Year: 1887

page_text: Date of Application, 27th Sept., 1887
Specification Accepted, 4th May, 1888
I, FRANCOIS VAN RYSSELBERGHE, of Brussels, in the Kingdom of Belgium,
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 :-
My invention consists of methods and combinations by means of which the greatest
possible number of messages are sent simultaneously on the same wire or circuit. To
attain this object I combine a system of harmonic-multiplex with the other ordinary
telegraph instruments, such as the Morse, Hughes, and others; and arrange them so
as to work simultaneously the same wire or circuit.
I will first describe my harmonic telegraph in itself: then show how it can be put
into practice on a wire or circuit already worked by other usual telegraphs: so that
the whole of the combination should give the maximum of its working capacity and
practical facilities.
So far as harmonic telegraphs are concerned, I am aware that many efforts have
been already made in that direction, with more or less success. Perhaps the most
prominent phonic system heretofore tried was one in which a series of tuned reeds was
used to produce the vibrations or variations of potential on the line, and a similar
form, of similarly tuned reeds, was used as receivers. This has met with a certain
amount of success in that a limited number of messages have been successfully trans-
mitted over a line of limited length by the use of a very large source of electric
energy.
I have made an extended research, both scientific and practical, upon this subject,
to find out not only the cause of the prior failures in this class of telegraphy, but also
to find methods and means whereby the known as well as the unknown difficulties may
be overcome in a practical manner; and I have produced a system of multiplex phonic
telegraphy which has proved to be a practical and commercial success, in that a very
large number of separate messages may be simultaneously transmitted in the same,
or in opposite directions, over a single line and to a great distance, by the use of a
very small source of electric energy. I will now proceed to describe the principles
of my present invention, and illustrate the same by one form of phonic telegraphi in
which it has been successfully embodied.
It is well known that in this class of telegraphs the transmitters are suitably con-

page_text: structed and arranged to throw or superpose upon the main line independent series of
impulses or variations of potential, varying in number or rate for each transmitter,
and the receivers are intended to be of such construction and to be so arranged that
each will respond only to the desired signals sent by the transmitter to which the
particular receiver is intended to respond, and to be unaffected by all the other signals
transmitted by other transmitters. The object is also to send and receive as many
series of signals in this manner, over a single line wire in the same or opposite
directions, as possible; and with a small expenditure of battery power.
One of the first essential principles required for a successful phono multiplex system
of telegraphy is that each transmitting device shall create or produce in the line circuit
simplex electrical tones which shall correspond exactly with the fundamental tone of
the receiving device to be used in connection with the transmitter; or, in other words,
it is certainly desirable, if not essential, that the simplex electrical tones produced by
the transmitter should not be accompanied by overtones or harmonics of the same or
other secondary tones. In the devices heretofore used for transmitting where the
contact making and breaking or circuit controlling devices have been in the form of
reeds, tuning forks, a spring bearing upon a revolving cog wheel, and the like this
has not been the case, as the shock of the reed, or fork, or spring against the contact
making devices creates overtones as well as tones arising from the shaking of the
contact piece on account of the shock. Further it is desirable to avoid the prejudicial
effects due to sparks from the so called extra current at the breaking of the contact ;
which not only is destructive to the machine, but also interferes with the simplex
tones being produced by the transmitter.
Next, it is desirable that the impulses or variations of potential should always be
produced in the various transmitters at a rate bearing a certain fixed relation the
rates of all the others, regardless of the speed of the transmitting device, as by this
means I avoid the necessity of separately adjusting each transmitter to produce its
normal rate, and am not therefore liable to disturb the balance between it and the
others and their respective receiver.
