IMPROVEMENTS IN TELEGRAPHIC APPARATUS
Year: 1862

page_text: LETTERS PATENT to William Spence, of 50, Chancery Lane, in tho
County of Middlesex, Patent Agent, for the Invention of "IMPROVEMENTS
IN TELEGRAPHIC APPARATUS."-A communication from abroad by Jean
Didier Digney and Bastien Théodore Digney, both of Paris, in the
Empire of France, Manufacturers of Telegraphic Apparatus.
PROVISIONAL SPECIFICATION left by the said William Spence at the
Office of the Commissioners of Patents, with his Petition, on the
8th July 1862.
I, WILLIAM SPENCE, of 50, Chancery Lane, in the County of Middlesex,
Patent Agent, do hereby declare the nature of the said Invention for "IMPROVE-
MENTS IN TELEGRAPHIC APPARATUS," (being a communication to me from abroad
by Jean Didier Digney and Bastien Théodore Digney, both of Paris, in the
Empire of France, Manufacturers of Telegraphic Apparatus), to be as
follows:-
This Invention relates to improvements which are particularly applicable to
the dial telegraph known as the "French railway telegraph." Some of the
improvements have for their object an increased certainty in the working of
the apparatus without changing the manipulation thereof or adding sensibly to
its complexity and an avoidance of the necessity for constantly regulating the
same, which has hitherto caused much uncertainty, loss of time, and many

page_text: mistakes; and some additional arrangements of the apparatus have for their
object the use of the apparatus, if required, not only to indicate the successive
letters which compose the words of a despatch, but also to print them on a
band of paper; and some other arrangements of the apparatus are intended to
facilitate the manipulation with regularity and rapidity by any person not
accustomed to the work. Some of the improvements relate to the commutator
and others to the indicator. As regards the commutator, in ordinary "French
telegraphs" the oscillations of the lever have the effect of alternately producing
a transmission and causing a suspension of the current of electricity, and the
currents are transmitted always in the same direction; but in the commutator
under the present Invention, as in that, described in the Specification of. the
Patent granted to me, and bearing date 15th February 1858 (No. 279), a
transmission of the current of electricity is produced by each oscillation of the
lever, and these currents are produced alternately in opposite directions. For
this purpose neither of the two poles is invariably connected with tho earth;
it is by the sole action of the lever that each of these poles is put in relation
alternately sometimes with the earth sometimes with the line wire, whilst
the other pole, on the contrary, is at the same moment put in relation with
the line wire, then with the earth, the line wire going besides to the station in
correspondence so as to connect it with the earth by means of the wire of the
bobbins of the indicator. The arrangement of, the parts of this reversing
commutator may be varied in order to adapt it to the circumstances under
which or the apparatus with which it is required to be used. As regards the
indicator, it differs from the indicator in ordinary dial telegraphs in the
manner of arranging the electro-magnet intended to determine the oscillation of
the armature which drives the escapement; this electro-magnet is no longer
an ordinary electro-magnet, it is an electro-magnet connected to one of tho
arms of a permanent magnet. The main object of the improvements in the
indicator is to obviate the necessity for constant regulation of the instrument.
In ordinary indicators the oscillatory movement of the armature is determined
by two opposite forces, one of which is due to the transmission of the current
of electricity, the other resulting from the action of a spring; but in the
present indicator there is no counteracting spring, it is the electricity itself
which, being reversed in its direction, disturbs the equilibrium of forces and
causes the oscillation of the armature. The printing of despatches by means
of the said indicator is effected by different arrangements of apparatus, in
one of which the impression is produced by the working of the electro-magnet,
which can only come into action by the sufficient prolongation of one of the
contact pieces which, in the manipulation, cause the passing of the letters.

page_text: Instead, however, of producing the impression by the prolongation of the
current emitted by the letter intended to be transmitted, it might be produced,
as it has been done already, by the action of the supplementary battery, the
circuit of which would only be interrupted by a particular contact piece when
the operator lowered the handle in the notch of the letter which he desired to
print.
And the Invention consists, lastly, in arrangements applicable to the system
of commutator with keys, known as that of Messieurs Froment and Bréguet,
for the purpose of rendering it capable of reversing as well as otherwise to
simplify its construction. The principal improvement herein consists in the
application of the lever with two arms; each oscillation of which causes a
current in a different direction. The oscillations are produced by means of an
excentric, the button of which drives the double-acting lever, and is arranged
so as to be capable of removing to a greater or less distance from its centre of
motion in order to vary the length of the oscillations.
Another arrangement is that of two cylinders of wood or other noncon-
ducting material, one with contact pieces in connection with the line and the
other with the earth, and two springs to each connected to the zinc and copper
poles respectively, so as to cause a transmission of currents alternately in
Opposite directions.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said William Spence in the Great Seal Patent Office on the 7th
January 1863.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
SPENCE, of 50, Chancery Lane, in the County of Middlesex, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Eighth day of July, in the year of our Lord One
thousand eight hundred and sixty-two, in the twenty-sixth year of Her reigu,
did, for Herself, Her heirs and successors, give and grant unto me, the
said William Spence, Her special license that I, the said William Spence, my
executors, administrators, and assigns, or such others as I, the said William
Spence, my executors, administrators, and assigns, should at any time agree
with, and no others, from time to time and at all times thereafter during the
. term therein expressed, should and lawfully might make, use, exercise, and
5 vend, within the United Kingdom of Great Britain and Ireland, the Channel
Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN TELEGRAPHIC
APPARATUS," being a communication from abroad by Jean Didier Digney and

