IMPROVEMENTS IN ELECTRIC TELEGRAPHS
Year: 1864

page_text: LETTERS PATENT to Pierre Antoine Joseph Dujardin, of 29, Boulevart
St. Martin, Paris, in the Empire of France, Physician, for the Inven-
tion of "IMPROVEMENTS IN ELECTRIC TELEGRAPHS."
Sealed the 20th December 1864, and dated the 8th August 1864..
PROVISIONAL SPECIFICATION left by the said Pierre Antoine Joseph
Dujardin at the Office of the Commissioners of Patents, with his
Petition, on the 8th August 1864.
I, PIERRE ANTOINE JOSEPH DUJARDIN, of 29, Boulevart St. Martin,
Paris, in the Empire of France, Physician, do hereby declare the nature
of the said Invention for "IMPROVEMENTS IN ELECTRIC TELEGRAPHS," to be as
follows:-
When the current of a voltaic battery traversing the wire of an
electro-magnet becomes broken or interrupted, a spark due to the direct
inductive current or extra current developed within the wire of
the electro-magnet flashes between the breaking points; the spark when-
ever the current is rather powerful acts very quickly on the contact
surfaces, which become oxidized in a great measure, thus causing frequent
derangements. This inconvenience, which exists in most electric appa-
ratus, is more particularly observable in telegraphic relays, in consequence
of the weak pressure of the contact surfaces upon one another and of the
slight amplitude of the oscillations.
Different means have been proposed, but unsuccessfully, for sensibly
diminishing these sparks; the following is a new arrangement whereby
excellent results may be obtained.

page_text: A, Fig. 1, electro-magnet, receiving through the medium of a rod R,
oscillating between two abutments, the current of the battery P. The
extreme ends L, L', of the electro-magnet wire communicate with the
two platina wires of a voltameter V, filled with water and of great electric
resistance. When the current from the battery is conveyed through the
rod R into the electro-magnet A, a small part of the current will become
bifurcated and pass through the voltameter; at the moment the current
is broken the extra current is bifurcated likewise, and the resistance of
the air being far greater than that of the voltameter, the greater portion
of the extra current takes the latter course and the spark becomes very
much diminished; it is important to give the voltameter the greatest
possible resistance, so as not to diminish sensibly the energy of the current
which traverses the electro-magnet A, allowing however the extra
current to pass almost entirely through that course. The force of the
extra current depends on the battery, the length of the wire, and the
diameter of the electro-magnet iron, it being impossible to determine
theoretically what is the best resistance to be given to the voltameter,
as practice alone can ascertain it in each particular case.
In my own experiments I have found that a voltameter of 100 miles
resistance (measure in telegraph wire No. 8) almost completely anni-
hilated the sparks produced by the cutting off of the circuit of a 24 cells
Daniels battery, traversing a small electro-magnet of seven miles resist-
ance. The voltameter may be substituted by any suitable resistance
appropriated to the intensity of the extra current, which arrangement
may be applied to all sorts of electric apparatus.
In my Patent No. 1772, dated 15th July 1863, when describing a new
mode of inking the type wheel before or after each printing by means
of a rotating brush or pad, I have indicated that of all substances suitable
for covering said brush, pad, and other parts, practice and experience
have proved hairy or velvet-like fabrics to have the immense advantage
of inking the types most evenly, requiring but very little pressure, the
hair acting somewhat like a brush. This advantage is particularly con-
spicuous when the type wheel is to be inked during its rotation, as is the
case with most printing telegraphs, the slight friction of said hairy
substance requiring much less strain than the ordinary inking plugs or
rollers. Wishing to impart to the type wheel of my printing telegraph
a very rapid rotation, (170 to 200 revolutions per minute,) I have been
led to modify considerably the clockwork escapement whereby said
wheels are made to rotate. In all non-synchronous type printing appa-

