnets, batteries, and other known appliances may be introduced in the
several circuits.
Fig. 4 shews diagrammatically an arrangement for the purpose mentioned above,
in which we combine the four branches of a bridge with the receiving instrument,
a combination which we will hereafter term a "local bridge." In this arrange-
ment the receiving instrument I is connected by both terminals to the branches
a, b, c, d, which are equal or so proportioned to one another that the instrument is
not effected by any current transmitted by the cable or line L when a condenser F
is not connected to one of the branches a, b, c, or d. But when such a condenser
as F is connected to one of the four branches the receiving instrument is actuated
only by the charge and discharge of the condenser. Under certain conditions, by
avoiding exact balance of this bridge system, permanent currents may be made to
aid the condenser in actuating the receiving instrument. By. proper adjustment of
the capacity of the condenser to that of the line, so that the condenser charge effects

page_text: the receiving instrument for a less time than the charge or discharge of the cable
would effect it, increased speed is obtained. As the receiving instrument is not
directly included in the line circuit its coil may be wound so as to give increased
delicacy, as for example, by employing a greater number of convolutions than it
would be possible to use in direct circuit with the line without great sacrifice of
speed. For the condenser shewn in Fig. 4 may be substituted an electro-magnet M
in one branch of the "local bridge," as shewn diagrammatically at Fig. 5. For the
electro-magnet its equivalent may be substituted, as for example, primary and
secondary circuits of induction coils.
In the arrangements above described additional condensers, or their equivalents,
may be applied in the several branches of the bridge. Instead of employing a
bridge arrangement, as described above, we sometimes use for like purpose a
differentially wound receiving instrument, placing a condenser in connection there-
with, so as to cause the instrument to be effected not by the line current but only
by the condenser.
A bridge arrangement somewhat similar to that described above with reference
to Figs. 1, 2, and 3, has been employed for duplex telegraphing, but in that case it
is applied for the purpose of preventing the receiving instrument from acting under
influence of signalling currents transmitted from the receiving end of the line, and
consequently the resistances and connections are arranged to maintain different
electrical conditions.
For duplex telegraphing we employ the “local bridge" combined with known
arrangements for duplex working. One such combined arrangement is shewn
diagrammatically by Fig. 6. In this case the "local bridge" enclosing the instru
ment I is connected at a and b to the branches c and d of a duplexing bridge, and
also at a to the line wire L, and at b to an artificial line e, f, which may consist of
condensers, as shewn in the Figure. The junction of c and d is connected to the
operating key K commanding the poles of the battery B. In this arrangement the
receiving instrument is acted on as described with reference to Fig. 4 when currents
are transmitted to it from the line, but it is not affected by currents transmitted
from the key K to the line.
Another combination for this purpose is shewn diagrammatically by Fig. 7, in
which case the "local bridge" is connected at one apex C to the line L, and at the
other apex A to the battery B. These two connections are also connected through
adjustable resistances S¹, S, to the key K.
According to another arrangement, shewn diagrammatically by Fig. 8, the "local
bridge" is connected at one apex to the line, and at the opposite apex by an adjust-
able resistance W to earth. In one branch of the bridge is an electro-magnet E
surrounded by a coil G connected to the key K. and the resistance W, so that when
the key is depressed to complete circuit with the battery B the self induced current
of the electro-magnet E is neutralized as far as concerns the instrument I by the
current of neutral induction between the coil G and the coil of E. When a con-
denser is used the arrangement may be like that shown diagrammatically by
Fig. 9, where C is a double condenser with two sets of inducing leaves, so that on
depressing the key the effect of the charge communicated to one set of leaves is
neutralised by the effect of the charge communicated to the other set of leaves, and
there is no resultant action on the receiving instrument. I.
Also the arrangement shewn by Fig. 9 may be modified, as shewn diagram-
matically by Fig. 10, where a lever attached to the key K actuates a local circuit,
so as to neutralize on the receiving instrument I the effect of the current sent to
the line.
.
The arrangement shewn in Fig. 10 may be modified, as shewn in Fig. 11, where;
instead of employing a local circuit the battery B is connected through a resistance R
to earth.
In the bridge arrangements above described, although for the sake of simplicity
only one battery or other known appliance is shewn in the diagrams, it is obvious
that several such batteries or appliances might be employed, as is well understood:

page_text: Also any receiving instrument of known construction may be employed, we
prefer however to use an instrument similar in some respects to that described in
the Specification to a Patent granted to C. W. Siemens, on the 25th June, 1872,
No. 1919, and shewn in Figs. 9, 10, and 11 of the Drawings annexed to the said
Specification.
In the modified form of this instrument, which we prefer to use, instead of cm-
ploying a single coil mounted on an axis, as shewn in these Figures, we divide the
coil into two parts, and place them opposite to one another, connecting them
together by a cross bar or frame, and suspending the whole by one or more wires or
fibres. The coils. thus suspended in balance are caused to take an angular
position to either hand by the passage of electrical currents through them, and
are brought back to a position at rest when the disturbing influence ceases, and
these angular movements of the coils may be utilised in any known manner by.
signalling or for making or breaking contact for another circuit. Instead of using
two coils in this manner, a single coil with a counterbalance may be mounted, as
above described.
Fig. 18 represents a plan; Fig. 19, a side view, and Fig. 20, a part vertical section
of a relay constructed in this manner.
E is an electro-magnet of which the one pole A is extended in the form of a ring
into a recess formed in the other. pole B, which is hollowed to receive this ring.
C, C, are two coils balancing each other and embracing the ring, but with sufficient
clearance to move freely along it. These coils are fixed to a frame F, which is
suspended by two fibres from a screw pin D, by turning which the coils may be
raised or lowered without lateral movement of the fibres. In order to centre the
coils, the axis G of their frame is passed through a hole in an arm H, and its point
works in a jewelled hole in the top of the pole B. A lug I projecting from the
frame F carries a platinum contact pin J between the two adjustable contact screws
K and L. The local circuit is formed from the connecting wire M through the
frame F, the lug I, with its pin J, and the contact screws K and L, in the usual
manner. The line current is led by the connecting wires N and O into the coils
C, C, and thence to earth through the connecting wires P and Q if the instrument
is arranged for working in the ordinary manner with its coils connected parallel.
Instead of fixing the contact pin J in the lug I, we prefer to fix it so that it can
slide freely as a shuttle in the hole in I. When the coils C, C, are caused to
oscillate in the one direction, the lug I oscillating with them brings one end of the
shuttle J in contact with one of the contact screws, for example, K and the coils
may then continue their movement in the same direction, the lug I sliding over J,
which remains at rest with its opposite end at a very small distance from the
other contact screw L. On a cessation, reversal, or change of potential of the line
current, the shuttle J is moved away from K, and up to L, thus immediately breaking
contact on the one side and making contact on the other side, and this result is
obtained by the use of the sliding shuttle J, whatever be the extent of oscillation of
the coils C, C, provided that it is not less than the distance of either end of J from
the one contact screw when its other end is bearing against the other contact screw.
The lug I may be fixed on the stationary framing of the instrument, and the
contact screws K and L may be fixed on the coil frame F, and the shuttle J fitted
in a hole of I, when so arranged, will operate in a manner similar to that
described above. A sliding contact shuttle, such as J, may be applied to the
vibrating tongues of relays of other kinds than that shewn by Figs. 18, 19, and 20,
for the same purpose, as may be readily understood. Instead of employing two
coils C, C, balancing each other, a balance weight may be substituted for one of
these, but we prefer to employ the two coils, as shewn in the Drawings.
In the visible signals of the Morse and other like codes, the dots, dashes, or other
marks employed to constitute by their various successions and combinations
different letters or other signals, are separated by blank intervals; or in some kind
of instruments, as for instance, the syphon recorder, by certain marks indicative
merely of separation. The production of each such blank interval or separation

page_text: mark occupies a portion of time which may be considered to be lost for the purpose
of signalling. In order to avoid this loss of time, we produce the compound marks
constituting signals by reversals of current or changes of potential immediately
succeeding each other in such a manner that each current or change of potential, or
each combination of currents producing one change of potential at the receiving
station is utilised for the production of a significant signal, and that these signals
are distinguished from each other notwithstanding their immediate succession.
For this purpose we produce the marks alternately in two parallel lines, so that no
interval of space longitudinally is required between them, and no appreciable in-
terval of time is occupied in passing from one mark to the next in order. By arranging
the code employed, so that regard is had to the position laterally of the several
marks constituting a letter or signal, we are enabled to double the number of
available distinct signals, and can consequently select for those most generally used,
such of the combinations as consist of the least number of marks, or as can be most
rapidly produced. In order that this may be more clearly understood, as well as
the features in which signals of the kind described are distinguished from each other
and from those of the ordinary codes, we have shewn at Fig. 12, the alphabet
according to the Morse system; at Fig. 13, the alphabet according to what is known as
the Steinheil code, in which dots in a separate line are substituted for dashes; and
at Fig. 14 we have shewn a code for the alphabet in which the lateral position of
each of the marks constituting a letter is taken into account, and in which there is
no longitudinal interval between one mark and the next in succession. Not only
may dots and dashes be thus combined, but also dots and dashes, or dots alone may
be combined with longitudinal spaces of equal or varying lengths, themselves
representing constituent parts of a letter or other signal. At Fig. 15 we have
shewn such a code for the alphabet, consisting of combinations of dots, dashes, and
spaces, each of the latter being of the length of a dot, and occurring only when
marks follow each other in the same line. At Fig. 16 we have shewn a code
consisting of dots combined with spaces employed only when dots follow each other
in the saine line; and at Fig. 17 a code consisting of dots combined with spaces,
each having the length of a dot, and occurring when the dots follow each other in
the same or in alternate lines. It is obvious that other combinations might be
employed, as for example, dots or dots and dashes combined with spaces of various
lengths, but we prefer the combination of dots and dashes without intervals, as
shewn at Fig. 14, as we can then employ a very short blank interval to indicate
the separation of one letter from another, preventing also the possibility of any
two constituent parts of a letter running into one another.
For producing marks on two lines, as above described, various instruments
having double styles may be employed, and instead of employing positive and
negative currents similar effects may be produced by a rise and fall of potential in
the line.
For transmitting alternately positive and negative currents by successive similar
actions of a manipulator we sometimes employ a key, under which is mounted a
rocking lever pivotted on a vertical axis nearly under the axis of the key, and
extend the key backwards beyond its own axis. On the under side of the front arm
of the key is a V shaped projection for making contact with either of two insulated
sloped pieces projecting upwards on the front arm of the rocking lever, the one of
which projections is connected for a positive and the other for a negative current.
On the under side of the back arm of the key there is also a V shaped projection,
and under it there is a shaped piece projecting from the back arm of the rocking
lever. When the key is pressed down in front its V projection makes contact with
one or other of the sloping pieces on the rocking lever, causing, for example, a
positive current to be transmitted to line, but at the same time acting on the sloped
surface of the projection, it causes the front of the rocking lever to move towards
one side. When the key is released so that its front arm is caused by a spring to
rise, breaking contact, its back arm descends, and the sloping projection on it, acting