In order to accomplish these results I have found one of the best means is a cylinder
or disc of some suitable material, nickel and silver being preferred as they are hard,
non-oxidizing and fusible only at high temperatures. This cylinder is properly
mounted and rotated, in a manner hereafter described, at a very regular rate of speed;
say ten revolutions per second, for example. Now suppose, for instance, I want three
transmitters sending respectively 180, 200, and 220 electric impulses per second to
line; I make three series of insulated spaces or openings in a circle around the cylinder
or dise; the insulating spaces or holes being equal in length to the metallic conducting
spaces or intervals between them, and I place in one row, say the upper series
18 insulating, spaces or holes; in the next 20 holes; and in the third 22 holes. There
are various ways in which these insulating spaces or openings may be formed; many
of which are obvious, though it is one of the essentials that the holes be filled with
some material in order to prevent the harmonics and other sounds caused by the brush
or contact piece striking the edges, and I have found it very desirable to fill the
holes with the same material as the cylinder itself; and I therefore fix in the
holes plates or blocks of nickel or silver by means of an insulating cement.
I thus provide a cylinder or disc with a substantially uniform surface over which
the brushes or contact pieces can travel without jar or friction, and in which the wear
of the surface is equal in all parts; and, by making each insulating space or block
separate from the body of the cylinder, if by chance the insulation between any one
block and the rest of the cylinder becomes destroyed or defective, that space only will
be affected by it and not the rest of the spaces of the same series or of other series;
and it will not interfere with the proper transmission of the impulses. I arrange
metallic brushes so that each will pass over its proper series of filled metallic insulated
spaces, and conducting spaces between the latter; so as to alternately open and close
the circuit of a battery, of which one pole is connected to the brush and the other with
the mass of the revolving cylinder; and is thus arranged to send the impulses to line
in a manner hereafter described.

page_text: By this arrangement I am enabled to throw upon the line different series series of
pure simplex tones unaccompanied with overtones or other disturbances, and as all
the circuit making and breaking devices bear a fixed relation to each other and rotate
at the same speed, the rate or number of impulses sent by each of the transmitters
will bear the same proportional relations to each other, no matter what the rate of
rotation of the cylinder may be; and all adjustment of the transmitters to produce
such proportionate rates is avoided. Furthermore, the brushes constantly bear upon a
metal surface, the space occupied by the insulating material being very small between
the conducting cylinder and the insulated metal spaces, the wear of the edges of the
contacts is reduced to a minimum, and the sparks are small and may be further provided
for by a spark condenser, or spark avoiding shunt as is common.
This
Perhaps the most essential principle of all is that the rotating cylinder or disc, or
other circuit controller shall have an absolutely perfect isochronous motion: not only
so that the transmitters at any given station may always send the impulses to line at a
given rate of speed, but so that all the transmitting devices at all the stations in the
system may be arranged to be rotated in absolute synchronism and all the receivers
which aro adapted to respond to any given rate may be able to respond to any one
of the transmitters at any and all stations transmitting tones having that rate.
principlo has heretofore been recognised by persons engaged in experimenting upon
phonic systems and many attempts have been made to overcome the difficulty; and most
of theso attempts have been in the way of correcting the evil, instead of preventing it.
That is to say, instead of producing absolutely synchronous movements, they have
produced only partially synchronous movements in applying, not "regulators,"
absolutely, isochronic, maintaining the speed absolutely uniform, but in utilizing
mere moderators; which, true enough, keep the speed within certain limits; but
which cannot hinder the speed from varying to a certain extent, within these limits.
It is hardly necessary to state that the nearer we succeed in producing an isochronic
motion, the more effective will be the succeeding electrical impulses in acting upon
the receiver instrument: especially if it be a tuning fork to put it into vibration by
their accumulated energy; as each impulse must act at the proper moment, and no
impulse will in any way counteract the notion imparted by the previous ones.