page_text: ratus wherein clockwork or a train is made use of, electricity fulfills the
office of disengaging said clockwork movement at every type, so as to
allow the type wheel to advance. This action requires a certain strain,
nor will it permit of a very great rotating speed being attained; I have
conceived the possibility of rendering it self-acting, by making use of
escapements like those in common clocks. Almost all systems of escape-
ments may be employed; that which I commonly use being represented
in Fig. 2. G, peg wheel, keyed on the driving axis which carries the type
wheel, said peg wheel has a tendency to turn in the direction of the arrow;
H, N, I, J, escapement lever oscillating on the point I, and carrying
at H, N, two bevilled pallets arranged as shown at Fig. 2. It will be
easily perceived that the pressure of the pegs on the inclines of the pallets
will tend to force the escapement lever alternately to the right and left,
and cause it to oscillate with greater or less speed according to the power
of the motor, the amplitude of the oscillations or otherwise. The vibrating
motion being imparted to the escapement lever by the clockwork itself,
the electricity has nothing else to perform than to regulate the type by
the rotation of the type wheel in order to keep it in perfect accord with
the transmitter. This regulation is obtained by means of the system
represented at Fig. 1. R, relay rod oscillating between two abutments
and distributing alternately the current of the local battery P to cither
of the electro-magnets A, B; C, D, soft iron pallet oscillating on a pivot.
The pallet tends alternately to right or left according as the current
traverses the electro-magnets A, B, one way or the other. The pallet
C, D, is so connected to the escapement lever H, I, J, Fig. 2, that when
a current traverses the electro-magnets A, B, Fig. 1, the electro-magnetic
attraction becomes much stronger than the pressure of the wheel pegs G,
Fig. 2, upon the escapement pallets and the peg wheel will stop. If the
current is cut off or broken the wheel G begins again to rotate, and does
so until another attraction stops it again.
Now it is easy to comprehend that the relay pallet R, Fig. 1, oscillating
for every current sent by the transmitter will at each type send the
current of the battery P into one of the clectro-magnets A, B, and stop
consequently at every type the rotation of the escapement wheel G, Fig. 2,
supposing however that the time employed for the relay pallet R
traversing the space between the abutments is less than the time necessary
for the clockwork to cause the type wheel to advance a type or character.
Fig. 3 shows the arrangement of a new Invention of currents with
variable discharge to the earth. A, sinuous grooved wheel; E, D, C.

page_text: lever oscillating on point D, and carrying at C a roller, which travels in
the groove of wheel A. If the wheel A is made to turn the platinum
wire fitted at E will oscillate alternately right and left. I, J, G, H,
spring blades fitted at I and G, and tending in consequence of their
electricity to advance and bear upon a metallic abutment F. The two
springs communicate as shown, the one with the line, the other with the
earth. The lever E, D, C, communicates with the zinc pole, and the
abutment F with the copper pole of the same battery. When the lever
D, E, inclines to the right as shown, it raises the spring G, H, and puts
the zinc pole in contact with the earth, whilst the copper communicates
with the line through the spring I, J, and the abutment F. When
the said lever inclines to the opposite side it will raise the
spring I, J, whilst the spring G, H, bears upon the abutment
F. In this position the line is in contact with the zinc and
the earth with the copper, inversely to the usual order. In order to dis-
charge the line after each emission of the current it suffices to give the
platinum wire fitted at E a little less length than the abutment F, so that
every time this wire leaves the one spring it will not raise up imme-
diately the opposite one, while as the two springs are in communication
with the abutment F, the line is discharged. By varying by means of a
screw the length of the abutment F the line will be discharged for a
greater or less length of time.
Lastly, in moving the same abutment to the right or left the current is
rendered at will either longer or shorter than the other, which is some-
times of advantage
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Pierre Antoine Joseph Dujardin in the Great Seal Patent
Office on the 8th February 1865.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, PIERRE
ANTOINE JOSEPH DUJARDIN, of 29, Boulevart St. Martin, Paris, in the
Empire of France, Physician, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Eighth day of August, in the year of our Lord
One thousand eight hundred and sixty-four, in the twenty-eighth year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said Pierre Antoine Joseph Dujardin, Her special licence that I,
the said Pierre Antoine Joseph Dujardin, my executors, administrators,