page_text: upon the projection on the back arm of the rocking lever, causes that lever to move
still farther in the direction in which it had been moved by the act of contact
making, and so to bring under the front of the key the negative contact piece.
Thus on the next depression of the key a negative current is transmitted
and at the same time the rocking lever is moved partly back, and when the key
rises it is moved wholly back, presenting again the positive contact piece for the
next action.
Fig. 21 represents a side view, Fig. 22 a front view of an alternating key
constructed in this manner, and Fig. 23 represents a plan of the rocking lever. L is
the key, having shaped studs W and V near each end on the under side of the
key; P and N are sloping contact pieces insulated from each other on the front end
of the ebonite rocking lever R; B is a V shaped piece on the back end of the
lever R. When the key L is depressed in front, the stud W makes contact with one
or other of the pieces, as for example P, and acting on its slope pushes the front of
the lever R towards the right, the stud V being at that time clear above B, which
by the movement of R is moved in the opposite direction towards the left. On
releasing the key L the stud V descending along the sloping left side of B, pushes
it farther towards the left, thus bringing the front of R farther towards the right,
and presenting the other contact piece N to receive the next contact of W, when the
key L is again depressed. The positive and negative poles of a battery being
connected to the pieces P and N, and the middle of the battery being put to earth,
and the line, which may be considered as to earth at the other end, being connected
to the lever L by successive depressions of the key, alternate currents are thus sent
into the line. The pieces N and P instead of being connected to the opposite poles
of one battery might obviously be connected to poles of different batteries or other
sources of electric power, and thus successive depressions of the key L, instead of
producing currents alternating in sign, might be applied to produce currents
alternating in intensity or other quality.
Although we have above described our improvements in telegraphic signal codes
as applied in the case where visible marks, such as dots or dashes, are produced, it
may be readily understood that a similar system can be applied for simplifying and
abbreviating signals given by deflections of needles or movement of beams of
light, or by sounds of different tone by dispensing with the blank intervals or
their equivalents usually presented, and making the indications follow each other in
close succession.
Having thus described the nature of our said Invention, and in what manner the
same is to be performed, we claim :-
First. Connecting the receiving instrument of a telegraphic line by means of a
bridge arrangement of suitably regulated resistances, combined or not with con-
densers or their electrical equivalents, so disposed and adjusted that the instrument
does not operate for signalling except when an electrical impulse is transmitted
from the sending station, substantially in the manner illustrated by Figs. 1, 2 and 3
of the accompanying Drawings and for the purposes herein set forth.
Second. Connecting the receiving instrument of a telegraph line by means of a
bridge arrangement of suitably regulated resistances, combined with condenser or
their equivalents, so disposed and adjusted that the instrument is operated upon by
condensers or their equivalents, which are acted on by currents transmitted from
the sending station, substantially as illustrated by Figs. 4 to 11 inclusive of the
accompanying Drawings.
Third. The use for telegraphic signalling of a code consisting of combinations of
dots, dashes and intervals, or of any of those arranged in two parallel lines in such
a manner that between the successive marks constituting each symbol there is no
interval of space that is not significant, substantially as herein described.
Fourth. The construction of relays wherein balanced coils suspended in circular
magnetic fields, work arms or tongues between contacts, substantially as herein
described with reference to Figs. 18, 19, and 20 of the accompanying Drawings.

page_text: Fifth. Fitting the oscillating tongue of a relay with a sliding shuttle so arranged
as to make contact on either side by a small movement without limiting the stroke
of the tongue, substantially as herein described.
Sixth. The application to a telegraph key of a rocking lever having inclines so
arranged that successive depressions of the key cause contacts to be made for
transmitting electric currents from separate sources alternately, substantially as
herein described with reference to Figs. 21, 22, and 23 of the accompanying
Drawings.
In witness whereof, I, the said Richard William Henry Paget Higgs, have
hereunto set my hand and seal, this Eighteenth day of August, in the year
of our Lord One thousand eight hundred and seventy-seven.
RICHARD WILLIAM HENRY PAGET HIGGS. (LS.)