IMPROVEMENTS IN TELEGRAPHY AND IN APPARATUS THEREFOR."
Year: 1876

page_text: LETTERS PATENT to Peter Jensen, of 33, Chancery Lane, in the County of
⚫ Middlesex, for the Invention of "IMPROVEMENTS IN TELEGRAPHY AND IN
APPARATUS THEREFOR." A communication from abroad by Paul La Cour, Vice-
President of the Royal Meteorological Institute, Copenhagen.
Sealed the 21st July 1876, and dated the 29th February 1876.
PROVISIONAL SPECIFICATION left by the said Peter Jensen at the Office of
the Commissioners of Patents on the 29th February 1876.
""
PETER JENSEN, of 33, Chancery Lane, in the County of Middlesex. "IMPROVE-
MENTS IN TELEGRAPHY AND IN APPARATUS THEREFOR.' A communication from abroad
by Paul La Cour, Vice-President of the Royal Metercological Institute, Copenhagen.
These improvements have reference to transmitting and receiving isochronously
vibrating electric currents through a telegraph conductor according to La Cour's
system of telegraphy, patented 2nd September 1874, No. 2999, and are as follows:-
In order to give the required continuity to the isochronously vibrating currents
passing through a telegraph line, it is useful to let the tuning fork of the transmitting
apparatus be in constant vibration against its contact, and then to cause the trans-
mission of an isochronously vibrating current by simply closing the telegraph wire
by the wire of the apparatus. This constant vibration of the tuning fork may be
effected by applying an apparatus constructed like the receiving instrument in
La Cour's aforesaid system, but connected as follows:-One end of the wire conductor
forming the electro-magnet and the wire reels is led to one pole of an electric
battery, and the other end is connected either to the tuning fork or to its contact,
the other of these two is carried to the other pole of the battery. The apparatus
will, when so arranged, be kept in uninterrupted vibration, for as the tuning fork
touches the contact a current will be produced in the conductor through which the
tuning fork will be extended, and consequently go away from the contact, so that
the current ceases, the legs of the tuning fork will therefore go back and the contact
will be touched again, and so o11. The tuning fork will thus continue to vibrate
and simultaneously the conductor of the apparatus will be traversed continuously
by isochronously vibrating currents in the same musical measure as corresponds
with the note of the tuning fork. This current can be sent directly through a
telegraph line. For this purpose, instead of letting the current from the apparatus
return directly to the pole of the battery the connection between them is by a
simple mechanism interrupted, and then immediately again re-establish through

page_text: the telegraph line and back through earth. The isochronously vibrating current
may thus at will be made to pass through the telegraph wire or to pass directly to
the battery, and by this mechanism then the passage of the current through the
wire and its duration may be determined, as by the ordinary telegraph key the
passage of an ordinary current through the telegraph wire is determined. Such a
continuously vibrating current may also be applied to other purposes than telegraph-
ing, for its regularity is so great that for, say, thousand currents, there is not so
much divergence or difference as one current from the normal number of the
apparatus in question. Applied as a regulator for clockwork it is for many
purposes superior in accuracy to a well compensated pendulum.
The next part of this Invention is as follows:-Having arranged La Cour's
apparatus in connection with a battery as herein-before described, the telegraph
line may also by induction be traversed by isochronously vibrating currents. The
constantly intermittent currents in the apparatus arranged as described may there-
from be led into suitable induction reels, and thus in the other conductors or lines
of the latter induce isochronous currents alternately positive and negative. By
connecting to or inserting the said lines into the telegraph line their currents may
be made to traverse it. The advantages of this mode are, namely, the greater
simplicity and facility wherewith the currents are made to enter the telegraph line,
and wherewith consequently the telegram is transmitted, also the greater number
of such currents which simultaneously may pass through a conductor without
mutually interfering with one another, also a further diminution in the loading of
the telegraph wires because of these currents. Telegraphing may with these
currents be effected at any point of the line irrespective of all other correspondence
through it, provided only that two transmitters work simultaneously with the
same note.