page_text: Bastien Théodore Digney, both of Paris, in the Empire of France, Manu-
facturers of Telegraphic Apparatus, upon the condition (amongst others) that
I, the said William Spence, by an instrument in writing under my hand and
seal, should particularly describe and ascertain the nature of the said Inven-
tion, and in what manner the same was to be performed, and cause the same
to be filed in the Great Seal Patent Office within six calendar months next
and immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said William Spence, do hereby declare the
nature of the said Invention, and in what manner the same is to be performed,
to be particularly described and ascertained in and by the following state-
ment, reference being had to the Drawings hereunto annexed, and to the
letters and figures marked thereon (that is to say):-
This Invention of "Improvements in Telegraphic Apparatus" relates to
improvements which are particularly applicable to the dial telegraph known
as the French railway telegraph. Some of the improvements have for their
object an increased certainty in the working of the apparatus without
changing the manipulation thereof, or adding sensibly to its complexity, and
an avoidance of the necessity for constantly adjusting the same, which has
hitherto caused much uncertainty, loss of time, and many mistakes. And some
additional arrangements of the apparatus have for their object the use of the
apparatus, if required, not only to indicate the successive letters which com-
pose the words of a despatch, but also to print them on a band of paper.
And some other arrangements of the apparatus aro intended to facilitate the
manipulation with regularity and rapidity by any person not accustomed to
the work. Some of these improvements relate to the commutator, and others

page_text: interrupted each time that the lever is brought back against the opposite
contact piece which is connected to the indicator apparatus. Each of these
alternate transmissions and interruptions of the current has the effect of pro-
ducing at a distance the release of a half tooth of the escapement wheel of the
indicator at the station in correspondence.
But in the commutator under the present Invention, as in that described
in the Specification of the Patent granted to me, and bearing date the 15th of
February 1858 (No. 279) a transmission of the current of electricity is produced
by each oscillation of the lever, and these currents are produced alternately in
opposite directions. For this purpose neither of the poles is invariably connected
with the earth; it is by the sole action of the lever that each of these poles is
alternately put in relation sometimes with the earth and sometimes with the
line wire; whilst the other pole, on the contrary, is at the same moment put
in relation with the line wire, then with the earth, the line wire going besides
to the station in correspondence so as to connect it with the earth by means of
the covered wire of the bobbins of the indicator.
I now proceed to describe the different modifications which have been
applied, under the present Invention, to the commutator in the former Patent,
herein-before referred to, in order to adapt it for producing the results now
required.
The first arrangement of apparatus for this purpose is represented in Figs.
1, 2, and 3 (Sheet I. of the accompanying Drawings.
Fig. 1 is a plan or horizontal view of the commutator complete; Fig. 2 is
a side elevation of the same; Fig. 8 is a section of the dial Hand of the
sinuous grooved wheel J on the axis of the handle.
As will be seen, on reference to Fig. 1, the sinuous groove wheel J, in
which gear on the left hand the stud G fixed to the double-armed lever
which determines the transmissions of the current towards the line wire, and
on the right hand the stud G' fixed to the lever 4, 11, intended to establish the
communication of the line wire with the apparatus of the indicator has only
thirteen sinuosities, the dial having twenty-six divisions corresponding with the
twenty-six signs required for the twenty-five letters of the alphabet and one
for the mark+.
The two arms K', K, K¹, and , k, l, of the lever on the left hand are
connected at by an insulating connection. The fulcrum K of the lower
arm is connected to the copper pole of the station battery; the fulcrum k of
the upper arm is connected to the zinc pole. The contact pieces m and n³ are
connected to the line wire; the contact pieces m³ and n, on the other hand,
are connected with the earth.

