IMPROVEMENTS IN ELECTRIC TELEGRAPH TRANSMITTING, RECEIVING, AND RECORDING INSTRUMENTS AND IN CLOCKS
Year: 1870

page_text: PROVISIONAL SPECIFICATION left by Sir William Thomson at the
Office of the Commissioners of Patents, with his Petition, on the
23rd November 1870.
I, Sir WILLIAM THOMSON, Knight, of Glasgow College, Doctor of
Law, and Professor of Natural Philosophy in the University and
College of Glasgow, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN ELECTRIC TELEGRAPH TRANSMITTING, RECEIVING, AND
RECORDING INSTRUMENTS AND IN CLOCKS," to be as follows:-
My present Invention consists partly in improvements in the con-
struction and design of my receiving or recording instrument (described
in the Specification No. 2147, 1867), partly in appliances to that instru-
ment, adding new functions to it, and partly in methods for sending.
messages.
:
1. My first improvement consists in a better form and disposition of
the light receiving coil and of the magnet used to produce the magnetic.
field in which it moves. For brevity I shall call these parts of the
apparatus the signal coil and the signal magnet respectively. I now,
give the coil the symmetrical form of a long rectangle, and support it,
so that it is moveable about the middle line parallel to the long sides;.
A

page_text: I place it with the long straight side of the skein of wire in the magnetic
field. I effect this by stopping the two poles of the signal magnet at
such a distance from one another that two sides of the coil or skein can
be introduced between them instead of one side only. I place inside
the coil or skein a fixed soft iron core. The space between the iron
core and the magnet is as narrow as is consistent with freedom of
oscillation for the coil. By this arrangement I obtain the following
advantages-The force with which the coil is deflected by any given
current is increased, because it is now only the short portions of the
coil at the top and bottom that are not effectively influenced by the
electro-magnetic force. The length of the top and bottom portions of
the coil can by the new arrangement be greatly reduced, and so the
mass and moment of inertia much diminished. A better form of
suspension can also be applied to the coil as now improved.
To save the expense of maintaining an electric current constantly
through the coil of an electro-magnet with a soft iron core I make the
signal magnet a retentive electro-magnet according to the following
plan-The core is either altogether of steel or in part of steel, and it
is wound round with a coil ready to magnetize it powerfully in the
beginning, and to restore the magnetism at any time afterwards in case
of its having become too weak, whether through rough usage in
travelling, or change of climate, or lapse of time. I also provide (§ 44)
à suitable battery to give for an instant occasionally great magnetizing
power.
2. My next improvement consists in peculiar arrangements for
applying electro-magnetic induction to diminish injurious oscillations:
This effect, which I will call damping, is obtained by taking advantage
of induction between the moving coil and the magnet. It is well known
that a piece of copper or other conducting material moving in the
neighbourhood of a magnet experiences a resistance due to currents
induced in its mass. This effect becomes very sensible in the coil
arranged as described above if shunted and tends to check its motion
somewhat as does an air vane, but much more effectively. This
inductive damping may easily be pushed so far that after a sudden
change of position the coil shall come to rest in its new position without
oscillations, which enables the coil more truly to follow very sudden
changes in the received current, such as are experienced in ordinary land
telegraphs.

page_text: One method of producing the effect was described in my former
Specification, No. 2147 of 1867. It consists in applying a shunt to the
receiving coil. I now provide a set of shunt coils of graduated resistances
with a convenient arrangement, whether by a plug or slide, for applying
the desired degree of shunt to the moveable coil. By this means the
exact amount of damping suitable to each speed of signal can be ob-
tained. This system of graduated shunts is also convenient for assisting
in the adjustment of the sensibility of the instrument; but in many
cases it is better to confine the use of the shunts chiefly to the adjust-
ment of the damping effect, and to adjust the range of signals by
regulating the battery power employed, or by varying the directive
agency given by the suspension of the coil.
Another method is to construct the coil of fine bare wire, the ordinary
silk covering being wholly omitted. The effect of this is to partially
short circuit the coil by contact between successive layers; this partial
short circuiting produces the peculiar inductive action desired, and the
absence of the silk diminishes the mass of the coil, which is a subsidiary
advantage. If the coil is short circuited to an inconveniently great
degree by the use of bare wire, so as to diminish unduly the sensibility.
of the instrument to receive currents, part or the whole of the coil may
be very slightly silk covered, or otherwise coated with a thin layer of
matter of low conductivity, so as to leave some degree of short circuiting,
but not too much..
3. My next improvement consists in attaching the soft iron core
with the attachment of the wires, cords, or fibres bearing the moving
coil, and the syphon to a single supporting plate screwed to a stout
metal plate rigidly connected with the great magnet. This support
can readily be removed for the examination, adjustment, or repair of
any of the delicate parts. This support with soft iron core, suspended
coil,. connecting fibre, and suspended syphon, all mounted, it may be
kept ready in duplicate to replace almost instantly that which has been
in use in case of the syphon clogging or other accident.
4. My next improvement consists in adopting for suspension of the
moveable coil the double bifilar suspension described in my Specification
No. 329, 1858 (fourth part). I have added to the suspension, as there
described, an adjustment by which the tension of each fibre can be
separately increased or diminished. Each fibre is attached to a small
drum borne by pivots attached to a spring, so that the required tensión
A 2

page_text: .
is obtained by easy adjustments, and maintained with sufficient con-
stancy in the use of the instrument. I have also added a method of
increasing or diminishing at will the distance between the fibres at the
· point of support.
5. My next improvement also relates to the suspension of the moveable"
coil. It is more particularly useful for cases such as applications to
signals received through long submarine cables, in which extremely
rapid directive agency is not required. It consists in giving a directive
power by the tortional elasticity of two tightly stretched wires, by means
of which the moveable coil is pulled in opposite directions and sup-
ported. The wires serve also as electrodes between fixed terminals and
the ends of the moveable coil. Appliances are introduced to allow one
or both of these wires to be shortened or turned round the axis of the
coil's motion, so as to adjust the directive force and the undiflected
position of the coil to the fixed or varying requirements of any case.
Particular appliances by which I find it convenient to attain this object
are as follows:- One of the stretched torsion wires is wound round a small
drum or pully whose bearings are attached to a sliding piece capable of
being unclamped, moved parallel to the line of the axis of the moveable
coil's motion, and clamped again. By turning round the drum in one
direction or the other, and leaving it clamped or held fast by friction,
the part of the wire submitted to torsion is adjusted to the length
suitable for the degree of directive force required. The other torsion
wire is kept tight by a spring attached to a shaft moveable round an
axis, which is by proper mechanism adjusted accurately to be in line
with the axis of the coil's motion. This second torsion wire is made
strong enough to be capable of balancing by its torsional elasticity
'the greatest deflecting couple due to earth currents or other disturbing
causes which may have to be held in check in the use of the instrument.
6. My next improvement consists in supporting the syphon on a fine
wire tightly stretched by springs pulling its ends in opposite directions
instead of the torsional arrangement described in my Specification of
1867, No 2147.
7. My next improvement consists in tightening the fibre which
connects the syphon with the coil by applying couples to the coil and to
the syphon, tending to separate the points of attachment of the two ends
of the fibre. The use of torsional elasticity described in my fifth
A