For all the herein-before described improvements the wire reels in the middle of
which the legs of the tuning fork are situated may in many cases be dispensed
with, because the resistance in the line which the inducing current has to traverse
is not great.
The next part of this Invention is as follows:-When it is desired for a receiving
instrument that the duration of the local current, which is produced in it when
actuated, shall be exactly as great as the duration of the actuating vibrating current,
then the tuning fork on the receiving apparatus must have as small inertia as
possible, in order that it may come quickly into vibration and likewise quickly
stop vibrating. The tuning fork must hence be as small as possible. This is best
accomplished by so constructing the apparatus that both the legs of the tuning fork
are placed in the same wire reel wherein they can freely vibrate, and by letting the
stem of the tuning fork (which is of soft iron) be continued back through the
middle of another wire reel and bending it once more, terminating in two legs or
branches which are just outside the legs of the tuning fork. When then a current
which traverses both the reels produces, for instance, north magnetism in the legs
and south magnetism in the branches, then the legs will mutually repel each other,
and because of the attraction towards the branches be extended or forced apart,
thus fulfilling the same object as La Cour's aforesaid apparatus but with a tuning
fork of very small size.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by the
said Peter Jensen in the Great Seal Patent Office on the 29th August 1876.
PETER JENSEN, of 33, Chancery Lane, in the County of Middlesex. "IMPROVE-
MENTS IN TELEGRAPHY, AND IN APPARATUS THEREFOR." A communication from
abroad by Paul la Cour, Vice-President of the Royal Meteorological Institute,
Copenhagen.
These improvements have reference to La Cour's system of telegraphy, patented
2nd September 1874, as a communication to Peter Jensen, and numbered 2999.

page_text: The main idea of that system, as there described, consists in transmitting isochro-
nously vibrating currents of different speeds of vibration; the receiving instruments
being so constructed that when several such instruments are traversed by the currents,
such instruments only will come into action which are tuned to give the same speed
of vibration as the current or its components, while the otherwise tuned instru-
ments will remain at rest; the action of the acting receiving instruments is to
cause contact in a local circuit, the current of which can then produce some desired
effect. It is in the said Specification, No. 2999 of 1874, stated that this may be
done in various ways, and while stating therein that various equivalent appliances,
such as tuning forks, rods, plates, chords, strings, or pendula may be used, the said
appliances being of various length, thickness, or configuration, so as to give each a
certain number of vibrations per second, answering to a certain musical note; a
special choice of these appliances, and their arrangement is made, the main point
being as therein stated, that the appliances at the receiving station are so chosen
and arranged that each one of them comes in vibration when its note corresponds
with the speed of vibration of the arriving current or one of its components, but
otherwise not; and that the appliance through coming into vibration causes
closing in a local circuit, which can print, write, or otherwise signify the corre-
sponding sign.
While strictly adhering to these aforesaid main points, the present Invention
consists in various improvements in the details of the arrangement, all as herein-
after described.
In order to give a very continuous, even, and steadily vibrating character to the
current on the transmitting station, the wires of that instrument, which in the aforesaid
Specification is described as the receiving instrument, represented by Figures 3, 4, 5,
and 6, on the Drawings accompanying the said Specification, may be connected
with a battery as shewn on Figure 1 of the accompanying Drawings to this present
Specification. A, Figure 1, is the aforesaid receiving instrument, now applied as a
transmitting instrument, and B is the battery. The current from the battery
traverses the wire L, the electro-magnet M, M, the wire reels T, T, the tuning fork,
1, 8, 7, and the wire l, B. The electro-magnet M, M, and the tuning fork, n, p, 8,
thus become magnetized, and the tuning fork becomes extended, so that contact
between the leg n, and the contact piece P, ceases. The current is thus interrupted,
the legs of the tuning fork go back, contact with the contact piece P is re-established,
the current arises again, the tuning fork is extended, and so on. The tuning fork thus
vibrates constantly, producing an even note, and the wire conductors are traversed
by an isochronously vibrating current of great regularity, corresponding with the
note of the tuning fork.
