IMPROVEMENTS IN PRODUCING AND RECORDING ELECTRIC SIGNALS FOR TELEGRAPHIC PURPOSES
Year: 1877

page_text: LETTERS PATENT to Frederick Henry Varley, of Mildmay Park Works,
Highbury, in the County of Middlesex, Telegraph Engineer, for the Invention
of "IMPROVEMENTS IN PRODUCING AND RECORDING ELECTRIC SIGNALS FOR
TELEGRAPHIC PURPOSES."
Sealed the 27th October 1877, and dated the 2nd May 1877.
PROVISIONAL SPECIFICATION left by the said Frederick Henry Varley at
the Office of the Commissioners of Patents on the 2nd May 1877.
FREDERICK HENRY VARLEY, of Mildmay Park Works, Highbury, in the County of
Middlesex, Telegraph Engineer. "IMPROVEMENTS IN PRODUCING AND RECORDING
ELECTRIC SIGNALS FOR TELEGRAPHIC PURPOSES."
Invention has mainly for its object a more direct and effective system of
telegraphing signals by the production of currents of considerable electromative
force, and the use of effective sending and recording instruments capable of in-
dicating the direction and duration of the current corresponding to the elements of
the signaling code, and when employed for a railway block telegraph to permanently
record, such as "clear" or "blocked" at both the sending and receiving ends of the
line, by means of an electro-magnetic switch that holds over the indicator per-
manently after the current has ceased until a reverse current is sent, when the
indicator is again deflected in the like reversed direction.
A telegraph apparatus consists of a battery or arrangement for generating an
electric current, a commutating or transmitting apparatus for directing the currents
through the line, an indicator for receiving or recording the signal, and a bell, gong,
or similar arrangement for calling attention.
In all these essential parts the efficiency of the telegraph system is dependant,
and therefor in this Invention I make a combination of improvements to secure
a complete telegraph apparatus.
The first improvement to the apparatus consists in the battery, which is so con-
structed as to produce powerful electrical currents of great constancy and high
tension.
The second improvement is in the commutating arrangement, by which means
the name or character of the last signal forwarded in permanently shown on the

page_text: face of a reversible tablet, which is moved to the right or left, or raised or lowered
for forwarding the required signals, such as "blocked" or "clear."
The third improvements consists in the mode for keeping the needle permanently
magnetised, concentration of the power generated by the helices, and causing the
indicator to remain permanently deflected, according to the direction of the current
last sent, although the current which has caused the deflection has ceased to flow;
and if by accident or otherwise the indicator should be shifted mechanically to the
reversed direction, it will on being released fly back to the position of the last
indicated signal.
The fourth improvement consists of an arrangement of the connections of the bell,
by which means it automatically switches or commutates another instrument into
circuit, enabling the same line wire to be used for a needle or speaking circuit
without interfering with the recarded block signals.
These several improvements I carry into effect as follows:-I construct a battery,
which is a modification of the oxyde of manganese and carbon, couple the improve-
ments consisting in the mode of constructing the outer cell and the form of the
porous lining; the outer cell is made of glass, porcelain, or other suitable material of
an oblong or oval form, with a neck formed to admit the insertion of the porous cell
on one side, and the carbon plate on the other. Granulated graphite and oxyde of
manganese is placed inside the cell between and surrounding the carbon plate and
porous cells; the open end of the latter is made a little higher than the neck of the
outer cell, and the bottom of the cell has a concave space or hollow for holding
mercury, and keeping it in contact with the zinc element of the battery to maintain
constant amalgamation. The excitent while I prefer to use for this battery is
dilute sulphuric acid, which fill the porous cell containing the zinc element, while
only sufficient to just damp the granulated carbon and oxide of manganese is
poured into the outer jar. This battery gives a tension of about two volts per cell,
whilst it offers small internal resistance and great recuperative power when at rest,
and is especially suited for producing sufficient electro-motive force for giving &
powerful blow or beat on the call bell or gong through a considerable distance of
railway telegraph circuits without necessitating the employment of relays and local
batteries for this purpose.
For the transmitting or sending portion of this Invention I prefer to use a
modification of the commutator described by me in my Patent of June 27, 1873,
and numbered 2232, and described on page 10 and 11, and shewn in Figs. 4, 5, 11,
12, and 13, as applied to a single needle instrument.
The modification consists mainly in employing, in place of the ordinary swing
handle, a vertical axis, to which is jointed a reversible handle or swing tablet
shewing on one side "line blocked," and on the other "line clear," or other suitable
signal; this tablet when pressed will communicate to the receiving portion of the
instrument at the distant station the signal corresponding to the direction in which
the reversible table has been turned, and as the swing tablet shews on one side the
word "blocked," and on the obverse "clear," it requires a distinct act on part of the
signalman to cause a reversal of the current previously sent, whilst at the same
time it points out to him unmistakeably the direction of his sending current. In
addition to this I prefer to use a catch that shall hold over the tablet on whichever
side it may be swung; this catch may be actuated by a spring, or it may be held
over by an electro-magnetic lock under the control of the signalman at the distant
station, in order to render the system more effective. This catch does not prevent
signals from being communicated on the bell or gong, but prevents the reversal of
the indicated signal on the dial of the receiving instrument at the distant station so
long as the catch is unreleased, in order that one line wire may be employed for the
double purpose of block signalling and calling attention by the bell or gong.