page_text: improvement for directing the coil allows the couple required on it
for the purpose to be applied to it with great facility. Similarly the.
couple on the syphon is applied by turning one or other of the springs.
which stretch the bearing wire round a pivot coaxial or approximately
coaxial with the axis of the syphon's motion, but the desired couple.
may also be applied by aid of the milled head indicated in the diagram,
Figure 4 of the Drawings attached to my former Specification referred to.
above.
· 8. My next improvement consists in better constructive details by
which the marking tube (§ 9) or syphon ink bottle and connecting.
fibre can be more readily removed and replaced, which will be fully
explained by reference to the Drawings accompanying the Complete.
Specification.
9. My next improvement consists in substituting for the syphon a
fine tube fixed by an ink-tight fitting into the ink bottle, but having its
outer end sufficiently moveable to mark the signals, and applying by any
convenient hydrostatic method the proper fluid pressure to the liquid in
the ink vessel to give good marking with or without the electric action
or the vibrations described in my former Specification. One way of
fitting the tube for this purpose is by having a small portion of the ink
vessel where it is perforated by the tube of flexible or elastic material,
as, for instance, thin sheet india-rubber. Another method is to cement
the tube rigidly into the aperture of the ink bottle and trust to the
flexibility of the tube to give the requisite degree of mobility to its outer.`
end. If the whole tube is not firm enough for this purpose a portion of.
it near the ink vessel is made so, and thus an elastic joint is constituted.
If in any case the mobility in the plane of the paper is found too free.
with a round tube greater rigidity in this plane may be given either by a
stretched fibre or fibres acting on the same principle as stays in the
rigging of a ship, or by making the tube of oval section. A single stay
answers very well for this purpose. While giving greater effective.
rigidity in the plane perpendicular to the paper it will give either.
unchanged mobility or less mobility or greater mobility parallel to the
paper, according as its fixed end is in a certain line perpendicular to
the length of the tube or nearer the outer end or further from the outer
end. When the single stay is used I introduce a simple mechanism
by which the position of its fixed end is adjusted to give the desired
mobility to the outer end of the tube and the proper tightness of the stay.

page_text: The chief advantage of this improvement is that it allows the tenth
and eleventh improvements described below to be introduced. A
subsidiary advantage consists in allowing the plane of the arc along
which the marking end moves in virtue of the signals to be horizontal
instead of vertical, as it necessarily is with the syphon if of simplest
form and smallest moment of inertia attainable. The present improve-
ment allows when desired the signals to be first shewn on the portion of
the paper where it is running horizontally.
10. My next improvement consists of plans for urging liquid through
the marking tube by hydrostatic pressure. In many cases the requisite
pressure for good marking is that due to a few inches head of the liquid.
In all such cases this pressure is most conveniently obtained by having
free communication of air pressure between the atmosphere and the free
surface of ink in the ink vessel, that is to say, by having the ink vessel
either open or closed by a cover not perfectly air-tight. When a greater
constant pressure is desired than can be easily thus obtained I use my
ninth improvement and produce the requisite pressure either by gravity
acting on a column of mercury or by air or other fluid pressing on the
free surface of the ink, or by a piston, or by a flexible part of the ink
bottle acted on by force properly applied from without. The column of
mercury is preferable in respect of constancy.
11. My next improvement consists of plans for applying hydrostatic
pressure to free the tube from obstructions. If the tube becomes clogged
at any time so as to impair the marking the obstruction is often remove-
able by fluid pressure forcing the ink to flow through it. This cannot be
done easily for the syphon otherwise than by the operator's sucking the
lower end of it by his mouth, a delicate operation, involving considerable
danger to the syphon. My ninth improvement affords various methods
by which it may be done with much greater force with perfect safety to
the tube and without any dexterity on the part of the operator. For
instance, one of these is as follows:-I apply an air syringe of small bore
to the upper part of the ink bottle, which if ordinarily open to the air is
to be closed for the occasion by a proper plug or stop-cock. Any degree
of air pressure required is then readily applied to the free surface of the
ink. Another method is by a reservoir of mercury connected by a
flexible tube to one branch of a U tube the upper portion of the other.
branch of which is in hydrostatic communication with the ink vessel
either through the liquid itself continued to the surface of the mercury.

page_text: or through a portion of air intervening. A much greater pressure than can
be obtained by blowing with the mouth can be easily obtained by raising
the reservoir of mercury at any time through the space of a few inches
or feet. The mercury reservoir may be left ordinarily in such a position
as to give the proper pressure for regular marking, but at any time (in case
of suspected clogging for instance) it may be instantly raised or lowered so
as to produce a largely increased or largely diminished pressure. It often
happens that an obstruction can be only partially removed by forcing
the ink through the tube, in such cases nitric acid or other powerful
solvent forced through generally clears the obstruction perfectly away in
a moment. This is most easily done by applying (with the aid of the
apparatus described in § 15) nitric acid to the marking end, and drawing
a very small quantity through either by a syringe acting as a drawing
air pump, or by a mercury vessel lowered several inches below the level
of the tube.
12. My next improvement consists in adopting my ninth improvement
but substituting torsional elasticity of a long fine glass tube for the flexural
elasticity of the elastic joint which I used in the 9th improvement
when first testing it. This 12th improvement is most readily executed
by keeping the part of the tube used for torsion tightly stretched by
means of stout silk thread or fibre, pulling one end of it while the other
is fixed to the ink bottle. The signalling arm may be of the same
guage of glass tube as the torsional part, and continuous with it, simply
bent by the glass blower to its proper transverse position. The tight-
ening fibre should be attached at one end by cement or otherwise to
the torsional part of the glass tube near the bend where the marking
arm begins. To keep it constantly stretched with a proper degree of
force I use a metal spring or the force of a weight acting on its other
end.
13. My next improvement consists in attaching rigidly to the
syphon or signalling arm a counterpoise, so that its centre of inertia
may lie in the axis round which it turns. It has two advantages,
(1), diminishing the tendency to irregular vibrations caused by tremors
transmitted through the framework, whether from the running gear or
from disturbances in the neighbourhood, such as are experienced when
the instrument is used in a crowded city, in a factory, or at sea; (2),
checking the disturbance of siguals produced by the greater motions of
the ship when the instrument is used at sea.
'

page_text: 14. My next improvement consists in a mechanism for readily at
any time increasing or diminishing the distance between the marking
end of the signalling arm and the paper to secure good marking, and
to admit the application of the vessel of water or other solvent to the
marking end of the syphon or tube as described in my eleventh
improvement.
15. My next improvement consists in proper mechanism and
appliances for readily substituting a vessel of water or nitric acid or
other suitable solvent in place of the ink bottle, and for applying to
the marking end a vessel of such solvent, or a receptacle to receive ink
flowing when the instrument is out of use; by this means clogging not
removeable by hydrostatic pressure (§ 11) may be readily and speedily
dissolved away, and the instrument again set in action, and the marking
end may be kept under water or other suitable liquid to prevent the
ink from drying either in the tube or round the outside of it when the
instrument is not in use, and when it is not convenient to stop the flow
of ink through the tube when not in use, the ink which flows is con-
veniently made away with by being discharged into a large enough
vessel of water or other suitable liquid: Part of the mechanism consists
of a geometrical slide by which without any unclamping and clamping
and without disturbing the connecting fibre and suspended coil the
syphon may be raised out of the ink bottle, left to itself till the vessel
of solvent is put in position to receive either end of the syphon, and
lowered again. The motion of the frame bearing the syphon is to be in
a circle having for a centre the point of attachment of connecting fibre
to suspended coil. By "geometrical slide" I mean a slide fulfilling
the geometrical conditions described for the sliding one of the four
quadrants of my quadrant electrometer in the description of that
instrument published in the British Association Report for 1868, but
in the present case by cutting the V grove along a circular arc I have
made for the first time a geometrical slide giving circular motion.
16. My next improvement consists in applying oil, or paraffin, or
grease, or varnish, or other suitable coating round the outside of the
syphon or tube near its marking end to prevent the ink from spreading
by cohesion from that end along the outer surface, and so impairing the
delicacy of the marking.
17. My next improvement consists in giving a slow motion to the
paper driving gear readily substituted for the quick motion used for