page_text: and assigns, or such others as I, the said Pierre Antoine Joseph Dujardin,
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 vend, within the United Kingdom of Great Britain and Ireland, the
Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN
ELECTRIC TELEGRAPHE," upon the condition (amongst others) that I, the
said Pierre Antoine Joseph Dujardin, executors or administrators, by
an instrument in writing under my, or their, or one of their hands and
seals, should particularly describe and ascertain the nature of the said
Invention, 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 Pierre Antoine Joseph Dujardin,
do hereby declare the nature of my said Invention, and in what manner
the same is to be performed, to be particularly described and ascertained
in and by the following statement, reference being had to the annexed
Drawing, that is to say:-
This Invention refers to new improvements in electric telegraphs.
When the circuit of a pile or battery traversing the wire of an electro-
magnet comes to be broken, a spark due to the direct inductive current
or extra current developed in the very wire itself of the electro-magnet
bursts out between the breaking points; these sparks when the current
is rather energetic will act injuriously in a great measure on the contact
surfaces, which become oxidized, causing thereby frequent derangements.
This inconvenience, which exists in most electric apparatus, is particu-
larly obvious in telegraphic relays, on account of the feeble pressure
of the contact surfaces upon one another and of the slight amplitude of the
oscillations. Several devices have been proposed, but unsuccessfully,
for the purpose of diminishing sensibly those sparks; the following is a
new disposition which yields excellent results.
A, Fig. 1, represents an electro-magnet, receiving through a rod R,
oscillating between two abutments, the current of a battery P. The
extreme ends L, L', of the electro-magnet wire communicate with the
two platina wires of a voltameter V, filled with water and of great elec-
trical resistance. When the current of the battery is conveyed through
the rod R into the electro-magnet A, a small portion thereof will become
bifurcated, and pass through the voltameter. At the moment the circuit
is broken off, the extra current will be also bifurcated. The resistance

page_text: of the air being far greater than that of the voltameter the greatest
portion of the extra current takes this latter course and the spark is
thereby much diminished. It is important to give the voltameter the
greatest possible resistance in order not to sensibly diminish the energy
of the current which traverses the electro-magnet A, at same time allow-
ing the extra current to follow that course almost entirely. The force
of the extra current being dependent on the battery, the length of the
wire, and the diameter of the iron of the electro-magnet, it is not possible
to determine theoretically what is the best resistance to be given the
voltameter, as practice alone can determine this in each particular case.
In my various experiments I have found that a hundred mile resistance
voltameter (measured by telegraphic wire No. 8) annihilated almost com-
pletely the sparks produced by the breaking of the circuit of a twenty-
four cells Daniel battery, traversing a small electro-magnet at seven miles
resistance. The voltameter may be substituted by any resistance suitably
appropriated to the intensity of the extra current. It is preferable in
certain cases, where it is desired to avoid the effects of the polarizing
current which are manifested in the voltameter at the moment the circuit
is broken off, to substitute for said voltameter resistance coils so con-
structed as to produce no extra current. These coils, which I denominate
neutral resistance coils," may be of various sorts, one consisting of two
wires wound parallel, and so arranged that the current passing through
a wire may return through the next in an opposite direction. It is obvious
that the reciprocal inverse action of the two wires prevents the formation
of the extra current. Single wire coils may still be used by coiling the
wire for a certain number of turns alternately from right to left and left
to right, so that the action of said coils upon one another may be balanced
as exactly as possible. The same result is attained by a suitable union
of two or more separate coils in such a manner that the extra current
produced in one of the coils may be annihilated by a similar extra current
produced in the other, and so forth.
"
In my Letters Patent No. 1772, of July 15th, 1863, when specifying a
new method of inking the type wheel previous to or after each impression
by means of a rotating brush or pad, I mentioned wool & flannel as being
suitable for covering said brush or pad; experience has proved that all
substances having hairy surfaces, such as the various kinds of cotton and
silk velvets, are of especial advantage for inking the types evenly, and
require but
very little pressure, such hairy surfaces acting like a brush;
this advantage is particularly obvious when it is desired to ink the type

