IMPROVEMENTS IN TELEGRAPHS to be as follows:
Year: 1885

page_text: I, CHARLES LANGDON-DAVIES of 110 Cannon Street in the City of London,
Electrician do hereby declare the nature of my invention for "IMPROVEMENTS IN
TELEGRAPHS to be as follows:-
"
According to this invention telegraphic signals are transmitted by means of
induction coils furnished with vibrators and in conjunction with electrophones in
such a manner as to permit of one or more electrophonic transmissions simul-
taneously with the ordinary telegraphs.
I usually construct the transinitter coil in three parts-First-the primary
which may be made of single or multiple wire and advantageously of the latter. It
includes the battery, the break or breaks hereafter described and the key. 2nd The
secondary composed of one of my patent multiple wires, of two strands, one end of
cach strand being carried to the line or line and earth on either side of a sufficient
resistance, the other end being insulated. 3rd A tertiary consisting of a circuit of
insulated wire including the receiver and key.
:
In some cases the receiver is placed in the line wire and the tertiary circuit
dispensed with.
The break is adjusted to produce the number of vibrations necessary to make the
note or tone required in the receiver, or made adjustable to various notes by means
of springs or slides or contact screws in various positions. It is actuated in the
ordinary way by a soft iron core and sometimes I place a break at each end of the
core. When it is not convenient to produce the required number of vibrations in
I use a break actuated by mechanical means.
this way
The transmitting key may be an ordinary Morse key, the two front contacts of
which make and break the primary while the two back contacts simultaneously
break and make the tertiary, so, that the receiver at the trausinitting station is
always cut out when a signal is leaving. In this case dots and dashes are
represented by short and long contacts of the key producing short or long sounds
at the receiving station. The sending operator can ascertain that his signals are
leaving, either by listening to the soft sound of the break, or looking at the spark
of the contact screw.
Or the key may be constructed. to work right and left like the key of an
ordinary needle instrument and the transmitter made to produce two sounds

page_text: (representing right and left signals) by arranging breaks at each end of the core,
of different adjustment, one actuated only by the right and the other only by the
left hand movement of the key. Or the necessary difference is made with only one
break, by placing two contact screws in different positions against the break, each
screw actuated by a different movement of the key. Or a sufficient difference may
often be made by a difference in the shape of the contacts of the key. If for
instance the right hand contact be made a quarter of an inch in diameter and the
left hand contact a knife edge, the difference will be sufficient, and this effect may
be produced or enhanced by adding a small resistance to one of the contacts. In
this case also a back contact is arranged to break the tertiary circuit at each
signal.
a
In this manner whenever the key is depressed an enormous number of intense
impulses of alternately opposite sign is sent into the line, which do not constitute
current" capable of affecting ordinary telegraph instruments but which produce
the required effect in the receiver placed in the tertiary coil at the receiving
station. When there is no tertiary the back contact of the key is made to cut out
the receiver whenever the front contact is depressed.
The receiver consists of an electro magnet acting upon a speaker composed of a
strip of iron connected with a sounding board or boards. The strip may con-
veniently be constructed like the reed of a barmonium tuned to the note required.
When the impulses arriving are insufficient to actuate the speaker to the extent
required I reinforce it by placing the speaker in a steady current of air produced
by any well known method nearly but not quite sufficient to set it in action. The
current of air may in some cases be advantageously produced by means of a small
lamp arranged as a sensitive Hame capable of producing the same note as the reed.
In this latter arrangement I obtain sight signals as well as sounds, and the sight
signal can in some cases with advantage be arranged to call attention, when a
message is about to arrive, without forming part of the signals constituting the
message.
When I wish to record the signals, I employ with, or in place of the above
described receiver, a chemically prepared tape passing between two points in the
receiving circuit so that the arriving currents shall pass through the tape, decompose
the chemical, and leave a mark.
The adjustment of the various organs to a given note is only of great importance
when I desire to send more than one electrophonic message at the same time on
the same wire and I further assist this object by constructing, my electrophonic
secondary and tertiary of finer wire and wire of higher resistance and increase the
intensity (not necessarily the quantity) of my battery in proportion as I wish to
produce a higher note.
When I wish one transmitter to actuate several different receivers separately,
I arrange the requisite number of contact screws to act in different positions on
the break and so make the requisite difference in the number of impulses. The
key is arranged to complete the circuit through either of these screws, by means of
a switch.