page_text: The relative positions of the fixed dial; the wheel with a sinuous groove
which is turned by the handle, and the studs G and G which gear with the
sinuous groove, have been regulated in the following manner:-When the
tooth of the handle is to the right of the mark +, the stud G gearing
with the sinuous groove is midway between the mark + and the top of a
waving thereof, that is to say, that the two arms K, K', and k, k, of the lever
are in the middle position in relation to their respective contacts; at the
same time the stud G' is in the hollow of a waving, and consequently the
lever 2, ', is caused to rest against tho contact pieco o of the indicator.
When the handle is moved from the mark + towards the letter A at the
moment when the handle reaches the middle of the space which separates
them the stud G reaches the top of the waving, and on pushing back towards
the left, the connection, it causes the arms K and of the lever to rest
against the contact pieces m and n. The circuit is then closed, and a positive
current is transmitted through the lino wire to the indicator of the station in
correspondence; at the same time, on the other band, the stud G2 is in the
middle of a waving, and the lever 1, 1, drawn by it touches nothing. When
the handle is moved from the mark + towards the letter A the stud G descends
the length of a waving, and is thus brought back from left to right, and at the
moment when the handle arrives before the letter A, this stud is found
between the top and the hollow of the waving, and tho levers K' and ' aro
midway between the contact pieces m, m³, and n, n', without touching any of
them; the communication between the line and the station battery is then
broken. At the same time the stud G¹ is at the top of the waving, and con-
sequently the lever l' is again further separated from the contact piece o. If
the handle be further turned from A towards B, when it reaches the middle
of the space which separates them, the stud G will be in the hollow of a
waving, and consequently the arms K' and will be caused to rest against
the contact pieces m³ and n', and the circuit will be again closed, but in an
opposite direction, and it will be a negative current which will pass to the
lino; at the same time the stud G will have again descended to the middle of
the waving, and the lever will have again approached towards the contact
piece o, but without touching it. When, finally, the handle shall have arrived
over the letter B, the stud G will be in the middle of a waving and K' and k
will be out of contact, whilst the stud G¹ having reached the hollow of a
waving, the lever drawn by it will be caused to rest against the contact piece o;
at this moment, then, the communication between the station battery and the
line wire will be interrupted, but, on the other hand, the communication will
be established between the indicator at the station and the line wire by means

page_text: of the contact piece o, which is connected to the indicator at the station and
the lever '.
By continuing tho motion of the handle from B towards C, the same effects
will be gone through, that is to say, before the handle reaches C a positive
current will be transmitted to the line wire; then before it reaches Da
negative current, and as to the lover drawn by the stud G, it will only touch
the contact piece o¹ every other time at the moment when the handle passes
before the letters B, D, &c., and before the mark +.
The second arrangement of apparatus for the aforesaid purpose (see Fig. 4)
only differs from that just described in that the arms K, K', and k, k³, of the
oscillating lever, instead of being connected, the former to the copper pole,
and the latter to the zinc pole, of tho battery, are respectively connected, the
former to the line wire, and the latter with the earth, and that the contact
pieces m and n' are connected to the copper pole, and the contact pieces m'
and n, to the zine pole of the battery.
The third arrangement of apparatus for the aforesaid purpose is represented
at Fig. 5. The preceding arrangement is susceptible of the modifications
represented in this Figure, in which the function performed by the right-hand
lever 1, in Fig. 1, is more simply performed by a projection or stud g, con-
nected to the indicator apparatus at the station, and placed in an intermediate
position between the contact pieces m and m', and below the arm K¹, of the
left hand oscillating lever, in such a manner that this arm K' rubs against
this projection or stud g, and establishes a communication with the indicator
apparatus only at the moment when the said arm K' touches neither of the
contact pieces m and m².
The fourth arrangement of apparatus for the aforesaid purpose is represented
at Fig. 6, in this same Sheet 1. In this arrangement the two arms of the
left-hand oscillating lever instead of being jointed at, are connected in a
rigid manner at this point, but always insulated the one from the other.
There is only one centre of oscillation at K, by which the arm K, K¹ is, as
in the former arrangement, connected to the line wire. The arm k, l, is
connected at k, with the earth by a wire which admits of its being changed
in position. As is obvious, since the two arms in their oscillations are
carried in contrary directions, it becomes necessary to change the function of
the contact pieces n and n³, and to connect n to the zinc pole and n' to the
copper pole. This arrangement answers equally well with the substitution of
the before-named projection or stud for the right-hand lever 1, 7. Moreover,
by dispensing with the joint and the second centre of oscillation, which
existed at k, it offers the advantage of preventing difficulties which might

page_text: arise in these adjustments during the working, and which might interfere
with the accurate agreement of the contact pieces, and render the working of
the apparatus less regular and certain.
The fifth arrangement of apparatus for the aforesaid purpose is represented
at Figs. 7 and 8 (Sheet 2), in which the apparatus is illustrated as applied
to two stations, Nos. 1 and 2 in correspondence. It possesses the following
peculiarities:-The two arms of the left-hand lever are again connected in a
rigid manner, but so as to form a right angle, the top of which is their com-
mon centre of oscillation K, o. The cross piece k, which carries the blade
of the arm k, l, of this bent lever, is insulated from the other arm K, K, K',
by pieces of ivory ³, . The said arm K, K°, K', is connected by the
frame of the commutator with the line, the arm k, k¹, is connected with tho
earth, but no longer directly, only through the medium of the indicator of the
station itself.
In order to put in action the lever 1, 1, intended to produce the contacts
for the indicator apparatus, the following arrangement is in substitution for
the stud G, by which the sinuous groove wheel was acted upon. On the outer
circumference of this wheel are formed 13 or 26 notches, (the Figures only
shew 18) which the catch g at the upper end of the lever 1, 2, may enter,
being pressed towards the notches by the spring r. These notches are
arranged so that the catch g may not fall out of them again, and that con-
sequently the blade will not touch the contact piece except at those
moments when the levers K' and are midway between their respective
contact pieces. The commutators of the two stations in correspondence
Nos. 1 and 2 are alike, except that the contact pieces m and n of the station
No. 1 being connected to the copper pole of the battery of this station, and
the contact pieces m³ and n¹ to the zinc pole; the reverse is the case in the
station No. 2, that is to say, that in the station No. 2 m and n are con-
nected to the zinc pole, and m', n', to the copper pole of the battery of this
station.
In Figs. 7 and 8 the apparatus at the station No. 1 is supposed to be
arranged for sending a message to station No. 2, the commutator of which is
at rest, and has its right-hand lever 1, 1, resting against the contact piece
connected with the indicator, while both arms of its left-hand lever are out of
contact. The moment represented is that wherein the arm K' of the oscil-
lating lever of the station No. 1' touches the contact piece m of the copper
pole of its own battery, and the arm & touches at the same time the contact
piece n' of the zinc pole, and consequently the apparatus at the station No. 1
is sending a positive current to the line wire. The arrows indicate the