Various such instruments may thus be applied, the tuning forks of which are
tuned to give different notes; but as it in many cases may be desirable with
facility to be able to set an apparatus so as to produce any desired note, and a
current vibrating in unison therewith, the wire reels T, T, may be omitted, thus
leaving the tuning fork quite free, and providing the tuning fork with sliding
weights in order thereby to alter the pitch of the note. An instrument of this sort
is shown in side elevation at Figure 2, and in plan at Figure 3.
The tuning fork n, p, s, is fixed in the block H, arranged on the bed plate, but
insulated therefrom. The poles S and N of the electro-magnet M, M, are close by
the legs n, s, of the tuning fork, so that they may exert attraction to them, and
thereby cause an extension of the tuning fork legs; the tuning fork may be either
of hardened magnetised steel, or of soft iron. The wires of the electro-magnet are
connected to the insulated screws and 1². A double armed lever V, VI, turning ou
the fulcrum pinx, can be shifted in position by means of a set screw v, which acts
against the long arm V, while the spring R exerts a counterpressure against the
other or short arm V1 that is fitted with the platina contact c; the point of contact
on the leg n of the tuning fork being also covered with platina. From a battery
the one pole is carried to the screw, whence the current traverses the electro-
magu̟ct M, M, to the screw ¹, is thence carried back through the screw to the

page_text: bed plate, the lever V, V1, the contact piece c, the tuning fork, the screw 7, and
thence to the other pole of the battery. If now by means of the set screw the
position of the contact be regulated relatively to the tuning fork then the extension
of the latter will break the contact, the current will cease, the legs of the tuning
fork will go back, the current arise again, and so on as above described; an even
note, and a corresponding isochronously vibrating current being produced. By
changing the position of the sliding weights U, U, on the legs of the tuning fork
I alter the note of the latter, and as the legs are provided with suitable marks any
desired note and correspondingly vibrating current may be obtained by shifting the
sliding weights U to the required marks.
Such a continuously vibrating current may also be applied to other purposes
than telegraphing, for its regularity is so great that for, say thousand currents,
there is not so much divergence or difference as one current or impulse from the
normal number due to the apparatus in question. Applied as a regulator for
clockwork it is for many purposes superior in accuracy to a well compensated
pendulum.
The next part of this Inventeur is as follows:-When several such vibrating
currents are thus at disposal they may be made to enter the telegraph wire in
many different manners, either singly or several, simultaneously; but the most
suitable choice is such a one which causes the telegraph wire to be traversed by a
vibrating current, consisting of constantly changing or alternate positive and
negative impulses, as it may be expressed, or in other words, a vibrating current,
the impulses of which constantly change direction. This may be done either by
letting the aforesaid vibrating currents which are at disposal produce induction
currents in the telegraph wire, or by another mode of connection as shall be
presently described.
By induction it may be done as shown at Figure 4, by letting the vibrating
inducing current produced by the apparatus A. and battery B traverse the inducing
wire,, of the induction roller J, J, while the telegraph line goes through the
induced wire c, c¹, of the same roller. The production of each impulse in the
wire,, then causes an impulse in the wire c, c¹, in the same direction, and the
stoppage of each impulse in the wire, l, causes an impulse in the wire c, c¹, in the
other direction. The wire c, c¹, is thus traversed by double the number of impulses
as 7, 1, but with constantly changing direction. By means of a key, whereby the
line from Qto R can be established and broken as desired, the vibrating current
from c to c¹ may at will traverse either the key c or the telegraph line L, L, which
in that case must form a circuit closed to carth. But if on the contrary the tele-
graph line is in constant connection with the earth at the receiving station only
the key C may be left out, c may be carried to earth, and the currents arising in
the induction roller J may at will be sent off by means of a key, which as desired
connects and breaks the line from c¹ to the telegraph line.