But when I wish to add a single electrophonic service to a wire the adjustments
are not necessary (though they are advantageous)-I can use as a transmitter any
ordinary induction coil with a break, provided it be attached to an electrophone,
and as a receiver any electro magnet associated with a simple speaker as above
described. The speaker of the receiver may be made to act as a relay to make and
break a local circuit.
These instruments are available for calls in connection with telephones, in place
of the ordinary call bell, and also in place of call bells of all descriptions.
In some cases the speaker can be actuated by the core of the induction coil of
the transmitter which then becomes both transmitter and receiver. The effect may
be increased by adding an iron jacket to the outside of the coil which then
becomes an electro-maguet of opposite sign to the core. In this case the speaker

page_text: must be held at a point or points intermediate between the core and jacket and
its ends or edges left free.
.
All the arrangements described in my electrophone patent No 10990 in the year
1884 for carrying forward and connecting together conductors so as to tranmsit
telephonic messages without carrying forward the ordinary telegraphs are available
for electrophonic telegraphs, as for telephonic messages.
CARPMAEL & Co.,
Agents for the Applicant.
I, CHARLES LANGDON-DAVIES of 110 Cannon Street in the City of London
Electrician do hereby declare the nature of this invention and in what manner the
same is to be performed to be particularly described and ascertained in and by the
following statement :-
According to this invention telegraphic signals are transmitted by means of
phonoporic induction coils furnished with vibrators and in conjunction with
electrophones or as I prefer to call them phonopores in such a manner as to
permit of one or more phonoporic transmissions at the same time on one wire, and
so that these transmissions may if required take place simultaneously with the
ordinary telegraphs.
I usually construct the transmitter coil in three parts-First-the primary
which may be made of single or multiple wire and advantageously of the latter.
It includes the battery, the break or breaks hereafter described and the key.
2nd The secondary which is not a circuit but a phonopore composed of my patent
multiple wires of two strands one end of each strand being carried to the line or
line and earth on either side of a sufficient resistance, the other end being
insulated. 3rd A tertiary consisting of a circuit of insulated wire including the
receiver and key.
This transmitter is illustrated by the Drawings annexed.
Figure 1. illustrates the arrangements in the primary circuit.
a a is a bobbin on which the wires are wound about a core consisting of a
bundle of soft iron wires b b. The primary coil in this example consists of two
wires each separately silk covered and then laid together and again covered with
silk or this second covering may be omitted. The ends of the wires of the primary
emerge from the bobbin at 1 and at 2. Opposite the ends of the core b b are
spring vibrators or free reeds c and c¹ which when in motion yield different
musical notes or vibrate at different rates. When the vibrators are not attracted
by the core they rest against stop screws d d and through these they complete

page_text: "
battery circuits unless the key be open. e is the battery. f and f¹ are transmitting
keys. When the, keyf is depressed the battery circuit is completed from one end
of the primary wires 1, to the stop screw d and the vibrator c to one pole of the
battery: thence; through the battery to the end of the wires 2 at the other end of
the bobbin. By the current circulating in this circuit the core is magnetised, it
attracts the vibrator c away from its stop d'and this opens the circuit, the vibrator
then again falls back and this motion is repeated at the proper rate of vibration of
the note to which has been tuned. In this way the circuit is opened and closed
repeatedly very rapidly and rhythimcally..
In cases when very high notes are used and the parts very carefully adjusted 1
the circuit would never be actually broken: a difference of pressure at the point of
contact on the vibrator is sufficient to produce the necessary impulse in the
phonoporic secondary.
A similar result is brought about if the other key f¹ is put down but with a
difference in the intervals of make and break consequent on the different dimensions
purposely given to the vibrator c¹..
The dimensions to be given to the parts may be for an instrument to be used on
an aerial circuit of medium length as follows:-The core 3 inches in length and
of an inch in diameter. The primary to consist of two N° 24 copper wires
braided together or wound side by side, so as to make 3 layers of wire or when
very exact results are required the primary may consist of four separate layers of
insulated wire the four ends of each layer to be joined together at 1 and 2 Figure 1.
This gives the requisite number of turns in the primary without winding any part
of it back on another part. An additional wire of very high resistance say No 38
German silver wire may also be wound with the copper wires or one or more of
them, and the No 1 ends of the. German silver, connected to the No 2 ends of the
copper wires in this way the effects of the extra current in the primary are
obviated and the current or impulse in the secondary phonopore which results from
the breaking can be regulated so as to the equal with that resulting from the
making of the primary circuit. The sparking of the contact is also obviated by
this means..
