Improvements relating to Electric Telegraphy.
Year: 1897

page_text: PROVISIONAL SPECIFICATION.
Improvements relating to Electric Telegraphy.
We, OLIVER JOSEPHI LODGE, of 2, Grove Park, Liverpool, in the County of
Lancaster, D.Sc., F.R.S., Professor of Physics in University College, Liverpool
aforesaid, and ALEXANDER MUIRHEAD, of Princes Street, in the City of Westminster,
D.Sc., Electrical Engineer, do hereby declare the nature of this invention to be
as follows:-
--
Our invention relates to the utilization of Hertzian waves emitted by any form
of electric radiator or oscillator-that is to say oppositely charged conductors
sparking into each other for the purpose of telegraphing to one or more distant
stations or points without the necessity of metallic or other conductors between
such places. In carrying out our invention we use as receiver a siphon recorder
or any other instrument which responds to variations or fluctuations in the
strength of an electric current and we actuate such receiver by a local battery
connected to it through a light contact, or a number of light contacts, of any kind
which normally opposes to the current a comparatively high resistance, but which
resistance falls under the influence of electric waves received from the distant
station. Such a receiver depends for its action on the fact of electri-
cal cohesion or more complete contact set up under the electrical stimulus
of Hertzian waves, (and is called a coherer") and the mode in which we utilize
these already known principles and the apparatus we have devised and assembled
for that purpose constitute the main features of our present invention.
According to our said invention we may place the coherer in direct circuit with
the recorder or other receiving instrument in such a way that its recording part
moves perceptibly whenever an arriving electric wave reduces the resistance of the
coherer. This same motion is caused in some cases to act on the cohering surfaces
in such a way as to separate them, sufficiently to interrupt, or greatly weaken, the
current and to allow the whole arrangement to revert to its original receptive
condition.
In addition to, or in substitution for, this mechanical mode of restoring sensitive-
ness to the receiver, we may also utilize the momentarily strengthened current itself
to achieve that object magnetically. To this end the coherer has associated with
it, or forming a principal part of it, a piece or pieces of iron or other magnetic
material, no matter how minute it may be, and near this piece of iron or its
equivalent is a coil of wire or other electromagnet placed either in direct circuit
with the recorder and the coherer, or in a local circuit therewith, so that whenever
the current in the receiver circuit becomes more pronounced by reason of cohesion.
setting in under the influence of an electric wave, the same enhanced current shall
at once disturb or break the cohering particles asunder again sufficiently to enfeeble
or reduce the current to its original infinitesimal value in readiness for the next
signal.
Sometimes instead of employing the rise of the current which flows through the

page_text: coherer to undo the effect of the electric wave on the surfaces of the contiguous
particles which constitute the coherer we may make use of an entirely separate and
independent piece of mechanism constructed on the lines of the "
"
curb commu-
tator described in the Specification of Letters Patent No. 11069 of 1894 granted to
one of us. A cylindrically shaped skew-cam similar to that described in the
Specification; of the said Letters Patent is revolved either by means of an electro-
motor or clockwork or other suitable means and on its surface rides an arm which
in its motion to and fro strikes the exterior of the coherer or some part of the case
containing it. The position of the arm on the surface of the cam determined the
moment and frequency or otherwise governs the character of the blow given to the
coherer for every revolution of the cam, and by means of a tangent screw adjust-
ment this position can, without stopping the mechanism, be varied until the best
effect is obtained. By adopting this means of re-setting the coherer, the arrange-
ment of our receiver becomes much simpler in construction and more certain in
action.
12. +
7
Or according to another method of resetting the receiving apparatus we may
employ a galvanometer as a receiver the needle of which dips or passes into the
contiguous particles which constitute the cohering surfaces and which are dis-
turbed whenever such needle oscillates. Again instead of a needle, the coil of a
siphon recorder may be used in the same way and may be preferable because it
is not disturbed by stray magnetism.
According to our invention the coherer may be one with a mercury contact and
a spiral surrounded by a helix and either made of, or containing, iron so as to be
disturbed whenever a stronger current passes round the helix. We also propose
to use a spring or brush making light contact with a revolving drum or disc so
arranged that when the waves arrive there shall be instantaneous cohesion to be
broken again at once-the flexibility being just sufficient to permit temporary
adhesion.
Sometimes in a local circuit independent of that actuated by the waves, we
employ an electromagnet to whose armature the coherer is attached, the circuit
of the clectromagnet with local battery being closed intermittently by means of
a cam make-and-break arrangement similar to that hereinbefore described. This
alternate make-and-break we find can proceed automatically with very great
rapidity and by a succession of such signals we obtain the Morse or other alphabet
sufficiently well recorded on a strip of paper.
The cohering surfaces of our coherer may be of any material but we usually
make them of metal, by preference of iron, nickel or brass, and they may be
immersed in any medium, but we prefer them to be in vacuo in order that they
may not chemically deteriorate. Any number of contacts may be used instead
of one, and the same may be arranged either in series, or in parallel, or both.
When the metal is in the state of filings or powder, we sometimes arrange a
number of tubes containing such filings or powder in parallel to give greater range
of action.
Instead of a piece of iron actuated by a coil as the restorer to sensitiveness, we
sometimes use a flexible or suspended wire immersed in a steady, strong, magnetic
field, so that whenever the enhanced current passes along the flexible wire or
brush or filament there shall be a slight or barely perceptible motion across the
lines of force breaking the cohesion momentarily and restoring instantly
the previous condition of light contact. Or a rod immersed in the filings of the
coherer may be actuated by means external to the tube containing the filings to
disturb the filings on the passage of an electric wave.
As emitter of the waves we may employ spheres or ellipsoids partly or wholly
. immersed in oil or other strong dieletric with the object of charging them highly
before they spark into one another but in carrying out this invention we make
one of the spheres or other shaped conducting bodies with a depression or bath to
contain the oil and the other with a protuberance or projection to dip into. the
oil vessel and come near to the bottom of the vessel so that at this place sparks