page_text: recording, so that when no signals are being recorded the paper may
continue to move slowly past the marking end so as to carry away
the ink spurted continuously from the tube by the electric discharges.
This arrangement tends to prevent the clogging of the tube without
unnecessary waste of the paper. The details of one method for executing
this improvement are described in § 35 below.
18. My next improvement consists in driving the paper and the
replenisher by an electro-magnetic engine instead of by a spring or
weight.
19. My next improvement consists in constructing this electro-magnetic
engine so that soft iron armatures placed on the wheel, and attracted
one after another by an electro-magnet are parts of the carriers used
in the induction apparatus or "replenisher" employed to produce the
series of rapid electrical discharges spurting ink from the syphon.
20. My next improvement consists in details of great importance
regarding the make and break mechanism for the electro-magnetic
circuit of the engine including a method of adjusting the duration of
the current, and the times of making and breaking in respect to the
position of the soft iron armatures relatively to the electro-magnet. Tho
.contacts are broken by the action of a cam wheel upon a steel or agate
pin, and are made by return force of elasticity. This cam is of such
dimensions, the electric contact pieces are so placed, and the pin,
spring, and moveable contact piece are so constructed that a very gradual
slip in the lifting action of the cam, and a very small whole amount of
lift suffices to produce the break, and that the smallest sufficient mass
of matter is moved by the action, conditions all violated to the great
detriment of efficiency in all electro-magnetic engines of the same
The
general plan hitherto made or described so far as known to me.
moveable contact piece is a short piece of stout platinum wire soldered
near one end of an approximately straight steel spring. This end of the
spring is reduced to a round pin in line with the middle line of the
spring, and projecting to a short distance beyond the platinum contact
piece. The other end of the spring is attached to a fixed insulated
piece of metal with which it is in metallic communication, and through
5 which it forms part of the circuit which is completed when the moveable
contact piece is allowed to press on the fixed contact piece by the
projecting pin being freed by the cam. The line of the spring is parallel
to the axis of the electro-magnetic engine and its plane of motion passes

page_text: through this axis. The cam lifts the projecting pin to break contact,
and leaves it free at the proper times to make contact by its own elastic
force. The spring, which is approximately straight either when making
contact or when lifted through the small space of the cam's action on it
is under considerable elastic strain. When dismounted and allowed to
take its unstrained shape it is curved; in this state the curvature ought
if the flexual rigidity of the spring is uniform throughout to be
approximately in simple proportion to length along the curve from the
end which is fixed when the spring is in position. This condition is
casily fulfilled with sufficient approximation to accuracy by giving the
spring a proper set so that when mounted it is found to be nearly
enough straight, and to press with sufficient force against the fixed
contact piece to secure good contacts. The disposition described above
according to which the motion of the spring is in a plane perpendicular
to that of the cam, the form of the spring straight, and the point of
pressure of the cam very close to the moveable contact piece, secures
the great dynamical advantages stated above. The cam may work in
a vertical plane, and its lower edge dip in an oil vessel or press lightly
against a soft substance moistened with oil, or it is so arranged that
oil may with great ease be applied to its rim by the operator in charge
of the instrument. A steel screw acting on a jointed arm, which bears
the contact pieces is used to increase or diminish the distance between
these and the axis of the cam sufficiently to adjust the duration of the
contacts. Another simple mechanism allows the block carrying the
contact pieces and that first adjusting screw to be moved round an axis
nearly enough coincident with that of the engine shaft sufficiently
to adjust the time when the contact is made so as to obtain the best
action, or the cam itself is adjustable on the engine shaft. These details
will be fully described by reference to the Drawings which will accom-
pany the Complete Specification.
21. My next improvement consists in mechanical details regarding
the bearings of the electro-magnetic engine. The pivots of its main
shaft are of a peculiar form, which will be shewn in the Drawings; each
of these is supported on a single fixed roller, and is prevented from
slipping or rolling off this roller by two smooth parallel guides, between
which it plays easily. Motion of the shaft in the direction of its axis is
checked by two hard plates fixed perpendicular to its axis at a distance
asunder slightly greater than its length. The friction rollers, cach of

page_text: one piece of steel, are also of peculiar shape, which will be shewn in
the Drawings; they are kept in position by end plates, as described
above for the main shaft; each of them dips in an oil vessel, and carries
oil round sufficiently to keep its own pivots and the pivots of the main
shaft constantly oiled. The guiding cheeks of the main shaft and the
bearings of the friction rollers are so placed (as will be shewn in the
Drawings) that during the action of the instrument the pivots of
the main shaft press each of them only on one of those guides and on
the friction roller, but with much more force on the friction roller than
on the guide. It need press with no more force on the guide than to
prevent it from leaving that guide and moving over to the other under
the influence of the varying force to which it is subjected through the
successive electro-magnetic attractions.
22. My next improvement consists in a hanging shaft for transmitting
motion and reducing the speed from the engine to the paper driving
shaft. A smooth V grooved pulley borne by the main shaft of the
engine, or simply a groove cut in this shaft, drives an endless cord on
which hangs a large pulley below. This pulley is attached to a long
shaft, and carries a smaller pulley at a considerable distance from it;
this smaller pulley is hung on a V grooved pulley attached to the paper
shaft; the portions of the whole weight thus hung on the two cords.
must be each enough, but should not be more than enough, to secure the
requisite driving forces of friction; this condition I fulfil by fixing to
the hanging shaft in the proper position a weight of proper amount.
To give the requisite steadiness to the hanging shaft pivots of the form
to be shewn in the Drawings, being similar to those of the pivots of the
main shaft, are guided each by one vertical guide, and checked each by.
an end plate; or only one of them is checked by an end plate, which is
so placed as to press it slightly, but constantly. The vertical guides are
so placed that when the machine is not running they are just touched
and pressed with very little force by the pivots. The sides of the pivots
touched by the guides should be so chosen that if the paper shaft is
turned in the proper direction by force applied to it, and the engine
shaft thus compelled to move round, the pivots of the hanging shaft
shall jump off from the guides. Thus it is secured that when the-engine
drives the whole mechanism the pivots of the hanging shaft shall be
pressed gently against their guides with greater or less force according
as greater or less-resistance is opposed by the paper shaft. ;

page_text: '
This next improvement, besides rendering the loss of energy by
friction very small, has the great subsidiary advantage of affording
means for the engine to do work on the paper shaft without transmitting
mechanical vibrations to an inconveniently great degree, or to so great
a degree as would be done by any of the mechanisms commonly known
in the engineering of large or small machines. The cords should be
very flexible, and as the wear and tear is greatly diminished by my
present improvement, they may be simply stout silk cords, each with
its ends tied by an ordinary reefing knot. If either cord is crossed it is
prevented from rubbing against itself by arranging that the hanging
shaft is not parallel to the other shaft concerned, but deviates from it
somewhat in azimuth.
23. My next improvement consists of two parts. (1.) A means for
regulating the speed and diminishing the injurious spark at the break
of the electro-magnetic engine. (2.) A means of augmenting the
maximum speed attainable with a given battery, and of attaining
better economy of the electro-magnetic work.
(1.) I regulate the speed by graduated resistance coils, arranged to be
applied very readily to the coil of the driving electro-magnets, either as
shunts or as added resistances, and taken off, so as to produce the desired
adjustment. I keep on a weak permanent shunt to diminish the spark.
This and the regulating shunts are for the same purpose each made of
wire doubled on itself through its whole length, taking advantage of a
principle discovered by Faraday in the commencement of his experi-
mental researches in electricity.
24. (2.) I diminish the inductive action tending to produce the spark,
and increase the maximum speed and the efficiency by taking advantage
of another principle discovered by Faraday, and dividing the soft iron.
core into parts separated from one another by thin layers of varnish or
other non-conductor, in surfaces cutting across the lines of flow of the
currents which are induced in the iron when this improvement is not
made. One way of executing this improvement is to make the core
altogether or in part of varnished soft iron wire, which, however, has
the disadvantage of leaving considerable interstices not occupied by
iron. I prefer a smaller number of pieces fitting approximately to one
another.
23. My next improvement consists in regulating the speed of the
naner chaft with chronometric accuracy and I all