The battery to have an electro motive force of about 6 volts:
Figure 2 illustrates the arrangements in connection with the secondary coils.
a is the same bobbin as before, and bb'are the ends of the core but to avoid
confusion the other parts indicated in Figure 1 are omitted.
The secondary phonopore consists of two wires separately silk covered and then
laid together and recovered or two wires may be carefully wound together without
recovering. These wires may be N° 38 B. W. G and about 400 yards long.
The strand is wound on the bobbin, over the primary and its ends are brought
out from the bobbin at the points marked 3. 41 and 4. 3 I. One end 31 and one
end 4 I is left insulated, the others are connected respectively to the line wire and
to earth or, it may be to two line wires. These wires for the purposes of the
ordinary telegraphy when it is simultaneously carried on along the line will also
be connected as at g-which represents any ordinary telegraphic receiving instru-
ment the resistance of which should not be less than 250 ohms and may increase
to infinity.
These wires of the secondary phonopore, thus constitute free ends to the
line wires by which they are coupled but without through circuit and by
which they are in like manner connected with the transmitting and receiving
arrangements.
The harmonic telegraph receiver I frequently place in a circuit consisting of a
tertiary wire wound upon the bobbin a over the other winding.
It may be two layers of a silk covered copper N° 30 B. W. G.
This wire emerges from the bobbin at the points 5. 5. and its two ends are
coupled with the terminals of the harmonic receiver.
In some cases the receiver is placed in the line wire and the tertiary circuit
dispensed with.

page_text: The break or free reed in the transmitter is adjusted to produce the number of
vibrations necessary to make the note or tone required in the receiver, or mado
adjustable to various notes by means of springs or slides or contact screws in various
positions. It is actuated in the ordinary way by the soft iron core and sometimes
When it is not con-
as indicated above I place a break at each end of the core.
venient to produce the required nuniber of vibrations in this way I use a break
actuated by mechanical means.
The transmitting key K may be an ordinary Morse key, the two front contacts
of which make and break the primary while the two back contacts simultaneously
break and make the tertiary, so that the receiver R at the transmitting station is
cut out and its sound inaudible when a signal is leaving By this means confusion
between leaving and arriving signals is avoided. This result can often be obtained
by making the transmitting and receiving notes at the same station different, so
that the respective transinitters shall not actuate their own receivers but only the
distant receivers.
In these cases the dots and dashes are represented by short and long' contacts
of the key producing short or long sounds at the receiving station, the sending
operator' can ascertain that his signals are leaving either by listening to the soft
sound of the transmitting break, or looking at the spark at the contact screw.
•
Or the key may be constructed to work right and left like the drop lever key of
an ordinary needle instrument and the transmitter as above described made to
produce two sounds (representing right and left signals) by arranging breaks at
each end of the core of different adjustment, one actuated only by the right the
other only by the left hand movement of the key, the Morse keys f and f1 in'
Figure 1 being omitted and the drop lever K2 substituted as shown in Figure 3.
When there is only one break a sufficient distance may often be made by a
difference in the shape of the contacts of the key. If for instance the right hand
contact be made a quarter of an inch in diameter and the left hand contact a knife
edge the différence will be sufficient, and this effect may be produced or enhanced
by adding a small resistance to one of the contacts. In this case also a back
contact is arranged to break the tertiary circuit or cut out the receiver at each
signal.
In this manner whenever the key is depressed many intense impulses of alter-
nately opposite sign are sent at a definite rate into the line, which signals do
not constitute a "current" capable of affecting ordinary telegraph instruments but
which produce the required effect in the receiver at the receiving station. When
there is no tertiary the back contact of the key is made to cut out the' receiver
whenever the front contact is depressed.
The receiver may consist of an electro magnet acting upon a speaker composed
of a strip of iron connected with a sounding board and this is sufficient for many
purposes, such as simple signals and telephonic calls. In instruments for more
important purposes, the strip may conveniently be constructed like the reed of a
harmonium similar to the free reed vibrator of the transmitter tuned to the note to
which it is required to respond and caused in responding to actuate a relay in a
local circuit as hereafter described. When the impulses arriving are insufficient to
actuate the speaker to the extent required I reinforce, it by placing the speaker in
a steady current of air produced by any well known method nearly but not
quite sufficient to set it in action. The current of air may in some cases be
advantageously produced by means of a small lamp arranged as a sensitive flame
capable of producing the same note as the reed.