page_text: may occur whenever the two bodies are over-charged by means of an induction
coil or other convenient known means.
The waves are competent to go through the air but in so far as they proceed
through or over the earth or along conductors imbedded in the earth like gas or
water pipes or along other wires not laid down for their special purpose they are
at liberty to do so and we may use the earth itself as one of the charged spherical
or ellipsoidal bodies to which another body shall be caused to spark.
As collector of the waves we may use any conductor or network of conductors
whether put up for the purpose or not. All that is necessary for the purpose of
this invention is that the said conductor shall be connected with the coherer in
case it by itself is unable sufficiently to feel the effect of the electric waves arriving
from a distant station.
Whenever the emitter is so planned as to emit waves of a definite period, the
collector shall be tuned to respond to these and in that case the system will be a
system of syntonised telegraphy.
In connection with the primary of the induction coil of the emitter, we may
employ an automatic telegraph transmitter to close the battery circuit according
to the Morse code in the usual way and in order to obviate the necessity of having
sparking at more than one place, we may construct the make-and-break commu-
tator of the induction coil in the following mauner:-The vibrating hammer is
kept in vibration at the proper rate by means of an electromotor independently of
the induction coil and the battery stop against which the hammer strikes is attached
to the armature of a local transmitter which is actuated by the automatic trans-
mitter. On the passage of every hole in the perforated slip of the automatic
transmitter the armature of this local transmitter is attracted to bring the battery
stop of the primary circuit of the induction coil within range of the vibrating
hammer thus exciting sparks in the emitter at every signal.
When the distance between the emitter and the coherer is too great for the
waves to travel from the one to the other, one or more relay stations may be
employed. At a relay station the waves operating on a coherer close a circuit
and bring an induction coil into operation which being connected with a local
emitter starts a fresh series of waves corresponding with those which were received
at the relay station.
Improvements relating to Electric Telegraphy.
We, OLIVER JOSEPII LODGE, of 2, Grove Park, Liverpool, in the County of
Lancaster, D.Sc., F.R.S., Professor of Physics in University College, Liverpool
aforesaid, and ALEXANDER MUIRHEAD, of Princes Street, in the City of Westminster,
1.Sc., Electrical Engineer, do hereby declare the nature of this invention and in
what manner the same is to be performed, to be particularly described and ascer-
tained in and by the following statement:.
Our invention relates to the utilization of Hertzian waves emitted by any form
of electric radiator or oscillator-that is to say oppositely charged conductors
sparking into each other-for the purpose of telegraphing to one or more distant:
stations or points without the necessity of metallic or other conductors between
such places.