As, however, direct electrical currents in most cases are to be preferred for
induction currents, the transmission of the vibrating currents here arranged with
alternate positive and negative impulses in the following manner, and as shown at
Figure 5. When the vibrating current, which is produced as described by means of
an apparatus, and a battery is led through the electro-magnet M of a quite similar
instrument A, thereby that it is led in at the screw ², and led out at the screw k,
then the tuning fork of this instrument if tuned to give the same note as the
current will get into vibration and continue to vibrate. There will hence constantly
be an intermittent connection between the screw (which is connected with the
tuning fork) and the screw 12 (which is connected with the contact). At Figure 5
the first instrument and the battery are for clearness sake left out, and their purpose
is exclusively to cause the screws and to be in intermittent mutual connection
by means of the vibrating contact of the tuning fork leg n with the platina
contact c. The telegraph line L, L, L3, L, (which through other stations and
instruments forms a closed circuit with earth) will, when the present vibrating
current is not about being transmitted pass through L², C, C, L³, which latter thus

page_text: is traversed partly by the currents which from other instruments or stations are
sent through the line, and partly by the currents produced by the batteries B and
B², which I shall now describe. The line L1, L2, communicates with the continuation
line L³, L, by the wire C¹, C, but also through L², g, h, L, this latter connection is
again divided, one branch going off at g to h through the battery B, and another
through the intermittent connection g, 1, 12, h, and in the wire connection h, L³ is
furthermore inserted another battery B2, which has less electro-motor power than B,
and the current of which moves in an opposite direction in the wire B2 to B¹. It
will now be understood that the action of this system is as follows:-
1. When the key C is closed each current arriving at L2 and L³ from the
batteries B and B will chiefly disperse itself through the wire connection L², C, C¹, L³,
while only a very small part of this current will traverse the telegraph line. In
this case consequently no current is sent from the present instrument through the
telegraph line, but the latter is not interrupted, so that all other correspondence
may pass through it undisturbed.
2. When the key breaks the line C, C¹, we must consider two different move-
ments. The one movement is that in which contact takes place between the tuning
fork branch n and the contact c, and consequently connection i, g, 1, 1, h; and the
other movement is that in which no direct connection takes place here.
A. In the first movement the main part of the current from the battery B will
traverse g, 11, 12, 1, while a comparatively small part will from g and h traverse the
telegraph line. On the contrary the battery B will send a current through the
telegraph line, partly through 1, 12, l, g, and partly through h, B¹, g. Let this
current have the force &¹ and pass from right to left, that is from L' to L'.
As B' is
B. But in the moment when there is no direct connection between 1 and the
telegraph line passes exclusively through L, L², g, B¹, h, B³, L³, L
stronger than B, and contrary to it, a current 82 will pass through the telegraph
linc from left to right, hence from L' to L. It can be arranged beforehand to
make this current force as large as (but opposite to) s by diminishing or increasing
82; this can be done by inserting larger or smaller resistances R in the line B, h,
without thereby sensibly altering the current force s¹. It is possible to make s¹
exactly as large as and opposite to s before commencing to telegraph without
disturbing the other correspondence through the line. For this purpose while the
telegraph line remains closed through L', L², C₁, C, L³, L', the connection between
Land g, and between B2 and L³ is interrupted, I unite with B2 through a galvano-
scope and a rheostate, the resistance of which represents the resistance of the
telegraph line, and all the apparatus connected. If now constant closing between
and be established the galvanoscope will give a stroke to one side, and if the
connection be broken between and it will give a stroke to the opposite side.
Having thus by variation of the resistance in the rheostate R taken care that these
strokes are of the same size, the tuning fork is put into vibration, causing inter-
mittent contacts with the contact piece c; the latter is then by its regulating screw
set so that the needle of the galvanoscope points to zero. Then the impulses &¹
and & are not only equally large and opposite, but also of saine duration, and the
instrument is then ready for telegraphing, wherefor the connection is established, as
shewn at Figure 5. It will now be seen that at such times as C remains closed no
currents are transinitted from the present instrument through the telegraph line, and
at such times as C is kept open the interposed system will send impulses alternately
positive and negative through the telegraph line, which impulses are of equal
strength and equal duration, as graphically represented at Figure 6, in all cases the
telegraph line is not interrupted for a moment, so that all other correspondence can
be carried on simultaneously and undisturbedly.