page_text: mark time accurately on the paper itself and to shew time as is done
by the hands of a clock. A shaft supported on friction rollers is placed
in prolongation of the paper driving shaft and is carried round by the
latter by means of a pin working in a radial slot so as to be easily
removeable and to be when at work not liable to lock or jam even
if its axis is not rigourously in line with that of the paper shaft. It
will be called for brevity the chronometer shaft. It rests on two
friction rollers attached to one long shaft (which may be supported on
ordinary bearings) below it. It bears upon these rollers by two other
rollers coaxial with itself. One of these other rollers is rigidly attached
to the chronometer shaft. The other is attached to a tube mounted
on this shaft by means of a collar at one end of the tube and a bearing
at its other end for one terminal pivot of the chronometer shaft. The
four rollers are of such dimensions as to give the tube such a differential
motion that it goes round somewhat faster than the chronometer shaft.
I find that something from five to ten per cent. faster than the chrono-
meter shaft gives good results. A second tube fitting by a collar at
each end of the chronometer shaft is placed close to the first mentioned
tube, and is carried round by a spring clip pressing it externally or by
other suitable friction gear. This second tube when unchecked is.
carried round as if rigidly connected with the first tube, but it can be
checked with ease so as to be altogether stopped at any time. When
it is released the friction is sufficient to set it very suddenly in motion
again with the same speed as the first tube. The second tube carries
one or more arms which act upon a pendulum through a pallet or
pallets after the manner of the teeth of a dead beat escapement wheel.
They keep the pendulum vibrating, and at each impact on the dead face
of the pallet the rotation of the tube is checked sufficiently to prevent
more than one arm from passing for every period of the pendulum:
Thus if a half seconds" pendulum be used, that is to say, a pendulum
whose period is one second, and if the second tube is to turn once
round in twenty seconds, there must be twenty arms.
These arms
might be rigid like the teeth of an ordinary escapement wheel so that
the arrangement would simply be an escapement wheel loose on the
chronometer shaft and influencing it in the manner described below.
But I prefer making the arms elastic to prevent damage in case of any
of them being taken aback by the pallet and also to regulate the motive
force applied to the pendulum by each arm in escaping the pallet.
There may be either two pallets arranged just like those of the ordinary

page_text: anchor of the dead beat escapement, or there may be only one pallet,
one side of the anchor as it were being cut away. When only one
pallet is used the plane of motion of the arm may very conveniently be
perpendicular to the plane of motion of the pendulum which gives an
arrangement preferable in point of simplicity to other more common
or obvious transformations of the general plan described above. A
spring carried round by the escapement wheel is kept in metallic
communication through a metal ring or disc, or cylinder, or grooved
pulley rigidly attached to the first or second tube and a spring pressing
upon it with a fixed wire. Another fixed wire is similarly kept in com-
munication with a metal ring rigidly attached to the chronometer shaft,
a rim composed partly of metal connected with this ring and partly of
insulating material rigidly attached to the chronometer shaft is touched
by the spring carried by the escapement wheel. By insulating materials
properly placed these two wires are cut off from metallic communi-
cation through the moving parts which have been described except
when the elastic arm carried by the escapement wheel is in contact
with the metallic part of the rim on which it presses. One or other of
them may be in metallic communication with the chronometer shaft and
the two tubes; but I prefer insulating all the pieces of metal which
are in connection with either of the fixed wires by vulcanite or other
proper material so as to prevent metallic communication between them
and the shaft and tubes. The two fixed wires are connected to the two
ends of the coil of the driving electro-magnet by electrodes of proper
resistance to fulfil the following condition :-When the second tube is
in such a position relatively to the main shaft as to make contact the
coil of the electro-magnet is shunted so as to reduce the driving power
sufficiently for the purpose of regulation. For example if the resistance
in the electrodes and moveable contact pieces which have been described
are infinitely small the driving power would be altogether stopped when
the contact referred to is made; but this would be a more abrupt con-
trolling action than is desirable. In most cases I prefer to arrange so
that the resistance in the shunt shall be several times greater than the
resistance in the electro-magnet, and I secure that the controlling action
shall be sufficient by adjusting the rate approximately by the method
described in (§. 23). All that is necessary to secure this condition is that
without the regulating shunt the chronometer shaft would attain a
speed greater than the proper speed, but that when the shunt is applied
the power is insufficient to maintain the proper speed.

page_text: 26. To shew minutes and hours and mark them on the I attach
.paper
à toothed wheel to the paper shaft or to the subsudiary shaft described
in § 35, and by it drive a train of shafts at the successive slower speeds
desired; thus the paper shaft going once round in a third of a minuté
the next shaft may go once round in five minutes, the next once round
in an hour, and the last once round in twenty-four hours. The five
minutes shaft shows time to the nearest second on a properly divided
disc either turning with the shaft or fixed. The hour shaft shows the
minute, and the twenty-four hour shaft the hour reckoned from 0 to 24,
astronomical reckoning. The train may be set to correct Greenwich
'time (telegraphed through the lines at sufficient intervals) by turning
round the paper shaft which is permitted with sufficient freedom by the
friction gearings described above. The twenty-four hours wheel carries
steel stamps at equal intervals to mark the figures from 0 to 24 on the
paper. A hammer whose upper acting surface is mounted with leather,
india-rubber, or other soft material is so mounted and so influenced by
a spring that it rests when undisturbed at a very short distance below
the rim to which these stamps are attached, but is movable downwards
or upwards. It is depressed gradually by a snail or pin carried round
by the one hour shaft, and is suddenly released exactly at the end of
each hour, when it flies up beyond its position of equilibrium and strikes
the paper against the hour stamp which is passing at the time. The
paper is so led before it reaches the drawing drum that it passes between
the hammer and the stamping rim, and so is always in position to
receive the impression of each stamp by the blow of the hammer. Or
the figures may be printed upon the paper in ink by a proper arrange-
ment for inking each type before it reaches the proper place. When
the plan described in § 36 is used the hours and half hours from 0 to 12
are marked on the paper. If desired the minutes, or every five minutes,
may be also stamped on the paper by types attached to the one hour
shaft and a hammer worked by the five minutes shaft. A short knife
edge projecting very slightly from one of the rims of the paper drawing
drum marks its revolutions on the paper and subdivision of the space
from mark to mark [which may correspond (§ 26) to twenty seconds
uniformly or (§ 36) to twenty seconds of receiving or five seconds of
sending] readily gives time to the nearest second.

page_text: -
to send messages through the line. By a proper punching apparatus
the messages to be sent are to be stamped upon the paper so as to give
Morse signals, or Steinheil signals, or signals of any other kind. Each
message or set of consecutive messages may be stamped on the ribbon
of paper continuous with that which is used in receiving signals from
the other end in such a position as to enter the wheelwork at the time
arranged for the remote station to commence receiving. But especially
for recommandé messages it may be desirable to stamp the message to
be sent on separate paper in order to give time and convenience for
thoroughly verifying before sending it. In such cases either a separate
machine may be used or the ordinary receiving paper may be cut and
the special message gummed to the part running into the wheelwork.
By this arrangement one continuous slip of paper delivered from the
wheelwork will contain the syphon records of all the received messages,
and (§ 28) all the sent messages and the perforations by which the sent
messages have been sent, and (§ 26) the impressions showing the hour,
minute, and second at which any part of any message passed the syphon
accurately marked in Greenwich time. Thus the paper delivered from
the instrument contains a permanent record of every signal which has
passed through the line in either direction in a form thoroughly con-.
venient for subsequent verification or comparison. The superintending
officer at the sending station can make certain that each message is
stamped on the sending paper with absolute accuracy, also by the
syphon record of the sent signals he can make sure that no failure in
the battery or electric contacts or connection with the line has vitiated
the transmission of the message and that each individual component
signal has been accurately delivered into the cable. Hence no repetition
even for recommandé messages or figures will be necessary unless some
failure of the record at the other end leaves doubt as to some of the
signals in the message there received.
28. To adapt the syphon recorder to write sent signals as well as
received signals on the continuous ribbon of paper I apply a powerful
shunt on the electrodes of the movable coil. A shunt whose conducting
power is from 20 to 50 times that of the suspended coil answers well in
most cases of long submarine signalling. To do this readily I add a
shunting contact to the switch used to alter the connections from
sending to receiving. To make sure of the several contacts thus
required in the switch I have made a switch of peculiarly simple con-