:
Further it is apparent that under these conditions, the larger will be the number of
messages that can be sent simultaneously over the same wire without interference ; as
the margin of variation in the vibration of the forks is much smaller. I have found
it advisable to mount the cylinder upon a nicely balanced vertical shaft running in
polished or jeweled bearings and to drive the shaft by some constant power, preferably
à dynamo electric motor operated by a battery, or other source of electric energy, of
very low internal resistance, as a secondary cell. The circuit of this battery and
motor includes a variable resistance, the amount of which is preferably controlled by a
proper governor (as will be described hereafter), in such a way that the resistance is
controlled in a gradual and uninterrupted manner without ever making or breaking
contact, either in the resistance or at the commutator of the motor; for any such
making and breaking would cause in the driving current sudden or abrupt variations,
and therefore variations in the speed of the revolving cylinder; which variations,
though small, will nevertheless, be prejudicial.
In order to control this resistance so as to obtain absolute isochronous movement in
the motor, I have found it desirable to have the governor or moving mass controlling
the resistance, quite independent of internal mechanical resistance, such as friction and
the like; and it should entirely be at liberty to move under the sole respective:
influences of gravity and centrifugal force; and for a given angular speed, the cou-
ditions of its equilibrium must be exactly the same at every point of its path, or in
every part of the resistance. As far as I have observed, these requirements cannot
be dispensed with, and an absolutely correct governor be produced. In order to
realize such a governor we may imagine a metallic ball or balls resting upon two
parallel and revolving curved rails of low conductive and non-oxydizable material;
preferably driven by the same motor as the transmitting cylinder: the circuit of the
dynamo motor and the driving battery including that length of the rails located

page_text: momous.
If instead of rolling on the curve at the whole distance of its radius, as shown in
Fig. 12 the governing sphere was rolling between two parallel rails, (see Fig. 13),
separated one from the other by a distance d, the required isochronic rails would
be the same as above, only replacing r by the value of the distance C M. Instead of
driving the cylinder or disc by an electric motor, the circuit of which includes the
variable rosistance of the isochronic rails located between the governing balls; I could
drive the instrument by an electro or another motor in the usual way; the motor
itself being independent from the isochronic governor, but the latter controlling by
its variable electric resistance the amount of variable friction of a brake worked by an
electro magnet, the intensity of the current flowing through the latter being controlled
by the electric resistance of the isochronic governor.
Another important principle relating to phono multiplex telegraphy is found in
the arrangement of the battery or other source of energy and circuits in connection
with the main line circuit controllers, local circuits, etcetera. When, for instance,
two transmitters are each sending simultaneously an electric impulse to line, the
strength of the current, or the amount of the electrical potential variation has to
have twice the value as when one transmitter only is operating to send the impulse.
I have found that it is much more desirable to send induced or high tension currents
to the main line, than battery currents, as in the manner used by Varley in bis
harmonic system; as they can be made to retain their characteristics a greater time
and over greater lengths of wire without interference. But in using several trans-
mitters, if we had to put an induction coil for each transmitter in the line, the current
from one of the transmitters would have to traverse the secondary circuits of all the
inductoriums, both at the transmitting and receiving end of the line; and as an
induction coil on account of its self or magnetic induction, is a serious obstacle to the
rapid undulatory currents: the latter being graduated thereby, they would greatly
reduce the strength of the currents on the line, and consequently the distance to
which a great number of simultaneous messages could be sent through one wire.
Therefore at each end of the line, I use but one induction coil only, and I preferably
use but one battery for each transmitter.

page_text: Another essential feature is to use a generator of very low internal resistance, as
one thousandth of an ohm; the primary circuit of the induction coil should also be of low
resistance, as one hundredth of an ohin; but to get the best results I put a somewhat
noticeable resistance, as one half of an ohm or so, in each derived branch of the
transmitter circuit. These derived branches should include the isochronic revolving
cylinder, the brush bearing upon the cylinder, the key and the resistance above
specified, and all the derived branches close the circuit through the battery and the
common primary of the induction coil.
With a system constructed to embody the above principles, the question arises how
many simultaneous harmonic messages may be transmitted in one or both directions
over a single line wire without interference; and I find there are certain principles
governing this which I will now endeavour to explain.