Telegraphing may hence with these currents be effected at any point of the line
irrespective of all other correspondence through it provided only that no two
transmitters work with the same note simultaneously. If a vibrating current only
be desired, the impulses of which all go in the same direction, the battery B° may
be left out, for then the current from the battery B will alternately traverse the

page_text: linch,,, g, and the telegraph line. If it be not considered an object to avoid the
interruption of the telegraph line the connection C¹, c, may be left out, L.carried
to earth and a key inserted at L³, which at will can close and break the connection
from the described system of transmission to the telegraph line L. Finally it may
be added that a special instrument and battery are not required for keeping the
tuning fork l, n, in constant vibration against c, for if the line connection h,, on its
way be made to traverse the electro-magnet M, M, then the currents in this connec
tion will keep the tuning fork n, l, in constant vibration because they always
vibrate.
The next part of this Invention is as follows:-When it is desired for a receiving
instrument that the duration of the local current, which is produced in it when
actuated, shall be exactly as great as the duration of the actuating vibrating current,
then the tuning fork on the receiving instrument must have as small inertia as
possible.
I shall now proceed to describe this improvement, which is connected with the
receiving instrument described in the Specification of my aforesaid Patent,
No. 2999 of 1874. The improved instrument also only comes into vibration when
- traversed by a current which either in itself vibrates in a measure corresponding with
the tuning of the receiving instrument, or which among its components contains
such a current while the instrument remains at rest in all other cases and causes
closing of a local current by coming into vibration. But the improved instrument
possesses the advantage that it is very quickly acted upon by an arriving identically
vibrating current, and that it very quickly ceases to act when the current ceases to
traverse it.
Figure 7 is a perspective view of the apparatus. A bar of soft iron is at one end
notched out as a small tuning fork. The bar is bent at right angles so as to pass
through two wire reels T¹, T", and so that its other end S, with its two rigid
branches and 81, enclose the legs n¹, n, of the tuning fork without touching
them, the latter also being free in the interior of the wire reel T¹.
When an
ordinary current passes through the reels T, T, from Lto L, the iron bar becomes
so magnetized that the legs n¹ and n of the tuning fork partly mutually repel
each other and partly are attracted by the branches s¹ and s¹, so that the tuning
fork consequently from both reasons is extended. When the current ceases the
iron bar becomes demagnetized and the branches go back. The behaviour of the
instrument as regards a vibrating current is hence quite the same as the receiving
instrument described in the aforesaid Specification 2999 of 1874, but it has the
advantage that the tuning fork may be inade very small, whereby its moment of
inertia is diminished. The desired closing of a local current takes place in the
following manner :-The reels and the tuning fork are by the insulator i separated
from the frame A, A, whereon a double armed lever V is so fastened that one arm
can be moved by means of the set screw v, the spring R exerting a counterpressure
against the other arm, so that the platina contact is placed very close to the inner
side of the branch n¹ without, however, touching the latter when the latter is at
rest, but only when the tuning fork comes into vibration. A battery, the poles of
which are connected to and will then be closed when the tuning fork vibrates
but otherwise not. When using a vibrating current with impulses of alternate
directions, it must be noticed that as both sorts of impulses produce an extension of
the tuning fork it will come into vibration when timed to give as many complete
oscillations (that is there and back) per second as there are impulses altogether
(positive plus negative) per second, so that consequently the receiving tuning fork
is one octave higher than the tuning fork which according to the described method
has produced the current. But the instrument may on the contrary be so arranged
that while an impulse in one direction causes them to be extended, an impulse in
the opposite direction causes them to come together. This can be done by exchanging
the reel T and the part of the iron bar therein for an electro-magnet and a steel
magnet, which constantly has one and the same sort of magnetism in a pair of
stiff branches, in the same place as s¹, s¹¹. In this case an arriving current traversing

page_text: the reel T¹, and consisting of impulses of alternate directions, will produce the
alternate extension and coming together of the branches n', n", of the tuning fork,
hence consequently put them into vibration, when this current is produced in the