page_text: struction. It consists of contact studs and a stout bar of brass or other
suitable metal pivoted on a round steel rod passing through a hole about
its middle and fixed horizontally. The bar is pressed horizontally near
its middle by a strong spring on one side and is resisted by contact
One end is
pieces or vulcanite pressing its opposite side near its ends.
put down for sending, and up for receiving. In the first position each'
end makes a metallic contact; in the second position only one end does
SO. The cable is constantly in connection with the bar through the
central spring. The usual middle (or discharging) contact if desired for
any purpose is given by a stud, across which one end of the bar slips
in being switched up or down.
-
29. When the instrument is used for sending by aid of perforated
paper the paper may be drawn by the drum and roller merely in the
ordinary manner. To make the signals I use the following system of
contacts: The paper is drawn firmly over a fixed smooth surface, and
one, two, or more springs press, upon the paper except when a hole
in it allows them to press upon that fixed surface. Insulated metal
studs carrying the proper clectrodes are fixed with their faces, flush
with that fixed surface, so that when apertures in the paper permit it'
contacts are made by the pressure of the springs on these studs. To
make single current signals as in the Morse system I use two springs,
one of which when in contact with its stud connects the line with the
earth, the other the line with the insulated pole of the battery.
30. Or I use only a single contact spring, and I keep the near end of
the line in connection with the earthed pole of the battery through a
wire of sufficient resistance, and the contact spring when in contact with
its stud connects the other pole of the battery with the line. If the
resistance of the battery is small in comparison with that of the wire
resistance just referred to, the fact of the line being constantly con-
nected with the carth through this wire resistance will not greatly
diminish the potential produced in the line by the battery from what it
would be were the resistance of the wire infinite.
31. Similarly when I wish to make Steinheil signals (such as those
hitherto used in long submarine cables according to my system) I.
employ three contact springs, which when their contacts are made
connect the cable respectively with the earth, or with the positive or
with the negative pole of a battery, the middle of this battery being
earthed.

page_text: 32. Or I use only two contact springs, and I keep the two poles of
the battery constantly connected with one another through a wire of
sufficient resistance, the middle of this wire being constantly connected
with the cable and the middle of the battery with the earth. This
method (§§ 30, 32,) besides its great simplicity has the advantage of
diminishing much the lost time experienced in passing from one to
another of the contacts made in more ordinary methods of telegraphic
signalling. It is particularly valuable also for the Steinheil signalling
by hand hitherto practised on long submarine cables, inasmuch as it
does away with the upper contacts, which in the ordinary keys have been
found liable to fail, and gives more regular and more sharp signalling.
33. When I use signals produced by applying to the near end
electrifications of several different degrees of potential (as specified in
my Patent of 1858, No. 329), I use either of the methods just described,
but I prefer the latter (§§ 30, 32,) according to which the two poles
of the battery are kept connected by a wire of sufficient resistance.
Electrodes lead from several points of this wire to the contact springs or
studs, the studs or springs being kept connected with the cable, and one
point of the battery, generally its middle, is kept connected with the
earth. Perforations in the paper along any one, two, or more lines parallel
to its length allow contacts to be made with regularity for the Morse,
Steinheil, or other system used. Sometimes instead of drawing the
paper in the manner described in (§ 29) it may be desired to draw it more
definitely, so that each single perforation shall pass the contact piece at
an instant when the wheelwork has a definite. position. When this is
desired I arrange as follows:-The paper drum is definitely geared by
toothed wheels to turn with the same tangential velocity as a roller of
diameter equal to its own or half its own, or conveniently commensurable
with its own. The paper passes between the drum and this roller, but
is not pressed firmly between them; it is drawn by teeth in one of
them projecting into hollows of the other. When it is desired to record
the sent signals of the syphon on the perforated paper itself which is
used for sending, and to have the same drum and roller arranged to draw
the paper when the instrument is used for receiving the perforations by
which the paper is drawn may conveniently be made in two rows very
near its two edges. The drawing teeth and hollows must lie on corre-
sponding circles of the drum and roller. The receiving paper may be
prepared with perforations, so that it shall be drawn through the instru-

page_text: ment by teeth just as is the paper used for sending. Paper prepared for
sending must have another row or two or more other rows of perforations
punched upon it in proper positions to produce the signals. These
positions must be made by the punching machine quite definitely in
relation to the perforations designed for the drawing teeth. Or if it is
desired to avoid the necessity of perforations in the paper used for
receiving, the roller used in sending having teeth projecting into hollows
in the main paper drum may be replaced by the ordinary roller pressed
firmly against the drum whenever the instrument is adjusted for
receiving instead of sending; or the same drum and roller may be used
provided the drawing teeth are of proper shapes and magnitudes not to
damage the paper nor impair the regularity with which it is drawn past
the syphon. The same wheelwork can be used for a curb key to be
worked by hand; thus a disc on the same shaft as the paper drum is
notched in its circumference properly, and acts as a cam upon a spring
contact piece or pieces.
A hand key (double for the Steinheil system) is used to prepare for
the contacts. When either finger piece is pressed down it does not
instantly make its contact, but presses a spring ready to make it as soon
as the cam permits the contact piece to fall. The operator perceives by
car, or touch, or both, when the contact is made, and holds on his finger
till he perceives the cam to have unmade it again; or else a simple
mechanism holds on the contact when once made until the proper instant
for terminating it. One plan for this mechanism is to have the cam cut
with a circular groove, into which a pin enters when permitted by the
notch, and which holds the pin down until a second notch allows it to
rise. But many other mechanisms can readily be devised according to
the dimensions and speeds convenient in the actual instrument and its
particular application.
35. To draw the paper at the quicker rate proper for sending (when
the rate found convenient and economical of paper in receiving does not
suffice for sending) I make the drawing wheel or drum movable freely
relatively to its own shaft round their common axis. By a ratchet wheel
and pawl it is prevented from running backwards relatively to the
shaft, but it is free to move forwards. The ratchet wheel may be either
very fine, or it may be infinitely fine with the pawl pressing on it at an
angle less than the sliding angle, so that when the drum is running round
faster than the shaft there may be no disagreeable noise. By toothed
□ 2.

page_text: rately in proper positions; (3), a punching key or punching keys to make
the perforations which give the signals.
38. When the simple plan of (§ 29, 33) is used the two rollers may
draw the paper in the usual way, but if so they must be pressed very
firmly on the two sides of the paper, so that the portion of it in the place
where the punching is performed may start and stop instantly with the
rollers. To secure this condition I apply sufficient frictional or tan-
gential resistance to the paper before it reaches the rollers to draw it
tightly over the place where the punch acts.
39. When the paper is to serve for the system of (§ 34) the rollers.
still forcibly pressed together are provided respectively with teeth and.
with hollows very slightly larger than the teeth to cut the perforations
by which the paper is drawn (§ 34) through the sending machine.
40. The mechanism for moving the rollers is either on the same
general plan as the lever windlasses so commonly used in ships, or it
may be on the principle of the dead beat escapement, but in this case
there must be motive power acting (as on the escapement wheel), so
that the rollers always tend forwards. For stopping the rollers exactly.
in the proper position every time before the punch acts I use either a
sustained resisting force or a sustained forward force to maintain steady
pressure against a pawl or other stop, and steady pressure between the
teeth of the gearing concerned in holding them. When this is done by
a sustained resisting force elasticity or gravity must be used to draw the
paper back by the force (§ 38) used to keep it tight. A key moved to
and fro by hand acts on the mechanism, so as by each motion to and fro
to carry the paper forward through a definite space without causing it to
be perforated. This key I shall for brevity call the space key.
41. I perform the punching by a lever acting on a properly shaped
die. When greater accuracy is desired for the dimensions of the aperture'
than can be otherwise obtained I add a movable guard round the die
according to the following description:-A piece of metal leaving an
aperture of the proper shape and dimensions is pressed down on the
paper immediately before the die reaches the paper. The die fitting like
a piston in this aperture is pressed through this aperture against the
paper, and into another aperture in a fixed piece of metal on the far side
of the paper, fitting as closely to the die and forming as exactly a
prolongation of the first aperture as good workmanship can make it to
fit without giving rise to the great resistance by the motion of the dic.