page_text: In carrying out our invention and referring first to the diagram Figure 1 we
use as receiver a siphon recorder or any other instrument which responds to
variations or fluctuations in the strength of an electric current and we actuate
such receiver by a battery b connected to it through a light contact, or a number
of light contacts, of any kind which normally opposes to the current a compara-
tively high resistance, but which resistance falls under the influence of electric
waves received from the distant station. Such receiver depends for its action on
the fact of electrical cohesion or more complete contact set up under the electrical
stimulus of Hertzian waves, (and is called a coherer") and the mode in which
we utilize these already known principles and the apparatus we have devised and
assembled for that purpose constitute the main features of our present invention.
In the diagram e represents one form of coherer to be hereinafter described; dis
the siphon recorder coil; e is the usual siphon dipping at one end into an ink
receptacle and at the other end resting upon a strip of paper g to which motion
is imparted in the well understood way. Preferably the siphon plays between a
pair of adjustable limiting stops (not shown in the diagram). The electrical
circuit can be readily traced from the diagram, h representing a resistance in the
circuit.
According to our said invention we may place the coherer c in direct circuit
with the recorder or other receiving instrument in such a way that the recording
part of the latter moves perceptibly whenever an arriving electric wave reduces
the resistance of the coherer. This same motion of the recording part of the
receiving instrument is caused in some cases to act on the cohering surfaces in
such a way as to separate them sufficiently to interrupt, or greatly weaken, the
current and to allow the whole arrangement to revert to its original receptive
condition.
The better to enable this to be done we employ a coherer made on the principle
introduced by one of us and known as a "single-point coherer." Such a form of
coherer is indicated diagrammatically in Figures 1, 1, 5, 6, & 8 and is preferable,
but other forms might be employed. Its manufacture for our present, purpose,
however, involves some constructional details and the apparatus is therefore fully
described with reference to Figures 2, 3 and 4 where it is shown in plan, elevation
and part side view respectively. i is a base or slab of ebonite or other suitable
material on which are fixed three brackets j, j', j². Rigidly clamped to the
bracket by the binding screw is a strip of spring steel, phosphor-bronze or
the like. This strip extends beyond the bracket and such bracket j forms
a bearing for an adjustment screw which latter bears on the said strip k. The
bracket carries a somewhat similar adjustment screw m but at the extremity
thereof is arranged a needle-point n which is brought into slight contact with the
said strip k. It is found that this form of coherer is very sensitive to Hertzian
waves, and is one which can very readily be kept in the condition for receiving
wave impulses by the simple means to be described.
Accordingly in our invention, and reverting now more particularly to Figures 1
and 1, we mechanically connect the coherer with the receiving instrument and
thus cause the enhanced current which flows through the receiving circuit on
cohesion taking place between the needle point and the spring to bring about
decohesion and to restore the coherer to its initial sensitiveness. In these diagrams
this mechanical connection is represented at p and it consists of a very light silken
or other thread or fibre extending between the coherer strip, or an extension of
the same at the fixed end, and the recorder coil. In Fig. 1 the mechanical con-
nection is made by the fibre 2 through a pivoted serrated-edged quadrant piece y
whose serrations come into contact with the prolongation of the strip k.
The moment the coherer is stimulated, the recorder coil moves, and, instantly
upon that movement taking place, the coherer is restored to its initial sensitive-
ness owing to the mechanical connection p between the recorder coil and the
coherer. One advantage arising from this arrangement over all forms of coherers

page_text: in which metallic powders are used is the greater rapidity with which reception
and decohesion can take place. The fibre p may be provided with any suitable
length-adjusting appliances.
In addition to, or in substitution for, this mechanical mode of restoring sensi-
tiveness to the receiver, we may also utilize the momentarily strengthened current
itself to achieve that object magnetically. The diagram Figure 5 illustrates one
such method. The coherer here shown is of the description herein before fully
described and located in proximity to its strip is an electromagnet q which, after
the reception of an impulse by the coherer, serves to withdraw the strip from the
needle point and thus to break down the cohesion between the same.
To prevent permanent magnetism being imparted to the active parts of the
coherer the strip in this case is made preferably of phosphor-bronze and a small
piece of iron attached to it opposite to the poles of the electromagnet. The
recorder a is shown in this and subsequent figures in the conventional way and r
is a shunt across its coil.
Instead of the strip & being actuated by a coil or electro-magnet as the restorer
to sensitiveness as described with reference to Figure 5, we sometimes, as illus-
trated in Figure 6, use a flexible or suspended wire strip or filament v immersed
in a steady, strong, magnetic field, such for example as arising from a permanent
magnet N-S so that whenever the enhanced current passes along the flexible
wire, strip, or filament there shall be a slight or barely perceptible motion across
the lines of force of the said strip and, since the same is mechanically connected
to the coherer strip k as shown or as hereinbefore described with reference to
Fig. 1 or otherwise, it results in breaking the cohesion momentarily and restoring
instantly the previous condition of sensibility of the coherer. Or the well-known
granular form of coherer may be similarly operated where, as shown in Figure 7,
it is mounted upon a hinged arms which is under the influence of a spring s¹
subject to an adjustable limiting stop 2. The coherer tube has a piece of iron or
other magnetic material secured upon it, and near this piece of iron or its
equivalent is a coil of wire or other electro-magnet s placed either in direct circuit
with the recorder and the coherer, or in a local circuit therewith actuated by the
recorder coil itself, so that whenever the current in the receiver circuit becomes
more pronounced by reason of cohesion setting in under the influence of an electric
wave, the same enhanced current shall at once disturb or break the cohering particles
asunder again sufficiently to enfeeble or reduce the current to its original infinite-
simal value in readiness for the reception of the next signal.
com-
Sometimes instead of employing the rise of the current which flows through the
coherer to undo the effect of the electric wave on the surfaces of the contiguous
particles which constitute the coherer we may make use of an entirely separate
and independent piece of mechanism constructed on the lines of the "curb
mutator described in the Specification of Letters Patent No. 11069 of 1894 granted
to one of us. Figure 8 illustrates its adaptation to a single-point coherer, k repre-
senting part of the strip shown in Figures 2, 3 and 4. A cylindrically shaped
skew-cam t similar to that described in the Specification of the said Letters
l'atent is revolved by clockwork or other suitable means and on its surface rides
an arm t pivoted at which in its motion to and fro strikes the exterior of the
coherer or some part of the case containing it. In Figure 8 it is shown as striking
the coherer strip k, its play being limited, and its moment of striking adjustable,
by screws, . The position of the arm t¹ on the surface of the cam t or the
position of the cam relatively to such arm governs the character of the blow given
to the coherer for every revolution of the cam, and by means of a tangent screw
adjustment as in the said prior specification this position can, without stopping
the mechanism, be varied until the best effect is obtained. By adopting this
means of re-setting the coherer the arrangement of our receiver becomes much
simpler in construction and more certain in action.
Sometimes in a local circuit independent of that actuated by the waves, we
employ, as illustrated in Figure 9, an electromagnet u to whose armature is