page_text: wheel during its rotation, as is the case in most printing telegraphs, the
slight friction of said hairy substance produces much less strain than the
common inking pads or rollers. The most advantageous arrangement in
this case is represented at Fig. 4.
A, common type wheel, with types engraved on its periphery; B,
cylindrical tube, into which slide freely a piston C, carried by a button
or knob D. The bottom of the tube is covered with a velvet or hairy
tissue. A layer of fatty ink I also filis the lower part of the tube B. As
may be seen, the velvet acts like a brush, and the piston C causes at will
the ink to penetrate the weft of said velvet or hairy tissue. If the
impress is too deeply inked it will suffice to raise the piston C, and the
atmospheric pressure will force the ink immediately within the tube.
The velvet may be sewed, glued, or otherwise fixed to the bottom of the
tube B. I usually make use of the following device, which yields good
results. V, X', is a metallic spring clip, the two parts Y, Z, of which
may be brought more or less close to each other by means of the screw L',
this clip fits tightly on the tube and presses the velvet firmly against the
side of the tube as shown. This mode of inking has the advantage of
requiring but a slight pressure on the types, the ink being laid with a
perfect regularity, and so that the operator may easily vary at will the
amount of ink required for the impression.
Now wishing to impart to the type wheel of my printing telegraph a
very speedy rotation (150 to 200 revolutions a minute), I have been led
to modify considerably the clockwork escapement whereby this wheel was
made to rotate. In all non-synchronous printing telegraphs where a
train of clockwork is made use of, and also the type apparatus, the dis-
connection of the clockwork is effected for each character by electricity,
in order to allow of the type wheel progressing. This action requires
certain strain, and does not permit of a very speedy rotation.
a
According to this Invention I render it self-acting, by the use of escape-
ments similar to those of ordinary clocks. Almost all kinds of escape-
ments, anchor, fusee, & other escapements, will answer the purpose.
The one which I preferably make use of is represented at Fig. 2.
G, pin wheel, fitted upon the type wheel, carrying shaft rotating in
the direction of the arrow; H, N, I, J, escapement lever, oscillating on
the point I, and carrying at H, N, two bevelled pallets arranged as
shown. It will be readily understood that the pressure of the pins on
the inclines of the pallets will tend to carry alternately to right and left
the escapement lever, and cause it to oscillate with more or less speed

page_text: according to the power of the motor & the amplitude of the oscillations.
The oscillating motion being imparted to the escapement lever by the
clockwork, the electricity is simply used to regulate one character by
one, the rotation of the type wheel to the extent of a type or character
at each time, in order to render it perfectly in accord with the trans-
mitting agent, which object is obtained by means of the system repre-
sented at Fig. 1. R, relay rod oscillating between two abutments, and
distributing alternately the current from the local battery P to the electro-
magnets A, B; C, D, soft iron pallet oscillating on a pivot. This pallet
is carried alternately to right and to left according as the current passes
into one or other of the electro-magnets A, B, Fig. 1, & the electro-
magnetic attraction being far greater than the pressure of the pins (of
the type wheel G, Fig. 2,) upon the escapement pallets the pin wheel
will stop. Should the current be broken the wheel G shall begin again
to rotate until it is stopped by the next attraction. Now it is obvious
that the relay pallet R, Fig. 1, oscillating for each current transmitted
thereto, will at each character send the current of the battery P into
one of the electro-magnets A, B, and consequently stop at every type
or character the rotation of the escapement wheel G, Fig. 2, supposing
however, as may be well understood, that the time employed by the relay
pallet G, Fig. 1, to traverse the space between the abutments is less
than the time necessary for the clockwork movement to cause the type
wheel to advance one character or figure.
Fig. 3 shows the arrangement of a new Invention for variable dis
charge currents.
A, sinuous grooved wheel, similar to that of French type telegraphs;
E, D, C, lever, oscillating on the point D, and carrying at C a roller,
which travels in the groove of wheel A. If the wheel A is made to rotate,
the platina wire fitted at E will oscillate alternately to right and left.
I, J, G, H, spring blades, fitted at I & G, and having on account of
their elasticity a tendency to bear on a metallic abutment F. The two
springs communicate, as shown, the one with the line, the other with
the ground. The lever E, D, C, communicates with the zinc pole, and
the abutment F with the copper pole of the same battery. When the
lever D, E, inclines to right, as shown, it raises up the spring G, H, sets
the zinc pole in contact with the ground, whilst the copper pole communi-
cates with the line through the medium of the spring I, J, and the abut-
ment F. When the same lever inclines to the other side, it raises the
spring I, J, whilst the spring G, H, bears upon the abutment F. In