page_text: ..
Thus just before the die acts the paper is held firmly between two solids
close round the piece of it that is to be cut out by the die. The die
returns through the perforation before the paper is released. To obviate
difficulty in detaching the fragment of paper cut out by the die I some-
times make the die hollow with a rod sliding through the hollow space
which it nearly fills; this rod after the die has made its cut protudes
and presses away the fragment of paper. A single pressing surface
acting on properly arranged springs produces these three motions,
and its return allows the inner rod, the die, and the guard to return
in order. The return of the lever which acts on the die gives the
rollers the motion or permits them to take the motion required to
place the paper in the position for the next action of the die. When
as for the Steinheil system of signals or higher multiple systems (such
as those described in my 1858 Specification, No. 329) two or more
dies are required, I use a separate lever for each dio, and arrange
that the depression of any one alone of these levers draws down one
common lever or moves one proper piece of mechanism, the return of
which moves the paper into the proper position for the next perforation.
For very rapid action the tendency of the rollers and paper to run too
far
may be not completely checked by the arrangement described above,
but it secures that they are drawn back into correct position before the
punch acts, but the forces concerned are necessarily large. Hence very
strong material must be used for the different moving parts, but the
massiveness required to give the necessary strength itself involves the
action of much larger forces than are necessary merely for the operation
of punching the paper, I therefore prefer an altogether different plan of
instrument for rapid action, and have therefore invented the following:—
To avoid circumlocutions I shall suppose the Steinheil system of signal-
ling to be adopted, and the signalling perforations to be in two rows,
and further I shall either suppose that there are no other perforations
than those in the two rows, and that the paper is drawn along both in
the punching instrument and also afterwards in the automatic sender
merely by the pressure of a drum with milled rims, or I shall suppose
a row or rows of perforations at equal intervals to be made in the
paper for the purpose of drawing it through in the automatic sender as
herein-before described. The same plan with obvious enough changes of
detail is applicable to perforate the paper for other modes of signalling
which may be desired in any case. I use three levers which according to
usage will often be called keys. One of them I shall call the space key

page_text: .
another the dot key, and another the dash key, the recent submarine usage
having applied the name of dots and dashes in submarine signalling to
left and right motions of the marker. When any one of the three keys
is depressed and allowed to rise it causes a certain shaft which I shall
call the revolver to turn through a certain angle either a complete turu
or any sub-multiple of a turn. I shall describe the details on the
supposition that it is a complete turn. This shaft during a definite part
of the revolution acts on the paper drum, so as to cause it to commence
gradually moving, and after having attained a maximum velocity to
gradually cease moving when it has reached a perfectly definite position.
This effect is produced by a pin carried round by the revolver so as to
enter a radial slot in a disk coaxial with the paper drum moving radially
when it enters and leaves the slot. To make sure that the paper drum does
not move except through the action of the revolver a clutch checking it
in exactly the proper position may be appended. Further this clutch.
may be so arranged that if through want of absolute truth in the
mechanism the position in which the paper drum is left by the pin be not
precisely correct, the drum may be brought forward or backward so as
to bring the paper to its precisely correct position ready for the punch.
Lastly, to make sure of the very definite action of this clutch it is
desirable that the surfaces of the V notch on which it acts should be
inclined at an angle smaller than a right angle, or at most not much
greater than a right angle. To get the best result I therefore add an
application by which the clutch is lifted through the action of the key
shortly before the instant when the pin of the revolver enters the radial
slot. But a good result may be obtained more simply by inclining the
faces of the V differently to the radius through their intersection, and
arranging the line of motion of the clutch so that it cannot jam either
when it is pressing the wheel back, or when the wheel by moving forward
lifts it. The mode in which each key acts on the revolver may be as
follows: The key being supposed to, be approximately horizontal and
the motion of each acting part approximately vertical. When the key
is pressed down it presses upon a treadle as it were, which like that. of a
lathe works on the revolver shaft through something less than half of its
5 revolution, which is continued and completed through inertia. The
clutch dropping into the V notch stops the revolver shaft sharply enough
in its proper position for the next action of any of the keys. The notch
may be sufficiently obtuse to allow the clutch. to. be lifted as by a cam
by one side of the V when a fresh action of one of the keys turns the
"

page_text: revolver. The inertia by which a complete revolution of the revolver in a
sufficiently short time is secured is that of a fly wheel loose on the revolver
shaft but acting on it through friction. This friction is best produced by
a cord having its two ends attached to arms on the fly wheel and itself
wrapped more than once round the revolver shaft. The arm to which
the after end of the cord is attached is rigid, the other is a spring
tightening the fore end of the string with a force approximately equal to
the tangential force required when the fly wheel draws the revolver after
it. This arrangement causes when motive power is applied to the shaft a
much greater force than that of the spring to act on the rigid arm and
accelerate the fly wheel. Any one of the three keys pressed down alone
acts through the treadle in the manner described above upon the revolver.
The space key does nothing else. Each of the other keys in being
depressed punches the paper and rises by force either of a stout spring or
of the treadle or of both, the dot key makes its perforations in the proper
line of the dots, the dash key in that for the dashes. The punches may
be rigidly attached to the keys, or they may move in geometrical slides
pressed down to cut the paper by the key and returning by springs. I
prefer to connect each punch rigidly with its key. The pin on the
revolver which drives the paper shaft is so placed relatively to the 1
crank pin by which the treadle gives motion to the revolver that the
vaper is at rest for the whole time during which the lowest part of any of
the punches is below the upper surface of the paper, it being supposed
that the punches move downwards in cutting.
42. The interval which distinguishes the beginning of a new letter, 2
number, or other signal from the beginning of an additional constituent
signal of an incomplete compound letter or signal will be called for
brevity the letter space. Similarly I shall call the word space the
excess above the letter space which is used to distinguish the com-
mencement of a new word or group from the continuation of an unfinished a
word or group. It is generally convenient to make the word space
equal to the letter space. To save time in sending a message I sometimes
make the letter space shorter than the interval between the consecutive
individual component signals of which compound letters, or signals,
or numbers are compounded. For example, I make the letter space
half that. of the component signals, and to do so I arrange that the
space they (§ 40) shall move the paper through just half the space
that it is moved through by the return action described in (§ 41) when
this system is followed punctuation may be sent in such a manner as

page_text: to promote clearness very much with but very little loss of time.
Thus a comma may be given by adding a space equal to the latter space,
to the word space, a semicolon by adding the same to the comma,
and so on.
When a semicolon, or colon, or full stop, or mark for a
new paragraph is sent as a definite signal and not merely to promote
clearness in the reading of a messuage the comparatively elaborate groups
of signals prescribed for them in existing codes may still be used. Or
the comma space may be made double the letter space or word space,
the addition to the comma space for the semicolon equal to the comma
space, the addition to the semicolon space for the colon equal to double
the comma space, and the addition to the colon for the full stop equal to
double the comma space. This with the accuracy of spacing produced by
automatic sending with accurately executed perforations and with the
syphon record of received signals will give thoroughly distinct indications
to distinguish precisely which of the stops is meant, and will still be
considerably shorter than the signalling of the stops practised at present
on long submarine lines according to the Vienna code, with lefts and
rights substituted for dots and dashes. But when the curb key method
by perforated paper and a cam as described in (§ 34) is adopted the
letter space cannot readily be made less than the interval of the com-
ponent simple signals, and the greatest economy of time attainable
without mechanical complications is had by making the letter space
equal to that interval. In preparing the paper by perforations to send
a message the letter space is produced by a single pressure and return
the word space by a second pressure and return of the space key.
43. Each separate rigid solid in the punching machine should have
just one degree of freedom to move. I arrange for this in each case
by five perfectly different degrees of constraint planned on geometrical
and dynamical principles (1) to maintain each degree of constraint with
sufficient force to meet the greatest tendency to break it which can
occur in the use of the instrument; (2) to oppose rigidity enough against
the inevitable elastic deviations from the geometrical conditions; (3) to
produce no inconveniently great amount of frictional resistance against
the motions provided for. For example, cach lever is pivotted on
definite V bearings according to the principle used in a transit instru-
ment, and each piece to slide to and fro in a straight line is guided
by a "geometrical slide" ( § 15). The details of construction by which
these conditions are realized, differ greatly from those of any other