Figure 4 represents schematically a transmitter and receiver with relay and a
bell, telegraph, sounder printer or any other apparatus working in a local circuit at
the receiving station.
a. a is the transmitter coil indicating the wires of which it is composed.
Upon the soft iron core b. b. is wound a single layer of insulated copper wire A,
N° 24 B. W. G. the ends being brought out at 1 and 2. Over this is another
layer B, then a third layer C and then a fourth layer D, the ends of each being

page_text: brought out in the same way and all joined together at 1 and 2 i.e. the two ends of
the coil. S. S. S. is a fine wire of high resistance wound in company with one
or more of the copper wires but its No 1 end connected by S2 to the No 2 end of
the thick wire and its 2 end connected by S¹ to the No 1 end of the thick wire.
This is the primary coil, and it is connected by 2 x to the front contacts of a
manipulating key K, and thence to the battery. The battery is connected at its
opposite pole by 1a 1a to the contact screw of the free reed vibrator C and
through the vibrator to the primary coil at its other end. At each pressure of K
the vibrator C is set in motion at its proper rate which motion is continued until
key K is released.
P is the secondary phonopore, consisting of two wires of N° 38 B. W. G. wound
together side by side (and they may be covered together). The wires are only
drawn separately for clearness, they should be wound together simultaneously.
One end of one wire at 4 is connected through the receiver to the line, the other
end of the same wire is insulated at 4 I. That end of the other wire which is
beside 4 I is then connected at 3 (either through another receiver not shown here,
or directly) to the line or earth wire, and the other end of the same wire is insulated
at 3 I. It is important to observe that the two wires being wound together, the
two ends with which the coil is commenced, must not be connected together or with
the line separately, and the same applies to the two ends, with which the coil is
finished; one of the commencing ends must go to line, and the other must be
insulated; and one of the finishing ends must be insulated and the other go to
line. The dotted line G indicates where a telegraph. or other instrument worked
in a circuit, may be placed.
The receiver in this case is not shown in a tertiary circuit of the transmitter
coil, as it may sometimes be, but it is inserted in the line by means of a loop in
the wire No 4. K2 represents the back contacts of the manipulator K, and cuts
out the receiver when signals are transmitted. In duplex working these back
contacts are omitted and the receiver is not cut out but its vibrator is adjusted so
that it shall not respond to outgoing impulses from the home receiver.
H, H is the iron core of the receiver: it may be magnetised or not: when very
rapid vibrations are required I prefer soft iron strips bound together, and kept
slightly charged with unstable magnetism by means of a coil RC at the upper end
of the core, which coil is in the relay circuit containing the battery R B. This
also assists the effect of the arriving currents in the relay circuit, thereby supporting
the action of the receiver vibrator R V, and in some cases replacing it. Around
the lower end of the core a coil of fine wire say No 40 B. W. G., and 1000 ohms,
is wound, and the ends of this coil are connected to the two leads of the loop in
the line.
Sometimes I wind two wires together and connect them as in the case of the
secondary phonopore of the receiver. Or again I wind the two wires together and
connect one of them in circuit with the line and the other in circuit with the relay.
In this case neither the vibrator or core of the receiver are necessary.
The relay circuit includes an electro magnet R. M whose coils lead through the
coil R C to a small battery R B, thence through a suitable resistance R to the free
reed vibrator RV which when at rest, touches the light spring contact S C and so
completes the relay circuit. The relay current is adjusted by the resistance R or.
other suitable means, so as to be only just strong enough to cause the electro
magnet to hold up the armature A A in the local instrument circuit. When
impulses travel in the coil R at the proper rate to which the vibrator R V is
tuned, this vibrator is agitated and even if it do not break the relay circuit, it
varies its resistance so as to release the armature A A which falling against the
contact screw B B completes the local instrument circuit through any battery
actuating any instrument. When the vibrator R V ceases to be agitated the
equilibrium of the relay circuit is restored and the armature A A is held up,
The necessary variation in the relay circuit may sometimes be produced without
the vibrator RV. The circuit being completed by the dotted line DL the impulses

page_text: in the coil R will induce others in R C.. Or they may be produced in a two wire
coil as previously described, without vibrator or core.
When the tuned vibrator R V is dispensed with, the armature A A must be
tuned for the purposes of harmonic telegraphy.
When the various organs are suitably tuned duplex and multiplex working can
take place thus. The transmitter at station A being tuned to the receiver at
station B, duplex working can take place.