A tuning fork, tuned for instance to a rate of 360 vibrations per second, will
respond not only to impulses of that rate but also of any rate which is about an
exact divider of the former; that is to say, that a fork, the fundamental tone of
which is 360, will also respond to 180, 90, 60, or 45 vibrations; and so on. Of course
a transmitter giving 45 impulses only, will not act as efficiently thereupon as another
transmitter giving 360 pulsations; but still the influence is large enough to create
false signals, or to break up the signals when working long distances. My experience
is that a tuning fork tuning at a number of n vibrations, is influenced to a prejudicial
amount by a transmitter giving only impulses a second. Therefore we are compelled
to confine ourselves to notes included within one octave only ; at least the tone of
one receiver of a set being for instance "do," we cannot on the same line have a
We can use re
receiver the tone of which would be "do", or "do "3.
n
"
פנג
66
or rea
But I find it best
if, for some reason, we prefer to take a higher tone than "re".
to select tones in the same octave and to chose low tones, as low electrical tones are
able to go over, and to produce better effects, on longer distances of wire, (especially
of iron wires), than high tones, on account of self induction; and as the margin for
low tuned forks is smaller than the margin for tones belonging to the medium of the
musical scale, I can send a greater number of messages over the same wire. This
of course requires a greater regularity in the motion of the revolving cylinder; but
therein, precisely, lies the advantage of my perfect isochronic governor above
described; and it is one of the reasons why I succeeded in producing a practical
system.
=
c, or a
A tuning fork, tuned at the rate of n impulses, will respond not only to the dividers
of n, but also three given tuning forks being tuned at the rate of a, b, c, vibrations,
if the electrical impulses a and b be sent at the same time and that a b
divider of c, the third fork will respond, instead of being silent, as is necessary for
the required object. So as to avoid that the fundamental tones or their combinations
should have any prejudicial effect on the fork receivers for which they are not
intended, 1 take tones of which the number of vibrations have no common dividers
and are as much as possible first numbers or primes. It is so that the ratios,:: 49:
53: 57 61: 65: 71: 77: 83: 91 are very convenient, and even form the limit of
the possible successful combinations.
In order to produce suitable receivers for the simplex tones produced by my
isochronic transmitters, I have found that the principle involved is that of the
pendulum to which a great number of successive impulses imparted thereto, (even if
each of the impulses is very weak), will after a while produce an ample vibrating
motion, through the accumulation of energy, if each impulse is given at the proper
time; and if its effect is not wasted outside the pendulum, reed, or tuning fork, (for
the tuning fork is but a kind of pendulum), will be put into easily perceptible motion
by the series of impulses: each of which would be incapable in itself of displacing the
mass or bending it to any perceptible amount.
I have found that tuning forks are much more suitable than vibrating reeds; for
when a reed is used a great amount of energy is wasted in putting its support into
'

page_text: motion; and such wasting does not occur, or only in a much smaller degree, when
properly balanced tuning forks are used.
In using such tuning forks as receivers, I have found another requirement is
essential. For instance, suppose we want to produce by sound, or otherwise, the
following Morse signal,
In order to produce the dot or the dash, the tuning
fork must be put into perceptible motion and this motion has to be stopped instantly
as soon as each signal is completed, in order to have "clear cut" signals. These are
apparently contradictory requirements, for when once a tuning fork is put into
vibration, its property or tendency is to go on vibrating for a considerable while after
the imparting pulsating efforts have ceased. I have found, however, that this
difficulty can be successfully overcome by making use of permanently magnetized
tuning forks, or equivalents thereof; in other words by creating between the fork,
or the branches of the fork, and the coil or coils acting thereupon, a permanent
magnetic field; the variations of which field through the variations of potential
created in the line wire by the proper transmitter, will put the fork into vibration as
long as such variations in the field are created; but will stop, almost instantly, the
vibrations, when the periodically varying current ceases. Not only will the tuning
fork stop, but I have found it will respond much better to the currents if there is a
pre-existing magnetic field between it and the coils, then when there is no permanent
magnetism there; and this is an aid in reaching larger distances and having more
simultaneous messages.