page_text: direction of the current starting from the copper pole (C), passing first by
the commutator and the indicator of station No. 2, thence by the earth (T)
to the indicator of station No. 1, and through the medium of the contact
piece o, and the arm k, k', and the contact piece n³ to the zinc pole of the
battery of station No. 1, in which the two extremities are reunited.
In this arrangement the two indicators are in the circuit, and the operator
at the station from which the message is sent sees his own indicator reproduce
the message which he sends, and he can control it. Should his correspondent
wish to interrupt him, he would be made aware of his intention by the jerking
stoppages produced on the needle of his own indicator; indeed, as soon as the
operator at the station No. 2 himself puts his commutator in motion, the
lever 1, 1, of this latter being set in motion, will, at rapidly succeeding
intervals, cease to touch the contact piece o, consequently the course followed
by the currents transmitted by the commutator at station No. 1 becoming for
an instant cut off at this point, will not be able to reach the indicator at
the same moment, the continuous operation of which will be thus interfered
with.
The arrangement just described has the advantage of giving increased
certainty in the manipulation; indeed, owing to the manner in which the
two arms K,, of the oscillating lever are combined, they may be equal, and
have accurately corresponding motions. Moreover, the manner of working
the left-hand lever 2, 1, is quicker, and the contacts of this lever with the
contact piece o are shorter, the effect of which is to increase the certainty of.
the manipolation, inasmuch as these contacts tako place in a more precise
manner at the same moment in which the levers K' and are just midway
between their respective contact pieces. It is further to be observed that, by.
the form of the notches on the sinuous groove wheel, this wheel constitutes,
together with the catch g in which the lever 1, 1', terminates, a ratchet wheel,
which prevents it from, returning, and consequently places an obstacle in the
way of ordinary causes of disturbance, which often result when an inexperienced
operator, having passed over one or several divisions the letter which he seeks,
wishes to cause the handle to return, this produces irregular and improper
contacts, and disarranges the indicator.
The sixth arrangement of apparatus for the aforesaid purpose is represented
in Figs. 9 and 10 (Sheet 8). In this arrangement the two arms of the left-
hand oscillating lever, instead of directly causing the contacts which deter-
mine the emissions of a current, act simultaneously sometimes on the
springs R, R, and sometimes on the springs R³, R². These springs are
arranged so as to be capable of leaving in a state of rest, say, R', R

page_text: against the contact piece Z, and R1, R2, against the abuttal ✗, the latter
being insulated. The contact piece Z is connected to the zinc pole of the
station battery; the two contact pieces m and m³ form only one contact in
effect, and are connected to the copper pole of the battery, and the contact
pieces n and n¹ to the zinc pole through the intervention of *Z. The
springs R¹, R², are connected by their point of attachment to the line wire,
and the springs R, R', to the left-hand button of the indicator apparatus.
The station No. 2 being intended to receive the message, the two springs R'
and R³ of this station touch the contact piece C¹, which is connected to
the copper pole of the battery C¹. Z of this second station, and the
springs R1, R2, rest against the insulating abuttal; on the other hand, at
the station No. I the double contact m, m³, is connected to the zinc pole,
and n, n', like C, are connected to the copper pole of this second station.
The springs R', R³ 2, are also connected to the line wire, as the springs R²
and R'1 to the indicator apparatus, but by the right-hand button. When
the operator at station No. 1 works his commutator, at the moment when
the arm K' of the oscillating lever pushes back the spring R³ towards the
right hand, and causes it to rest against the contact piece m connected to the
copper pole, the other arm k¹ in the same manner causes the spring R¹ 1 to
rest against the contact piece n' connected to tho zinc pole, and then a positive
current is transmitted to the line wire, and it follows the course indicated by
the arrows.
This arrangement, in comparison with the preceding, has the
advantage of dispensing with the mechanism of the indicator, owing to the
contacts at C' and Z'; it also obviates the noise occasioned by such mechanism ;
but while it gives more freedom to the experienced operator, it has the
inconvenience for the inexperienced of allowing backward movements.
The different arrangements of apparatus herein-before described may be
varied by combining in a different manner the several elements of which the
same is composed, henco the ratchet or retaining wheel, which serves to work
the lever of the indicator apparatus, shewn in Figs. 7 and 8, may be used
in the preceding arrangements. It is also to be understood that in all theso
arrangements the two indicators, or one only, may be put in circuit at will,
except in the arrangement shewn in Figs. 9 and 10, in which the indicators
of the two stations are necessary in the circuit.
DESCRIPTION OF THE INDICATOR.