The electro-magnetic switch for recording the signals by the permanent deflection
of the indicator I make preferably in the form of a double frame of iron or steel; to
these frames I connect electro-magnets. The two frames I place sufficiently apart
to admit of an induced or permanently magnetized needle to turn or oscillate

page_text: between them, and I employ these frames as conductors of magnetism to maintain
the direction of magnetism in the induced indicating needle, whilst a current
passing through the coils of the electro-magnets shifts the plane of magnetic attrac-
tion from one portion of the frame to the other, causing the needle to be deflected
and held over in the direction of attraction, in which it will remain until a reverse
current be sent through the coils of the electro-magnets, when a like reverse
direction is given to the needle and indicator.
For signalling between block huts, where the distance is short, say, from 2 to 7
miles, I use the same line wire, on which the block signals are conveyed, for a
speaking or single needle circuit. In order to do this I use electro-magnetic coils of
small resistance for the block instruments, and coils of very large resistance for the
speaking instruments, in order that the current used for the speaking circuit shall
not have sufficient electro-motive force to alter the signals indicated on the block
instrument; but in order to further guard against the possibility of the reversal
of the block signal, I prefer to use the back stop of the amature of the bell as a
contact point that puts the needle instrument in circuit; thus should the current
Bent on the needle instrument be sufficiently powerful to cause the attraction of the
armature of the electro-magnetic bell, the needle circuit is at once broken or
interrupted by such attraction, and therefore indicates by the vibration of the
armature that the electro-motive force employed for the needle circuit must be
reduced; but to guard against the reversal of block signal, I make use of the
movement of the armature to open or close a short circuit which cuts out or shunts
the current, which would otherwise produce the deflection of the block indicator;
so long as the current is not sufficiently powerful to produce a complete attraction
of the bell armature, so long is the current shunted from the block instrument.
In order to effect a powerful series of blows upon a call bell, and to economize the
battery power used for such purposes, I employ a contact maker and breaker
similar to that used by me for induction coils in order to obtain greater length of
sparks, that is to say, I use an arinature attached to a swing piece, and carrying &
hammer at one end. This hammer when attracted gives a blow of accumated
force, which I apply to knocking or driving open of a spring contact, and at the
same time the momentum of the moving hammer carries the spring further back,
until the hammer can reach the bell, which is struck with considerable force from
the greater are given to the movement of the hammer. The hammer then recoils
from the force of the spring, which has been driven back by the momentive impact
of the hammer re-acting, and causes the latter to fly back a considerable distance;
and on its return motion the armature is again subjected to the accumulative
attraction of the magnet, and gives a blow somewhat more powerful than the
former.
The hammer stem may be compared to a pendulum, with a force being com-
municated at the return of each beat, accelerating its motion and causing it to
swing over a greater are each successive oscillation.
In order to prevent the hammer from swinging out of range altogether, a spring
is employed as a back stop; this spring acts as an accumulator, and increases the
speed with which the hammer is driven to and fro; by this means a moderate
sized electro-magnet with a resistance, say, of 70 units, can be made to give a very
effective series of beats, bringing out the full tone of a bell weighing 56 lbs., with a
battery current of a few volts tension.
In order to obtain a sufficiently sensitive coil for the speaking instrument to
produce a decisive beat against the stop pins, with a current of small electro-motive
force, I employ an induced or permanently magnetised needle made estatic, or nearly
so, by the permanent induction or conduction of the primary magnet, which I
prefer to attach to the moving axil. This form of coil I find give very sensitive
readings, and the needle is not subject to become demagnetized by the line currents.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Frederick Henry Varley in the Great Seal Patent Office on the
2nd November 1877.
FREDERICK HENRY VARLEY, of Mildmay Park Works, Highbury, in the County
of Middlesex, Telegraph Engineer. "IMPROVEMENTS IN PRODUCING AND RECORDING
ELECTRIC SIGNALS FOR TELEGRAPHIC PURPOSES."
This Invention has mainly for its object a more direct and effective system of
telegraphing signals by the production of currents of considerable electro-motive
force, and the use of effective sending and recording instruments capable of indi-
cating the direction and duration of the current corresponding to the elements of
the signalling code, and when employed for a railway block telegraph fitted to
permanently record signals, such as "clear" or "blocked" at both the sending and
receiving ends of the line, by means of an electro-magnetic switch that holds over
the indicator permanently after the current has ceased until a reverse current is sent,
when the indicator is again deflected in the like reverse direction.