The receiver must also he so conceived as to prevent the prejudicial effects of
induction. Induction from one line or circuit to another, exists as well in ordinary
telegraph as in telephone lines. But while in telephone the induction is exceedingly
prejudicial and compels us to recur to the use of complete metallic circuits, in
ordinary telegraph lines, on the contrary, the induction, even between simple wires
does not disturb. The reason of this is that the telephone responds to all currents,
as weak as they may be, while the armature of a telegraph instrument, will only
move for currents of a determined strength any current inferior to this minimum
being non-effective.
To reach this last object in harmonic telegraphs, and so to place each receiver in
such conditions as to receive only the currents intended for that receiver, and to
shelter it from the other currents that are generally weaker; I fix a small mass or
hammer, held by a light spring, to the end of one of the legs of the tuning fork, and
I place in front of this hammer a gong or other resonant, body; that I can, by means
of a screw, adjust so that when at rest the small hammer will be pressed against the
resonant body. When the amplitude of any vibration of the fork is less than that
required to bend the spring, the effect on the body will pass unheard; but an
amplitude capable of producing the separation of the small mass or hammer from the
resonant body will produce signals perceptible to the ear: the hammer striking the
resonant body at each vibration.
In establishing a local circuit by the hammer, the resonant, a battery and a relay,
these signals can be produced in a sounder or a recorder. The system of harmonic
telegraph herein described, can be put in activity on a wire or circuit already
employed by an ordinary telegraph instrument, as Hughes or Morse, by putting the
harmonic telegraph in a derived circuit by means of a condenser. But it then
becomes indispensable to use graduated currents for the telegraph; that is to say,
currents with progressively growing emissions and progressively decreasing extinctions.
Without this, false signals will be produced in the harmonic receivers.
I have fully described my system of graduated currents in previous Letters Patent
of date 23 November 1883 and No. 5503; so that I need not describe them here. If
it is a Morse instrument that is used simultaneously with the harmonic system, there
is no other precaution to be taken than that of graduating the currents. If a Hughes,
or other instrument based on the synchronism of the two motors new improvements
are necessary, especially if, to augment the capacity of the line, we set the Hughes in
duplex or quadruplex. When such instruments are put in duplex or quadruplex,
defects of synchronism are especially objectionable as a slight error in the balance, as

page_text: well as a fault of synchronism will result in the printing of a false letter, causing all
the following letters to be equally false. The operators having no means to ascertain
immediately whether the false letters are due to one cause or the other, are delayed;
and frequently put the sets quite out of order when trying to correct by synchronism
a fault, which is really due to a slight error in the balance, or vice versa.
Having now fully described the principles which govern my improved system of
multiplex telegraphy, I will illustrate one form of its practical embodiment by
referring to the accompanying drawings forming part of the specification; in which,
Fig. 1 is a diagramatic view of a transmitting apparatus. Figs. 2, 3, 4, 5, 6, 7, and 8
are views illustrating various embodiments of receiving devices; and in Figs. 9, 10,
and 11 I have shown diagrams of various arrangements of the receivers ; and
diagrams Figs. 12 and 13 illustrate the manner of constructing the parabolic
governor.
Upon suitable supports is mounted a dynamo electric motor, 1, 2; the armaturo
shaft, 3, of which is extended upward and carries the metal cylinder 4 which is
provided with the desired number of series of openings 5, filled with metallic pieces 6,
separated from the body of the cylinder by insulating material 7; and the other end
of the shaft 3 is provided with suitable connections, shown as a worm screw 8, and
pinion 9 connected by shaft 10 and bevel cog wheels 11 to the rotating shaft 12, of
the parabolic governor.