page_text: the electro-magnet and its appurtenances; Figs. 14 and 15 represent each an
additional arrangement, intended to put in motion at the required moments
the printing mechanism described in the Specification of the Patent herein-.
before referred to No. 279, 1858).
As will be evident, on reference to Figs. 11, 12, and 18, this improved
indicator differs from the indicator of the ordinary dial telegraphs in the
manner of arranging the electro-magnet intended to determine the oscillations
of the armature which drives the escapement. This electro-magnet is no
longer an ordinary electro-magnet; it is an electro-magnet connected to one
of the arms of a permanent magnet, in a manner similar to the system
employed by Messrs. Siemens & Halske in their needle electro-magnetic
telegraph.
A, A², is a permanent magnet arranged at right angles, one arm of
which, A', is vertical, and the other, A, horizontal. To the vertical arm A',
which, let it be supposed, is polarised North, is fixed a cross piece of soft iron.
On this cross piece are fixed the two bars of soft iron of an ordinary electro-
magnet with two arms B, B'. The two other extremities of these bars are
connected to two slides of soft iron N and N', which may be brought nearer
together or put farther apart by means of adjusting screws without ceasing to
be magnetically connected to the said bars of soft iron, of which they are the
prolongations in the return of the square. The extremity of the horizontal
arm A of the permanent magnet, which is of the contrary pole, that is South,
has a slot formed in it to receive the axis or centre of oscillation of the
armature of soft iron a common to the two electro-magnets B and B³. The
whole system of mechanism is arranged behind the dial of the indicator, and
above the clockwork, in such a manner that the electro-magnet B, B¹, mny
be parallel to the plane of the dial, and that the armature a (the plane of
which is also parallel to that of the dial) oscillates on its axis between the
two slides N, N¹, and determines, by the oscillations of its lower part & in
the ordinary manner, the action of the escapement wheel, which carries on
its axis the needle of the dial of the indicator.
The action of the clockwork, the arrangement of the escapement, and of
other parts of the apparatus being the same as in ordinary indicators, except
the greater spreading of the dial caused by the projection formed by one of
the two electro-magnets, it is not necessary to give any detailed description
of the same, and it will suffice to explain the action of the armature under
the influence of the reversed currents, which are transmitted from the com-
mutator of the station in correspondence through the line wire to this
improved indicator.

page_text: By means of the arrangements now to be described it will be understood
that when the apparatus is at rest, that is to say, when no current coming
from the line wire is caused to animate the bars of soft iron of the electro-
magnet B, B', these bars, which are connected to the north pole A, are
influenced by this pole, of which they are the continuation, and in this
manner the two slides N, N', are both polarised North. For the same reason
the armature a, which oscillates in the slot formed in the south extremity of
the permanent magnet, and is connected thereto by its axis, is influenced by
this extremity, and polarised South by it. The extremity of this armature
polarised South is thus situated between the two slides N and N¹, both
polarised North; it is then attracted by both, and if, by the aid of the
adjusting screws V, V, these two slides are brought into such a position that
these two contrary actions balance each other, the armature will remain in
equilibrium, and if by any cause the armature becomes disturbed from this
state of equilibrium, and carried towards one of the slides, for example, the left-
hand slide N', the predominance of attraction of the latter will retain the
armature so long as there is no change in the state of things, but as soon as,
from any cause whatever, the attraction of the other slide predominates, the
armature will be drawn towards it, and reciprocally if the predominance of
attraction be disturbed.
Now this is what occurs under the influence of alternative currents in
contrary directions transmitted from the line wire by the commutator of the
station in correspondence. Let it be remembered that when the handle of the
commutator is at the mark + no current passes to the line wire; that when
it proceeds from the mark + to the letter A, a positive current is transmitted
to the line wire; that when the handle advances over another division, and
passes to the letter B a negative current, and so on alternately. The parts
of the indicator are similarly disposed, so that when the handle of the com-
mutator is at the mark + the needle of the dial is also at this mark, and at
the same time the armature is carried towards the left-hand slide N'. In
consequence of these positions of the parts at the moment when the handle
of the commutator has advanced from the mark + towards the letter A,
and a positive current has thus been transmitted towards the indicator in
correspondence, the influence of this current will tend to polarise tho right-
haud slide N North, which is already so polarised by the influence of the per-
manent magnet A, A'. These two influences will then concur to magnetise
the said slide strongly in the same direction of North, while on the other hand
the polarisation South caused by the current in the left-hand slide N' will
neutralise wholly or in part the effect which it derived from the permanent