page_text: attached a rocking beam u to which in turn the coherer is attached. The move-
ment of the beam is limited by stops u and u³. The circuit of the electromagnet
with local battery u is closed intermittently by means of a cam make-and-break
arrangement u similar to that herein before described, with reference to Figure 8.
Or the circuit of this electromagnet with local battery may be broken and made
by means of a contact arm attached to the recorder itself.
The cohering surfaces of our coherer may be of any material but we usually
make them of metal, by preference of iron, nickel, or brass, and they may be
immersed in any medium but we prefer them to be in vacuo in order that they
may not chemically deteriorate. Any number of contacts may be used instead of
one, and the same may be arranged either in series, or in parallel, or both. When
the metal is in the state of filings or powder, we sometimes arrange a number of
tubes containing such filings or powder in parallel to give greater range of action.
As emitter of the waves we may employ spheres or ellipsoids and they may be
partly or wholly immersed in oil or other strong dielective with the object of
charging them highly before they spark into one another but we do not claim
anything herein in regard to them.
As collector of the waves we may use any conductor or network of conductors
whether put up for the purpose or not. All that is necessary for the purpose of
this invention is that the said conductor shall be connected with the coherer in
case it, by itself, is unable sufficiently to feel the effect of the electric wave arriving
from a distant station.
Whenever the emitter is so planned as to emit waves of a definite period, the
collector will be tuned to respond to these, and in that case the system will be a
system of syntonised telegraphy.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed we declare that what we
claim is:-
1. In the receiving circuit of a system of Hertzian wave telegraphy, a siphon
recorder or other receiving instrument, a coherer in direct circuit with such
receiving instrument, and means whereby the enhanced current itself, which flows
though the receiving circuit after the receipt of an impulse by the coherer, brings
about decohesion and restores the coherer to its initial sensitiveness substantially
as set forth.
2. The combination, in the receiving circuit of a system of Hertzian wave
telegraphy, of a telegraphic receiving instrument, a coherer in direct circuit with
such receiving instrument, and means mechanically connecting the coherer with the
index or moving part of the receiving instrument, substantially as and for the
purposes set forth."
3. The combination, in the receiving circuit of a system of Hertzian wave
telegraphy, of a telegraphic receiving instrument, a coherer in direct circuit with
such receiving instrument, and means mechanically connecting the coherer with
a moving part of the receiving circuit substantially as and for the purposes set
forth.
4. The combination, in the receiving circuit of a system of Hertzian wave
telegraphy, of a telegraphic receiving instrument, a coherer, and means for
decohering, such means being capable of being varied as to moment, frequency and
strength of action.
5. In the receiving circuit of a system of Hertzian wave telegraphy, the com-
bination, with a coherer, of means for decohering comprising a pivoted arm.
operated by a cylindrical skew-cam, the arm and cam being adjustable relatively
to one another, the said arm serving to strike the coherer or its adjuncts in the
manner substantially as set forth.
6. The combination, with the receiving circuit of a system of Hertzian wave
telegraphy, of a local circuit containing an electro-magnet, an associated battery,
and a make-and-break comprising a pivoted arm operated by a cylindrical skew-

page_text: cam the arm and cam being adjustable relatively to one another substantially as
set forth.
Dated this 9th day of Mar 1898
A. F. SPOONER,
323, High Holborn, London, Agent for the Applicants.