This governor is provided with rails: 13, 14, of low conducting material connected by
means of the brushes 15 with the circuit of the generator 16, which includes the field 1
and armature 2 of the dynamo motor; and the balls 17 are adapted to move upon
the rails and to include more or less of them in circuit according to the variations in
the mechanical resistance to the rotation of the motor. This construction and
arrangement of the rails are such as were heretofore indicated; in that the centres of
the balls are free to move in a parabolic path, governed only by gravity and centri-
fugal force; and to thus maintain the rotation of the motor isochronous, without any
adjustment.
The different series of insulated spaces 6 in the conducting cylinder 4 are arranged
so as to produce each a given number of makes and at each rotation of the cylinder in
the derived circuits 18, 19 and 20 of the local generator 21, one pole of which is
connected directly to the body of the cylinder and the other by the various brushes 22,
arranged to bear upon the series of circuit controllers in the cylinder. In each of tho
derived circuits is placed a small resistance 23 and a key 24, and they are all joined
in the primary circuit 25, of the induction coil. As before stated, the internal
resistance of the generator and the primary, is very small; and by means of the
resistance 23, I am enabled to distribute the current in proper relations, whether one
or more of the keys are simultaneously closed.
The main line L includes the secondary 26 of the common primary coil 25, and
this line may be supplied with any of the ordinary systems of telegraphic apparatus
for sending galvanic currents to line. The drawing shows a Morse telegraph with its
devices for graduating the currents,-electro-magnets and condenser.
In Figs. 2 and 3, I have shown respectively a side and plan view of one form of
magnetized tuning fork receivers; in which 27 is a permanent magnet having a core
extension 28, at one pole surrounded by a line wire helix 29, and a tuning fork 30 is
secured to the other pole, being so arranged that the core extension is between the
branches of the fork, as shown. A magnetic shunt or armature piece 31, is adjustably
secured upon one arm of the permanent magnet and serves to regulate the force of
the magnetic field between the fork and core, and enables me to accurately adjust the
tone of the fork. Instead of a magnetic shunt for regulating the magnetic field I may
use any other device performing the same. For instance, another moveable magnet
in the vicinity of the one bearing the fork and which can be adjusted so as to increase
or decrease the intensity of the latter according to the distance of both in relation to
each other.
I would remark that the devices for adjusting the magnetic field are not necessary
if the forks are accurately made, but as I have found difficulties in always securing

page_text: the exact adjustment in constructing the receivers, I can use the adjusting devices for
correcting these errors; but when once adjusted they can remain so without
movement by the operator.
In Fig. 4 I have shown a tuning fork 30, which is itself a permanent magnet
secured to a suitable support and the main line coil 29 is arranged between the
branches of the fork and iron screws, 35, serve to regulate the magnetic field. In
Fig. 5 the fork 30 is surrounded by a permanent magnet 27 having two helices 29 one
on each pole, and the branches of the fork are arranged in the magnetic field between
the adjustable core extensions 28.
Fig. 6 shows the fork provided with a light extension consisting in a light spring
rigidly secured to the leg and preferably having its end 11 formed into a sort of
haminor which is arranged to impinge upon the edge of a resonant body; shown in
this instance as a gong. Suitable means of adjusting the body are preforably provided,
as a screw 13, mounted upon a suitable support connected to the base of the fork as
in Fig. 6, or arranged in proximity thereto. In Fig. 7 I show the body as consisting
of a travelling wheel or cylinder 15, and the end of the extension 10 is formed like a
stilus between which and the drum or wheel 15, passes some suitable material, as a
paper strip, which may be indented by the stylus, to form a record of the message;
or, the stylus may be included in a local circuit and reproduce the message in
characters on chemical paper in a manner well understood; and, at the same time,
the signals may be heard and read by the shocks or blows of the stylus.