page_text: this position the line is brought into contact with the zinc, and the ground
with the copper, inversely to the usual order. After each emission of the
current, it suffices to give the platina wire, fitted at E, a little less length
than the abutment F, so that every time the wire releases the one spring
it does not immediately raise the opposite one, while the two springs being
in communication with the abutment F, the line is discharged. By
varying length of the abutment F by means of a screw, the line may
be discharged for a greater or less time. Finally, by carrying to right
or to left the same abutment, a current is at will rendered more or less
long than the other, which is sometimes productive of advantages. A
somewhat grave inconvenience will sometimes occur in practice with all
telegraphic apparatus, which invert alternately the direction of the
current on the line, yet never interrupting the same during the trans-
mission. It is impossible, in fact, in damp weather, when the relays are
very sensitive, even when the relay of the expediting station is within
the circuit of the line, to ascertain at the said expediting station whether
the other station receives duly the forwarded despatch.
Supposing that London sends a dispatch, to Edinburgh, and that the
latter from any cause whatever does not receive the communication, and
desires to make the London station aware of it. If the line be damp, and
Edinburgh takes its communication from the ground, the London relay
will not for all that cease to proceed by reason of the deviations on the
line. If Edinburgh send on the line a succession of currents alternately
inverted, it will even happen that the London relay continues to proceed
by reason of the difference in damp weather of the force of the current
at the departure and at the arrival stations. In order to obviate this
inconvenience, I dispose my apparatus during the transmission as repre-
sented at Fig. 5. A, invertor of the current, as before described; D,
line battery; C, relay; B, single-stroke electric signal apparatus.
It
will be readily understood by the inspection of the Figure that the current.
starting from one of the poles of the line battery (the zinc pole in the
Figure) will pass through the wire of the electro-magnet of the signal
apparatus previous to going to the invertor. In this manner so long as a
current is sent along the line, either positive or negative, a current
(always of the same polarity) will traverse the electro-magnet of the
signal apparatus, which maintains its armature constantly attracted. If
the receiving station does not receive the communication exactly, and
sends currents along the line at the same time that the expediting station
goes on transmitting, said currents will take the following direction :-

page_text: from E to F, across the relay F to G, H, thence across the battery D,
then from J to K, K to L, across the signal apparatus, and, lastly, to
the ground through the medium of the spring N of the invertor. If the
antagonistic spring of the signal apparatus B is suitably regulated, when
a current of opposite polarity traverses the electro-magnet the armature
will be released; attracted anew, if the current proceeding from the
opposite station ceases or changes its direction, and the sound of the
hammer striking on the bell will awake the attention of the transmitting
operator.
Having thus described the nature of my Invention, and the manner in
which the same is to be carried into effect, I claim,-
First, employing in electric apparatus a resistance suitably appropriate,
as described, for giving passage to most part of the extra current, which
diminishes considerably the sparks at the breaking points of the circuit.
Secondly, employing for inking the type wheel of printing telegraphs,
silk, cotton, wool, or other hairy substance, serving either as a stationary
or moveable brush or pad, the ink being fed through the weft of the
cloth, and applied by the hairy surface on the types, whatever may be
the form or arrangement of the inking apparatus.
Thirdly, employing in the clockwork movement, whereby the type
wheel is made to rotate, escapements so disposed as to work spontaneously
through the simple action of the driving spring or weight, as described,
the action of the very current itself serving to regularize this rotation one
character at a time.
Fourthly, employing a new variable discharge invertor, as described.
Fifthly, employing any sounding or warning organ or apparatus
arranged as described, and working at the expediting station at the
command of the receiving station.
In witness whereof, I, the said Pierre Antoine Joseph Dujardin,
have hereunto set my hand and seal, this Twenty-sixth day of
January, in the year of our Lord 1865.
.P. A. J. DUJARDIN. (L.S.)