page_text: telegraph instruments or ordinary mechanism known to me. They will
be fully described with aid of Drawings in the Complete Specification.
44. It is important to have a battery of small resistance which shall
be very constant in its action and require renewal but rarely to drive
the electro-magnetic engine, to sustain the signal magnet (except when
it is a permanent magnet), and to perform the electric work of the
rending especially if performed according to the general method of
(§§ 30, 33). For these and for general telegraphic purposes I have
made improvements on the form of battery described in Thomson and
Jenkins' Patent 1860, No. 2047, and commonly known as the "sawdust
Daniells" or the tray battery. I use trays of copper or lead or other
suitable metal to contain the sulphate of copper, the liquid, and the
sawdust or other porous material. I add false bottoms of thin sheet
copper or other metal to facilitate the removal of the deposited copper,
and the realizing of its metallic value. I apply a coating of paint or
varnish or other non-conducting material to prevent the deposition of
copper on the tray itself. I solder properly placed contact pieces of
metal to the bottoms of the trays outside, I add a wooden frame inside
each tray to bear the weight of the zinc and of the superincumbent
column when the battery is filled one cell above another. This frame
serves also to confine the sawdust or other porous material in a proper
place by the clear space which it leaves round itself, and allows the
addition of more sulphate of copper in solid fragments and of water
to replenish for loss by evaporation, I cast the zino to be used in the
form of flat slabs with ridges or other suitable projections on its upper
side to bear the tray next above when there is one, and to present surfaces
of zinc always dry, for the electric contacts. Instead of copper trays I
sometimes use wooden trays lined with lead; the sides of the wooden
trays are inclined, and the lead lining is not soldered but simply pressed
into shape. The lead holds water-tight, and the wood is of use mercly
to support the lead and give the stiffness requisite for convenient use.
A hole in the bottom of the wood with a copper electrode soldered to
the lead above protruding downwards is used to make the connection.
4
45. I also in some cases provide as a powerful battery for occasional
use to remagnetize the signal magnet one of the old forms of battery
with large surfaces of zinc and copper close together in dilute sulphuric
acid, the plates being let down into the liquid and lifted again as soon as

page_text: plates in the liquid for more than a few seconds on each occasion for
this purpose.
46. My next improvement in the ink spirting recorder consists in a
regulator for electrification of the syphon. When the electric machine
used is simply the replenisher described in my previous Specification or
that described above (§ 19) I have found irregularities and occasionally
temporary failures of the marking to proceede from dischargings of the
insulated inductor effected by intermittent connections between the ink
in the syphon and the paper with its metal backing. To prevent this I
connect the ink with the inductor by an electrode of very high resistance
readily adjustable at any time to the observed requirements. To promote
speedy clectrification of the right kind after any accidental discharge and
to secure electrification, positive or negative, whichever may be found to
give the better marking, I introduce a dry pile into the line of this.
electrode. In case of the electrification of the inductor being found so
high as to give too much electricity to the syphon I shunt off some of its
electricity by another electrode of great resistance (also adjustible to
different degrees) placed so as to connect directly the insulated conductor
to the uninsulated metal work of the instrument. To further promote the
rapid re-electrification of the insulated conductor with the right kind of
electrification I put another dry pile in the line of the second highly
resisting electrode resistance. A plan which I have found convenient for
these adjustable high resistances is a vulcanite cylinder with a deep spiral
groove cut in it. A silk or cotton thread attached to the metal shaft
bearing this cylinder passes through a hole or groove in the vulcanite to
one end of the spiral groove. The other end of this thread is attached to
a small metal drum acted on by a spring like that of an ordinary pocket
measuring tape. By turning the vulcanite drum the thread is wound
round it and pulled out from the metal drum so as to augment the
resistance as in Wheatstone's rheostat. When the vulcanite drum is
turned in the other direction the spring draws the string round the metal
drum and the resistance is diminished. If the smallest resistance thus
obtained when the two drums are conveniently placed is found to be too
small the part of the thread remaining unwound between the vulcanite
drum and the metal shaft of the vulcanite drum may be impregnated
with salt or it may be even replaced by fine metallic wire. If it is found
that positivo electrification of the syphon gives better marking than

page_text: negative electrification the positive end of each dry pile must be placed
towards and the negative end from the insulated conductor in the two
electrodes described above, or vice versa if negative electrification of the
syphon is desired.
47. My next improvement consists in placing all the resistance coils
used (whether as shunts or as added resistances) for regulating the electro-
magnetic engine or the signal magnet in such positions that the head
generated in them shall tend to dry the reuniting parts of the replenisher
and electrostatic system generally used to produce the writing by the
syphon. To promote this object and to guard against the settling of dust
and soot on surfaces electrified directly or indirectly from the action
of the replenisher as well as to guard against accidental mechanical
damage to the syphon, fibre, &c., and to keep the clockwork clean I
enclose all the moving parts and highly electrified parts in a case chiefly
of glass to allow the action to be readily seen and the signals to be read
if desired direct from the point of the syphon.
48. I also construct the syphon recorder with proper variations, such
as increasing greatly the number of turns in the suspended coil (and
farther if need be the power of the signal magnet) to render it adequate'
to supersede my marine galvernometer for testing cables at sea, with the
advantage of recording the test at every instant.
49. The moveable coil suspended in the magnetic field in the manner
described in (§§ 1, 4, 5,) may also be employed to make relay contacts in
cases in which a relay is used. I arrange to make these contacts by a
metallic contact either carried directly by the moveable coil or moved by
a lever or other proper mechanism worked by a fibre or connecting
link attached to the coil. I prefer a lever supported by a stretched wire.
on the same plan as the support of the syphon. The connecting fibre is
kept tight in the manner described in (§ 7). The bearing wire forms
part of one of the electrodes leading to the contact piece.
50. I will now proceed to describe further my improvements in
mechanism for drawing telegraphic receiving paper at a uniform rate,
together with other improvements in clocks generally. I arrange by
proper mechanism to produce independently of the pendulum an
approximately uniform motion of the whole train of wheelwork as approxi-
mately the proper rate with provisions for adjustment, by which precisely
the proper rate or any other rate within considerable limits on either
side the proper rate may be readily given at any time. By peculiar

page_text: mechanism I arrange that when the instrument is adjusted to any
speed within certain limits and left to itself it will of itself vary the
adjustment so as to augment its speed to something decidedly above
the proper speed. This automatic change of the adjustment may be
gradual or it may be simply from one grade to another, or it may
be from one grade to several other grades of higher and higher speeds.
Lastly, by a movement geometrically comparible with Graham's dead
beat escapement I arrange that a certain shaft or wheel turned by
the mechanism shall. keep a pendulum vibrating, and shall be pre-
vented by the pendulum from going round on the whole faster than
to allow one tooth or arm to pass during each period of the pendulum's
motion, this wheel or shaft having any number of teeth or arms
which correspond geometrically to the teeth of the ordinary escape-
ment wheel. One such tooth or arm suffices, and for some purposes
is preferable to any greater number. The tooth or arm may be rigid
and rigidly attached to the shaft or wheel, which for brevity I shall
call the escapement wheel, but I prefer to mako it elastic or to connect
it elastically with the escapement wheel to obviate damage in case
of its being accidentally taken aback by the pallets when the clock
is being set in motion or when it is imperfectly adjusted, and also
to regulate the amount of the working force with which it acts on
the pallet when in regular operation. When not touched by the pallet
the escapement wheel is carried by a differential motion at a rato
somewhat exceeding that of another shaft which I shall call the
chronometer shaft, and which I generally find it convenient to make
coaxial with the escapement wheel. But this differential motion
carries the escapement wheel only by force of friction, and at any
time the escapement wheel which may be stopped by the application
to it of a sufficient resistance to overcome this friction. The action
of the pendulum ensures the correct rate for the escapement wheel.
The adjustment described in general terms above acts so that when
the chronometer shaft runs at a speed lower than the average speed
of the escapement wheel the resistance is diminished or the moving
force is increased so as to augment the speed of the chronometer
shaft. But when on the contrary the chronometer shaft gains on the
escapement wheel the adjusting action adds resistance or diminishes
the moving force, and so diminishes the speed of the chronometer
shaft. Thus it is secured that the chronometer shaft shall have the
same average speed as the escapement wheel, but it moves without