In Fig. 8 I have shown another form in which the body or mass 9 is loosely
mounted upon a headed screw 20 secured to the end of the vibrating leg of the fork,
and as the fork vibrates to and fro, the signals can be heard by the rattle of the body
on the screw, In Fig. 9 I have shown the receivers as connected in the main line in
series, and suitable connections 50 are provided by which plugs 51 may be used to
short circuit any one of the receivers, if for any reason it is desired to do so. In
Fig. 10 I have indicated the receivers connected in multiple branches 53, of the main
line with plug connections 50, by which any one may be cut out.
In the diagram Fig. 11, the primary coil 25 is the only part of the transmitting
apparatus shown. The main lino L, including the secondary 26 is branched at the
point 40, one part forming the artificial line L, including a rheostat 41 and magnetic
induction balance 42; and the other branch being connected to the main lino L,
while the bridge circuits 43, include the magnetized receiving instruments 44 ;
suitable resistances being arranged in the branches in a manner well understood.
ог
It is evident that the receiving instruments may be differentialized
arranged in any other well known way to enable the line to be used for the
simultaneous transmission of messages in opposite directions.
It will be evident from the above description that my invention is not limited to
the precise construction or arrangement of devices shown, as those skilled in the art
may embody the principles set forth in other forms and arrangements without departing
from the broad features of my invention.
Having now particularly described and ascertained the nature of my said Inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :
1. The within described method of phono-multiplex telegraph, which consists in
superposing upon the line series of isochronic simplex electric waves, and translating
such waves into audible signals, substantially as described.
2. The method of phono-multiplex telegraph, which consists in producing series of
isochronic simplex electric waves of low potential and transforming such electric
waves into waves of high potential and then translating such high potential waves
into audible signals, substantially as described.
3. The within described method of phono-multiplex telegraphy, which consists in
producing series of isochronic simplex electric waves of low potential, controlling the
rate of their production by the combined forces of gravity and centrifugal force,
transferring said waves into waves of high potential and translating them into

page_text: audible signals by producing variations in a permanent magnetic field, substantially
as described.
4. The within described method of producing isochronic motion which consists in
controlling a motor or a break by means of a parabolic governor, the governor varying
continuously, without interruption, the resistance of an electric circuit.
5. In a phono-multiplex telegraph a metallic cylinder, or its equivalent, having
circumferential rows of recesses in its periphery, and insulated blocks secured in said
recesses flush with the periphery, substantially as described.
6. In a phono-multiplex telegraph, a metallic cylinder having rows of alternate
conducting and insulated metal spaces extending around its periphery substantially
as described.
7. In a phono-multiplex telegraph a metallic cylinder or its equivalent having
series of circuit controlling devices on its periphery consisting of alternate spaces of
conducting and insulating metal, the conducting spaces in each series being equal to
the insulated spaces, substantially as described.
8. In a phono-multiplex telegraph the combination with a motor of a cylinder
driven thereby, provided with series of circuit controlling devices, each series bearing
a fixed relative proportion to the others, of a governor driven by the motor and
controlling the electric circuit of the motor high resistance conductors included in the
circuit and carried by the governor, and regulating devices moving on said con-
ductors under the influence of gravity and centrifugal force only, substantially as
described.
9. The combination with a circuit controlling cylinder of a series of derived or
branch circuits each separately controlled by the cylinder, a single primary, of an
induction coil for all the branch circuits and keys in each branch circuit for opening
and closing them as desired, substantially as described.
10. The combination with a circuit controlling cylinder of a series of derived or
branch circuits each separately controlled by the cylinder, a single generator of low
internal resistance for said circuits, a single primary of an induction coil of low
resistance and keys for opening and closing said circuits substantially as described.
11. The combination with a circuit controlling cylinder having an isochronic
motion, of a series of branch circuits controlled by said cylinder, a single generator
of low internal resistance, a single primary of an induction coil of low resistance for
said circuits, a separate resistance in each branch circuit and keys for opening and
closing each circuit, substantially as described.
12. The combination of a generator the circuit of which includes a motor and an
isochronic governor, of another generator the circuit of which includes circuit con-
trolling devices driven by the motor, whereby the signals produced by said controlling
devices may be isochronic, substantially as described.