described manner with a tuning fork of the same note as that of the receiving
apparatus. From the foregoing it will be obvious that this mode of telegraphy
(which is a further developement of my Patent No. 2999 of 1874), is able to
accomplish the following, which will be understood by reference to Figure 8, viz. :-
When a line forms a closed circuit T, L, L³, T, either with itself or through earth,
then at any points transmitting systems i, i, i, and receiving systems 7, 1, 7, may be
inserted, and these systems and apparatus neither when working nor while at rest
interfere with or interrupt the line, and each transmitting apparatus may at
pleasure cause the whole line to be traversed by a vibrating current consisting if
desired of alternately positive and negative impulses of equal strength and duration,
and in a measure corresponding to the attuning of the transmitting apparatus; and
further, each receiving apparatus is only actuated when a corresponding apparatus
on the line is at work, either alone or together with others and the influence shows
itself thereby that the receiving apparatus closes a local current, which can do what
is desired according to circumstances. To this may be added that as the receiving
instruments are not sensitive to ordinary currents, and as the impulses with
changing character (positive and negative) of the transmitting instruments are so
short that they are not felt by ordinary telegraphing and measuring instruments,
because the changing impulses mutually destroy each others effects before they
get time to indicate themselves, one may besides in the same line insert transmitting
and receiving instruments which work with ordinary currents, if only they be of
such a construction as not for a moment to break the line. The grouping of the
instruments i, i, i, and r, r, r, here shewn is of course perfectly at random, and they
may be distributed at several different stations or be concentrated at the two
terminal stations of the line. According to this system then the same is accomplished
as if each corresponding transmitting and receiving instrument were united by a
separate wire line, while in reality only one single wire line is used, that is a
multiplex system.
And having thus fully described the nature of this Invention and modes in which
it may be carried into effect, I declare that I claim as the herein described
improvements,
First. Producing an evenly vibrating current by means of a tuning fork, so
arranged relatively to a contact as by touching it to close an electric current and by
a here from resulting electro-magnetic effect to be again removed from the contact,
so that the tuning fork of itself continues to vibrate and to produce an isochronously
vibrating current, all substantially in the manner herein set forth.
Second. The application of a self-vibrating tuning fork with sliding weights,
whereby the tone may be varied as desired so as to produce a current the impulses
of which have a desired measure of vibration, also the application of a fine regulating
mechanism for the contact for giving each impulse a desired duration in proportion
to the impulse intervals, all substantially in the manner herein set forth.
Third. Causing a vibrating current to induce currents in another wire line,
whence they then at will may be made to traverse the telegraph line without for a
moment necessitating a break therein, all substantially in the manner herein set
forth.
Fourth. The mode here described with reference to Figure 5 of connecting a tele-
graph line, the key C, the batteries B1 and B2 and an intermittent wire line l, n, c, 12,
whereby the telegraph line at will may be traversed by a vibrating current, the
impulses of which are of equal strength and of equal duration but shifting direction,
without for a moment being obliged to break the telegraph line, all substantially as
set forth.
Fifth. So arranging a tuning fork or equivalent vibrating appliances in combina-
tion with a wire reel, an electro-magnet, or a steel magnet on a receiving station,
that the tuning fork is only affected when among the currents which traverse the

page_text: telegraph line, one current be found which has a speed of vibration corresponding
to the tuning fork or its octave note as set forth.
Sixth. Causing a vibrating receiving tuning fork or equivalent appliances to
indicate its vibration thereby that it produces closing of a local current through a
contact, all substantially in the manner set forth.
Seventh. Inserting in a telegraph line different transmitting and receiving
instruments, constructed substantially as here described, so that each receiving
instrument is only affected by impulses which are derived from the corresponding
transmitting instrument, whereby a multiplex system is obtained, which, according
to circumstances, may be applied in many different ways.
In witness whereof, I, the said Peter Jensen, have hereunto set my hand and
seal, this Twenty-ninth day of August, in the year of our Lord One thousand
eight hundred and seventy-six.
PETER JENSEN. (L.S.)