The impulses generated in a secondary phonopore are scarcely affected by ordinary
electrical resistances, a large number of tuned receivers may therefore be attached
to one transmitter and these receivers may be placed in the lead to line, the lead to
earth, the tertiary circuit or all three.
As when a number of phonopores are coupled together in multiple are they do
not injuriously affect each other, inany transmitters may be so connected (in arc)
to one wire, and by these means many messages may be sent and received at the
same time on one wire.
They can also be connected in series but with some little disadvantage.
The adjustment of the various organs to a given note is only.of great importance
when I desire to send more than one phonoporic message at the same time on the
same wire and I further assist this object by constructing my secondary phonopore
and tertiary of finer wire and wire of higher resistance and increase the intensity
(not necessarily the quantity) of my battery in proportion as I wish to produce a
higher note.
But when I wish to add a single phonoporic service to a wire the adjustments
are not necessary though they are advantageous.
These instruments are available for calls in connection with telephones, in place
of the ordinary call bell and also in place of call bells of all descriptions.
Sight and sound signals obtained by the aid of sensitive flames are very suitable
for call signals. The arrangement I employ is as follows:-I provide at each station
a gas burner surrounded by an iron chimney and around the chimney and fitting
loosely upon it I have a bobbin with a wire or wires wound upon it in which
harmonic currents transmitted by the line wire circulate.
The dimensions of these parts will vary for each station upon the circuit.
I will describe the arrangement for one station:-I have a chimney of one inch in
diameter and twelve inches long and a small gas pipe passing a short way up the
chimney and terminating in an orifice 3½ of an inch in diameter. Over the orifice
and about 4 inches from the bottom of the chimney I provide a diaphragin of wire
gauze and the gas is burnt on the surface of the gauze.
The flame in a natural condition burns flat upon the gauze but when suitable
harmonic currents pass in the coils it shoots up in the chimney and burns as a tall
slim flame and so it continues until the disturbance has subsided. It is only
harmonic currents of suitable frequency which will produce this effect.-Having
arranged the chimney and burner it is easy by trial to adjust a vibrator to transinit
suitable harmonic currents. This vibrator will then be used to call the station to
which it has been adjusted-it will not affect the sensitive flames at the other
stations provided sufficient difference be made in the dimensions of the chimney
and other parts between station and station.
It is only the lower part of the chimney which I form of iron, the upper part
I make of glass so that the alteration in the flame may be readily observed.-
Sometimes I dispense with the gauze diaphragm and burn the gas in the same
position direct from the orifice by which it issues. It is then easy to adjust a
vibrator to cause the flame to produce a musical note in the tube.-I find that
the adjustment is facilitated by somewhat contracting the lower end of the
chimney.
All the arrangements described in my electrophone or phonopore Patent No 10990
in the year 1884 for carrying forward and connecting together conductors so as to
transmit telephonic messages without carrying forward the ordinary telegraph
siguals are available for the phonoporic telegraphs or for telephonic messages.

page_text: Having now particularly described and ascertained the nature of my said
invention and
and in what manner the same is to be performed I declare that what
I claim is
thrus
+ #
:
1. Telegraph apparatus consisting of a bobbin on which several wires are
wound some constituting a primary circuit including a battery a key and a vibrator
or like mechanical instrument rapidly opening and closing the circuit and others
connected by one end only with the line wires substantially as described.
2. Telegraph apparatus in which harmonic currents are transmitted interrupted
and received whilst the line wires are not connected in circuit with the transmitter
and receiver but only coupled by free ends substantially as described.
3. Telegraphic apparatus in which harmonic currents transmitted on a line
from a sending station are at a receiving station made to reduce the influence of a
local battery on a relay tongue causing it thereby to fall back to its stop and
complete the local circuit of a receiving instrument.
4-Telegraph apparatus in which harmonic currents transmitted on a line from
a sending station produce vibrations at a receiving station and influence a sensitive
flame and so gives a visible or audible signal substantially as described.
5. A telegraph instrument having a bobbin wound with primary wires in
parallel arc and with phonporic coils and having also a vibrator or like instrument
producing harmonic currents in the primary substantially as described.
6. A telegraph instrument having a bobbin wound with primary wires and with
phonoporic secondary coils and with a tertiary coil connected with a receiver
substantially as described.
7. A telegraph instrument having a bobbin wound with primary wires in
parallel are and with phonoporic secondary coils and with a wire of high resistance
wound with the primary and connected with them in circuit in the manner herein
described.
8. Telegraph apparatus substantially as described and represented in the
annexed drawings.
1
1
T
1000