13. The combination with a series of derived local circuits, of a cylinder containing
series of circuit controlling devices constructed to produce relatively proportionate
variations in said circuits, a motor operating said cylinder, a governor including a
portion of the resistance of the operating circuit of the motor devices moving under
the influence of gravity and centrifugal force only and controlling the amount of said
resistance whereby the variations may always be maintained in synchronism, sub-
stantially as described.
14. In a phonic or tone telegraph, a receiving instrument consisting of a tuning
fork and coils connected with the line circuit, the fork being permanently magnetized,
substantially as described.
15. A receiving instrument for tone telegraphs consisting of a permanent magnet,
a main line coil connected to the magnet and a tuning fork also connected to the
magnet, whereby the fork will vibrate in a magnetic field, substantially as described.
16. A receiving instrument consisting of a magnet, a line coil connected to one
pole of the magnet, a tuning fork connected to the other pole of the magnet and
a device admitting of adjusting the intensity of the magnet substantially as
described.
17. A receiving instrument consisting of a permanent U shaped magnet, a tuning

page_text: fork attached to one pole of the magnet, a main line coil attached to the other pole,
the core of the latter extending between the branches of the fork, substantially as
described.
18. The method substantially as herein described of producing tone or harmonic
telegraph signals consisting in causing the vibrating receiver to operate mechanically
upon a solid mass or body to produce signals.
19. The method of rendering the vibrations of a tuning fork or reed perceptible by
causing them to act mechanically upon a mass or body of solid material in contra-
distinction to acting upon a mass of air only.
20. A receiving instrument for tone or harmonic telegraphs, consisting of a body
arranged in juxtaposition to a vibrating fork and upon which the fork acts
mechanically to produce the signals, substantially as described.
21. The combination with a vibrating tuning fork, of a body of solid material
arranged within the limits of such vibrations whereby the fork acts mechanically upon
the body to produce the signals, substantially as described.
22. The combination with a vibrating tuning fork of a body of solid material
normally in contact with the vibrating portion of the fork, and adjusting devices,
whereby the resonant body may be acted upon mechanically to produce the signals,
substantially as described.
23. The combination with a vibrating tuning fork, of an extension secured to one
of the vibrating legs of the fork, and a resonant body arranged to be acted upon
mechanically by said extension to produce signals, substantially as described.
24. The combination with a vibrating fork, of a body and adjusting devices, whereby
the body may be adjusted so as to be struck by the vibrating fork when vibrating at
its full normal amplitude only, whereby the effects of induction may be avoided,
substantially as described.
25. The combination with a transmitting instrument sending rapid series of
pulsations to line of an isochronic governor connected to said transmitter, a generator
of low resistance, derived circuits of said generator including the transmitter, a
single primary of low resistance, a main line including the secondary thereof, and
magnetized tuning fork receivers in said line, substantially as described.
26. The combination with a transmitter producing isochronic variations in derived
circuits, of a low resistance generator, a single primary therefor, a main line including
the secondary, and a series of magnetized tuning fork receiver's connected to the line
and switch connections in the line whereby any one or all of the receivers may be cut
out of the line; substantially as described.
27. The combination with a transmitting cylinder having insulated spaces, of a
generator of low resistance, derived circuits therefrom, cach connected to and controlled
by the cylinder resistances and keys in each derived circuit, a single primary for all
the derived circuits, a main line including the secondary and the receiving instrument
in branches of the main line, substantially as described.
28. The herein described method of combined telegraphy, consisting in trans-
mitting graduated Morse signal currents and tone or harmonic signals simultaneously
over the same line wire.
29. The combination with a single line circuit, of means for sending graduated
Morse signal currents and means for sending tone or harmonic signal currents
simultaneously over said line.
1
FAIRFAX & WETTER,
433, Strand, London,
Agents for the Applicant.