page_text: magnet A, A, and if it predominates will replace it by a polarisation South.
The conditions of equilibrium in the action of the two slides on the armature
which remains polarised South will be interrupted, the slide N strongly
magnetised North will exert a powerful attraction on the armature magnetised
South, and the left-hand slide N¹ on the other hand will attract with much less
force or cease to attract, or even repel the said armature, which will then be
carried from left to right towards the slide N.
When the handle of the commutator has continued its progress from A to
B, and has transmitted an opposite current, the contrary effect will be
produced, and the armature will be repelled 'from right to left, and so on.
The movements of the armature are, however, limited by two screw abuttals
r, r, which only allow the part t thereof to oscillate to a convenient extent.
The position to be given to the two slides, so that they may produce a suffi-
cient effect on the armature, is determined besides by the two adjusting screws
V, V, herein-before referred to.
I will now proceed to shew how this modification, applied to the ordinary
indicator of a dial telegraph, obviates the necessity of adjustment and increases
the certainty in action.
In ordinary dial telegraphs when in working them a letter has been passed
a step backwards cannot be taken without disturbing the agreement between
the indicator and the commutator; in fact, by returning backwards, the
interruption of the current which had been caused to succeed to the emission
which had produced the passing of the letter intended to be signalled (or
reciprocally) causes in the indicator a new oscillation of the armature, and
consequently causes the needle of the said indicator to advance the distance
of another letter, which is thus in advance of the commutator, and con-
sequently out of agreement with it.
Now the effect under the present Invention is as follows:-If after
having brought the handle to the letter A, and having just passed by that
letter, without, however, advancing it to the position which would produce tho
négative current required to signal the following letter B, the operator returns
the handle so far backwards as to bring back the oscillating lever of the com-
mutator into the position which it had just quitted, and which had the effect
of transmitting a positive current to the line wire, this is what would happen,
a new positive current would be transmitted to the line wire and to the
indicator. But as this current is of the same kind as that which it succeeds,
there will be no change in the polarisation just produced in the slides of the
electro-magnet. The armature will be then attracted afresh towards the same
slide N against which it was previously carried, and it will experience no

page_text: change of position, neither will tho escapement wheel, nor the needle of the
dial. By this means a frequent cause of difficulty is obviated, and the incon-
venience arising from irregularity of operation prevented. But this is not all.
The much more serious inconvenience resulting from the difficulty of adjusting
ordinary dial indicators, that is to say, of putting the force of the counter-
balancing spring in relation with the magnetic force developed by the electro-
magnet, is completely removed in the greater number of cases, and con-
siderably reduced in others.
:;
In ordinary dial indicators, indeed, the oscillatory movement of the armature
is determined by the exertion of two opposite forces; on the one hand the
attraction resulting from the magnetism due to the transmission of the
current, on the other by the action of a spring, which ought to be weak enough
to yield to the attractive power of the electro-magnet, and strong enough (as
soon as the exertion of this power ceases) to overcome the force of the
remaining magnetism, and bring back the armature to its former position. It
is then necessary to modify the tension of this spring at each change produced
in the force of the magnetisation of the electro-magnet, not only on account
of the more or less resistance from the line wire, but also of the greater or less
intensity of the transmitted current according to the atmospheric circumstances.
In the arrangement just described there is no counterbalancing spring, it is
the electricity itself, which being reversed, causes sometimes in one direction,
sometimes in another, a disturbance of the equilibrium; whence results the
oscillation of the armature. It is immaterial with what degree of force this
arinature is displaced, provided that it be great enough to overcome the resist-
nuce of the escapement. If the apparatas has been adjusted for the most
unfavorable case, that is to say, for the least amount of magnetic force that
will work it, its operation will be rendered certain for all other cases without
any change in its adjustment.
DESCRIPTION OF DIFFERENT ARRANGEMENTS FOR THE PURPOSE OF ADAPTING THE
IMPROVED INDICATOR JUST DESCRIBED TO THE PRINTING OF DESPATCHES.
Fig. 14 (Sheet 4) combined with Fig. 11, already referred to, shews one of
these arrangements in which the impression is produced by the working of tho
electro-magnet, which can only come into action by the sufficient prolongation
of one of the contact pieces which, in the apparatus of the commutator,
cause the passing of the letters. E, E, are two pairs of electro-magnets
distinct from each other. The second electro-maguet, the play of which is
intended to produce the impression, ought to be more powerful than the
other E, the function of which is to break the circuits of the local battery