page_text: stopping and at a very approximately uniform speed through the
whole period of the pendulum instead of being brought to rest once
or twice in the period of the pendulum's motion as is the escape-
ment wheel. The chronometer shaft is connected by toothed gearing
with a train of wheel work, by which motion is imparted to the
hands, discs, or counters required for marking time or for producing
any accurately uniform motion for which ordinary clockwork is some-
times used, as, for instance, moving an equatorial or drawing telegraphic
receiving paper at a uniform rate, or giving the uniform motion required
in sending upon any plan of automatic telegraph signals. When
weights are used to drive the clockwork one plan which I have
practised for the adjusting action described generally above is to
have a screw and nut each coaxial with the chronometer shaft and
escapement wheel, one of them rigidly connected with one of these
bodies, and the other carried round by the other through tangential
friction. When the nut turns in one direction relatively to the screw
its consequent motion. parallel to the axis augments the speed of the
chronometer shaft, and vice versa. And more particularly in these
cases I have made the axis of the chronometer shaft and escapement
wheel vertical, and arranged that the motion of the nut upwards or
downwards shall increase or diminish. the elastic force by which the
centrifugal pressure of whirling masses against a friction rim keeping
them from passing its circle is regulated to such a degree as to give
the frictional resistance required to maintain the proper speed. For
a clock driven by water power the frictional method just described may
be used, but I prefer to apply mechanism to diminish or augment the
water supply according as the chronometer shaft gains or loses on the
escapement wheel.
The
51. For a clock driven by electro-magnetism a friction governor may
be similarly used or the differential motion may be employed to diminish
or increase the driving power from one grade to another, or to several
others successively. The latter method I prefer, and among various
plans for carrying it out I have found the following very simple one,
which I have already referred to in (§ 24) to answer well.
escapement wheel and the chronometer shaft carry one of them a ring,
and the other a metallic spring touching the ring. The ring is partly of
insulating material and partly of metal insulated from the spring, except
when touched by it. The spring and the metallic part of the ring are
through complete metallic rings kept permenantly in connection with

page_text: two fixed conductors.
These conductors are connected with the wire of
the driving electro-magnet, either in such a manner that when the spring
makes contact with the metallic part of the first-mentioned ring a shunt
is applied to the electro-magnet and its power is diminished, or in such a
manner that when the spring touches the non-metallic part of the ring
the circuit of the electro-magnet is broken. The shunting method has
the advantage of being less abrupt in its control and also of diminishing
the destructive influence of heat at the places of making and breaking
of contacts, both in the engine and in the regulator, and to promote
this advantage I double úpon itself the wire used for shunt, in order to
diminish the quasi inertia of the electricity flowing through it. For the
same reason I sometimes apply to the electrodes of the driving battery
a constant shunt of wire doubled on itself.
52. I use an improved method or pattern of gear for making and
breaking contacts in the electro-magnetic engine,, which has great advan-
tages over the methods or patterns in ordinary use in respect to smallness
of the dynamic power required, accuracy of the times of make and break
relatively to the positions to the running part or parts of the engine,
durability of the parts liable to mechanical or electrical wear and tear,
and facility for replacing or repairing any part which inevitably wears
out. The details of this method or pattern, which cannot be well
described without the aid of Drawings, will be fully described and
explained in the Complete Specification Drawing. They are of great
importance in respect to the practical application of my present In-
vention. With them I have succeeded in obtaining power enough and
durability enough to drive a large tower clock by an electro-magnetic
engine of very moderate dimensions regulated by very small and simple
clockwork on the plan described above. A very moderate galvanic
battery suffices as the source of energy by which I thus replace weights.
53. When an electro-magnet with soft iron core with circuit made
and broken alternately is used for the driving power I make the soft
iron core altogether or in great part of thin iron wires varnished and
pressed close together to obviate the slowness of magnetization and
demagnetization and the loss of energy due to electric currents in the
iron..
54. For very accurate time keeping I have designed (for use in
connection with the preceding or any other plan of escapement) a
pendulum with compensation for changes of temperature comparatively

page_text: free from the chief defects of the methods for compensation hitherto
adopted, which I believe to be, 1st, irregularly varying figure of the
surface of the mercury in the mercury pendulum; 2nd, friction of solid
on solid, resisting the transformation due to temperature, and so causing
it to take place by jumps in the gridiron pendulum; 3rd, more rapid
following of changes of temperature of the air and surrounding objects
by the uncovered part of the iron rod than by the mercury vessel in
the mercury pendulum; 4th, imperfectness of the compensation when
the temperature is not uniform up and down the space in which
the pendulum moves, a defect which exists in a greater degree in the
mercury pendulum than in the gridiron; and, fifth, the impracticability
of adjusting the compensation of the gridiron according to results of
actual trials at different temperatures. My pendulum consists of a
heavy weight (lead preferable to other solids than the precious metals
on account of its high specific gravity) attached to a short stiff bar of
steel or other suitable material jointed at one end to a long stiff zinc rod
or tube, and supported horizontally by a platinum wire attached to it at
a point between that end and the weight. The zine rod and platinum
bearing wire are approximately equal in length and are each firmly
attached to a solid block constituting the top of the pendulum, which is
hung by one or more short springs attached to this block and to a very
massive fixed block or very rigid and rigidly fixed frame. Or knife
edges may be used for supporting the pendulum, but I prefer springs,
and I prefer a large number of fine round platinum or steel wires to flat
springs as being less liable to flaws and to imperfect elastic action.
When I use more than two bearing wires or springs, I distribute the
weight as nearly equally as may be among all by attaching their upper
ends to transverse springs, each of which yields considerably to its
proportion of weight fixed, and to secure a very definitely fixed virtual
axis for the pendulum's motion I use a massive well fixed horizontal
bar pressing laterally with a cylindrical surface against the bearing wires
with sufficient force to deflect the upper free portions of them through a
considerable angle from the vertical, or I bring each bearing wire round
the top of a strong horizontal bar and down on the other side and
hang upon it a weight equal to its proportion of the whole weight to be
borne. The main weight (or pendulum "bob") is adjustable through
a sufficient range along the horizontal bar to give, the correct com-
pensation for changes of temperature according to practical trial. I use
a. spring joint in preference to a mechanical joint of any ordinary kind

page_text: connecting the horizontal bar with the zinc rod to avoid friction of solid
on solid, but knife edges might answer and would have the advantage
of occupying less space.
55. When it is desired that the clock shall strike the hours, &c., if it is
driven by electro-magnetic power I add mechanism by which a weight
or spring is wound up by the wheelwork during the time the clock is
not striking, to supply energy enough for the striking. Or when water
power is available I employ a water power engine to perform the striking.
One way in which I execute this is by a cylinder with a piston and
valves worked by the piston so that the piston moves to and fro regu-
larly at the proper rate for the striking as long as the valve mechanism
is left in gear. The striking mechanism of the clock throws the water
mechanism into gear at the right time, and throws it out again when the
proper number of strokes has been made.