page_text: affected by the latter. The electro-magnet E is itself worked by a local
battery for the purpose, and the circuit of which is only broken under the
circumstances now to be explained. The covered wire of the bobbins of the
electro-magnet E is connected to the copper pole C of its said local battery
Z, C, by one of its extremities f¹; the other extremity f' is connected to the
lower stem of the armature a of the indicator, Fig. 11. The zinc pole of the
said battery is connected by a fork to each of the two abutting screws r, T³,
between which the said stem of the armature oscillates. The prolongation b
of the armature e of this same electro-magnet E oscillates between two
abuttals u, u; it is furnished with a small spring i which strikes against the
insulating button and presses it out of the way before it can touch the upper
abuttal u. This latter is connected to the zinc pole Z of the second local
battery Z, C, affected by the electro-magnet E¹, and the body of the said
armature e is connected to one of the extremities f' of the bobbins of the
second electro-magnet E¹, the other extremity f' being connected to the
copper pole C of the said second local battery; it is the prolongation b' of
the armature e of the second electro-magnet E' which carries the printing
hammer and puts in motion the small mechanism for advancing the paper; in
other respects the mechanism for printing is the same as that described in the
Specification of the Patent herein-before referred to. The effect of this
arrangement is as follows:-Each time that, under the influence of the
currents in opposite directions emitted by the commutator, in order to seek a
letter, the prolongation & of the armature of the indicator is caused to touch
either the one or the other of the screws r, r; the effect of these contacts will
be to close the circuit of the local battery Z, C, in the electro-magnet E; but
this closing of the-current will be already behind the action of the electro-
magnet of the indicator; a certain period of time will be required for the
development of the magnetic effect in the electro-magnet E and for the effect
of its attraction on its armature. This period of time will also be increased
by the resistance opposed to the spring i, which will only occur when the
stem b, after having overcome this resistance, has reached the contact piece u,
when the circuit in the second electro-magnet will be closed, and its armature
will come into action in its turn. It will be evident then that if the commu-
tator be worked with sufficient rapidity the contacts at u will have no time to
become produced, and that the circuit of the electro-magnet E¹ for putting the
printing mechanism in motion will not have time to become formed; but that
if, on the contrary, the handle of the commutator be stopped before any
letter, and that thus time be allowed for the electro-magnet E to gain force,
and the stem 6 of its armature to overcome the resistance of the spring to

page_text: reach the contact piece u, and to give certainty to the action of the electro-
magnet E³, the hammer at the end of its armature will produce the impression
of the said letter in the indicator.
Fig. 15 represents a modification of the arrangement now to be described.
The electro-magnet E, instead of being actuated by a local battery, is put in
action by a portion of the current proceeding from the line wire to the electro-
magnet of the indicator, which portion is introduced at the end of the covered
wire of the first bobbin. This portion of the current is, moreover, incapablo
of being established by the branch wire f until after the stemt of the armature
of the indicator to which this wire f is connected causes, by its contact with
either the screw r or the screw r³, a reunion between the said wire f and the
wire f' of the bobbins of the electro-magnet E, the other extremity of which f
is connected with the earth at T, and thus tends to close the circuit in the
electro-magnet E. In other respects everything occurs as in the preceding
arrangement. The first auxiliary electro-magnet E might be of the same
kind as the electro-magnet B of the indicator; but in that case the abutting
screw u ought to be connected, like the screw u, to the zino pole of the local
battery, and the prolongation of the armaturo e ought to be furnished below
with a second spring, like the spring , and resting against an insulating
button, in order that the effects produced above might bo also produced
below, since the armature of this electro-magnet is alternately carried in one
direction and the other, according to the direction of the current.
Figs. 16 and 16 represent in plan and elevation the electro-magnet thus
modified. Instead of determining the impression by the prolongation of tho
current emitted for the letter intended to be transmitted, this impression might
be produced in a manner analogous to that used in ordinary printing appa-
ratus, by the action of a supplementary battery, the circuit of which should
only be closed by a particular contact piece when the operator lowered tho
handle in the notch of the letter intended to be printed. Supposing, for
example, that, as shewn in Fig. 17, the handle of the commutator is furnished
underneath with two springs communicating permanently, the one, No. 1, with
the line wire, the other, No. 2, with the earth; if, moreover, between each of
the spaces separating the letters there are contact pieces, insulated from the
frame and connected alternately, the one to the copper pole of a supplementary
battery and the other to the zinc pole of this same battery, and if the space
between theso springs is equal to that between the before-named contact
pieces, it will follow that when the handle is at the mark + the spring No. 1
will be against a copper pole contact piece, and the spring No. 2 against a
zinc pole contact picco; but if the handle pass from the maik + to the

page_text: letter A the contrary will take place. So long as the operator does not lower
the handle so as to bring the springs against the said contact pieces the
supplementary battery will have no effect, but as soon as the handle is lowered
the circuit of the supplementary battery will be closed and in a different
direction, according to whether the division is of an odd or an even number.
This supplementary current being likewise of the same direction as that trans-
mitted to the right of the corresponding letter, there will result from each of
them an increase of magnetic action. If, then, the hammer intended to
produce the impression be connected to the prolongation of the armature of
an electro-magnet which is in the circuit of the currents issuing from the line
wire, and if the tension of its counterbalancing spring be regulated so that it
cannot be overcome by the normal current serving to seek the letter, but that
t yields to the increased strength of the said current, it will be obvious that
he printing of the letters will only be produced at the will of the operator,
nd when he lowers his handle in a manner analogous to that employed in the
rinting telegraph described in the Specification of the Patent herein-before
referred to.
APPLICATION OF THE MODE OF MANIPULATING IN ORDER TO REVERSE THE CURRENTS
IN THE KEY-BOARD COMMUTATOR SO AS TO PRODUCE MECHANICALLY, AND
CONSEQUENTLY WITH REGULARITY AND ALSO WITH THE REQUIRED RAPIDITY,
THE SUCCESSIVE EMISSIONS OF THE ALTERNATE CURRENTS, THE PROLONGING
OF WHICH IS ALONE INTENDED TO DETERMINE THE PRINTING OF THE LETTER
IN CORRESPONDENCE.
1
In order that in the arrangements herein-before described, in which the
rinting of a letter is intended to be produced by the prolonging of a current
ransmitted towards the line wire, this prolonging may not take place with
urrents which serve only to seek the letter; it it necessary, as has been
een, that the successive emissions of the currents should be produced with
ufficient rapidity and in a regular manner; but that supposes an experienced
perator. In order, therefore, to make such regularity of operation more
ertain and more independent of the skill of the operator, a key board
ommutator with the above described mode of reversing the currents applied
hereto is employed. This will be understood from the following description.
f the modifications applied to the key-board commutator known as that of
Messrs. Froment and. Bréguet, for the purpose of making it reversing, and
therwise simplifying its construction.
Fig. 18 (Sheet 5) is an elevation of a key-board commutator with the
nprovements under the present Invention applied thereto; Fig. 19 is a plan

page_text: or horizontal view of the same; Fig. 20 is a transverse vertical section of the
apparatus in the line 1, 2, of Fig. 18; Fig. 21 represents detached the
variable excentric which produces the oscillations of the reversing lever;
Fig. 22 represents the wheel for the contacts communicating with the
indicator.
As will be seen from these Figures, the principal improvement herein
consists in the application of the lever with two arms, each oscillation of
which causes a current in a different direction. In order to produce these
oscillations, instead of a sinuous groove wheel, there is employed an excentric,
the button of which drives the double-acting lever L, and is arranged so as
to admit of its being removed to a greater or less distance from its centre of
motion, in order to vary the length of the oscillations. The indication is
obtained by either one or the other of the arrangements herein-before
described with reference to the reversing dial commutator. It may be
produced either by means of a stud against which the lever is caused to
strike at required moments, or by means of a wheel with 26 or 13 notches
or projections; for example, like that shewn in Fig. 22. This wheel is fixed
on the axis of the cylinder at the free end of the latter, and in such a position
that the spring J only touches the said wheel I at the moments when the
lever L is between its contact pieces, and when, consequently, no current is
transmitted to the lino wire.
The manner of arranging the key board is also to be observed. Instead of
motions as of swinging levers, there are motions as of pistons, the rods of
which are caused directly to stop, when lowered, the pegs on the surface of
the cylinder moved by the clockwork, which occupy the rank corresponding
with that of the letter marked on each of the keys. As will be further
evident, each of these rods by being lowered brings down the swinging frame
to which is connected the stop which holds the cylinder moved by the
clockwork, and consequently allows the cylinder to turn until the said rod
is met by the correlative peg.
Another arrangement is that represented in Fig. 29, which may replace
both the oscillating lever and the excentric which drives it. This arrangement
consists of two cylinders of wood, or other non-conducting material, mounted
on the axis of the cylinder. Each of these is furnished with thirteen contact
pieces let into grooves on their surface. The thirteen contact pieces of the
first of these two cylinders are connected to the line wire, and the thirteen
contact pieces of the second are connected with the earth. Against the
surface of the first cylinder press two springs, one of which is connected to
the copper pole, and the other to the zinc pole, with this peculiarity, that

page_text: when one meets a contact piece, the other is on an insulating piece, and
reciprocally. The same arrangement exists on the other cylinder, but in a
contrary direction, whence it results that when the first spring connected to
the copper pole touches one of the contact pieces of the first cylinder which
are all connected to the line wire on the other cylinder, the spring connected
to the zinc pole will touch at the same moment a contact piece connected
with the earth. At this moment the two other springs will be on an insulating
piece. Immediately afterwards the two first springs will be, on the contrary,
on an insulating part, and the two others, of which one, that of the first
cylinder, is no longer connected to the copper pole but to the zinc pole, will
press on a contact piece communicating with the line wire, whilst the other,
connected to the copper pole, will press on a contact piece connected with the
earth, consequently the currents emitted will be alternately in contrary
directions. In order to vary the duration of the contacts, the form of a
trapezium may be given to the contact pieces, and the springs by being
mounted on a small carriage may be put in the presence of metallic arcs
greater or less in size.
Having thus described the nature of the said Invention and in what manner
the same is to be performed, I hereby declare that what I claim as of tho
Invention, communicated to me from abroad as aforesaid, is the several
combinations of parts of apparatus herein-before described, for the purposes
described.
In witness whereof, I, the said William Spence, have hereunto set my
hand and seal, this Fifth day of January, in the year of our Lord One
thousand eight hundred and sixty-three.
Witness,
GEORGE BEDELL COULCHER,
50, Chancery Lane,
Law Stationer.
WILLIAM SPENCE. (L.S.)