A telegraph apparatus consists of a battery or arrangement for generating an
electric current, a commutating or transmitting apparatus for directing the currents
through the line, an indicator for receiving or recording the signal, and a bell, gong,
or similar arrangement for calling attention. On all these essential parts the
efficiency of the telegraph system is dependent, and therefore in this Invention I
make a combination of improvements to secure a complete telegraph apparatus.
The first improvement in the apparatus consists in the battery, which is so con-
structed as to produce powerful electrical currents of great constancy and high
tension.
The second improvement is in the commutating arrangement, by which means
the name or character of the last signal forwarded is permanently shown on the
face of a reversable tablet, which is moved to the right or left, or raised or lowered,
for forwarding the required signals such as "blocked or " clear."
"
The third improvement consists in the mode of keeping the needle permanently
magnetized, concentration of the power generated by the helices, and causing the
indicator to remain permanently deflected, according to the direction of the current
last sent, although the current which has caused the deflection has ceased to flow, and
if by accident or otherwise the indicator should be shifted mechanically to the reverse
direction it will on being released fly back to the position of the last indicated
signal.
The fourth improvement consists of an arrangement of the connections of the bell,
by which means it automatically switches or commutates another instrument into
circuit, enabling the same line wire to be used for a needle or speaking circuit
without interfering with the recorded block signals.
These several improvements I carry into effect as follows:-I construct a battery,
which is a modification of the oxide of manganese and carbon, couple the improve-
ments consisting in the mode of constructing the outer cell and the form of the
porous lining, the outer cell (A, Fig. 1) being made of glass, porcelain, or other
suitable material of an oblong or oval form, with or without a neck formed to admit
the insertion of the porous cell (B) on one side, and the carbon plate (C) on the
other. Granulated graphite (C) and oxide of manganese are placed inside the
cell A between and surrounding the carbon plate (C) and porous cell B, the open
end of the latter being made a little higher than the neck or mouth D of the outer
cell, and the bottom of the cell having a concave space or hollow, as shewn in
Fig. 2, for holding mercury, and keeping it in contact with the zinc element of the
battery to maintain constant amalgamation. The excitent which I prefer to use for
this battery is diluted sulphuric acid, which fills the porous cell B containing the
zinc element Z, while only sufficient to just damp the granulated carbon, and oxide
of manganese C¹ is poured into the outer jar. This battery gives a tension of about two
volts per cell, while it offers small internal resistance and great recouperative power

page_text: when at rest, and is especially suited for producing sufficient electro-motive force
for giving a powerful blow or beat on the call bell or gong through a considerable
distance of railway telegraph circuits, without necessitating the employment of
relays and local batteries for that purpose.
It is preferable, in order to facilitate the recharging of this battery, to insert a
tube (E) through the carbon and manganese admixture C¹, which reaches nearly to
the bottom of the cell A, in order to admit of the insertion of the suction tube of a
syringe or syphon to extract the spent liquors, and after extraction thereof the cell
can be cleansed by putting it under a jet of water, which is directed first into the
porous cell to wash out the contained salts, and afterwards on to the carbon and
manganese admixture. The water is then extracted by the syringe or syphon
applied to the tube, and the cell thus cleansed is ready for recharging with the
regenerating fluid (preferably containing manganese and sulphuric acid diluted with
ten parts of water), which I preferably make in the following manner and propor-
tions: To one pint of diluted sulphuric acid of the strength of one part acid to ten
parts of water is added one pound of powdered black oxide of manganese. The whole
when intimately mixed forms a fluid paste, which I term the regenerating fluid.
The proportions above given have been found in practice to fulfil all the conditions
requisite for renewing the chemical activity of the battery; but it is not necessary
that the exact proportions given be employed; the acid may be of full strength or
diluted with water.
For low resistance batteries it is preferable to use pure acid. The regenerating
fluid is then added to the cell by pouring it on to the carbon granules C³, between
the interstices of which the fluid paste percolates, and brings the manganese particles
in contact with the active surface of the carbon. The exciting fluid for charging
the porous cell containing the zinc element consists preferably of 1 part of sulphuric
acid to 40 parts of water. In place of glass, porcelain, or stoneware, cells made of
larva or cast in a mixture of molten sulphur and fine sand or pulverised flint, or
red oxides of iron may be employed. Cells thus constructed are exceedingly strong,
and can be shaped of any special form desired; or the cells may be cast in an
admixture of Portland cement and fine sand or flour of flint, which when dry are
placed in a bath of melted paraffin, which renders the cells waterproof.
For the transmitting or sending portion of this Invention I prefer to use a modi-
fication of the commutator described by me in the Specification of my Patent of
June 27th, 1873, No. 2232, on pages 10 and 11 of the said Specification, and shown
on Figs. 4, 5, 11, 12, and 13 of the Drawings thereunto annexed, as applied to a
single needle instrument.
The modification, as shewn in Figs. 3, 4, and 5 of the accompanying Drawings,
consists mainly in employing in place of the ordinary swing handle a vertical axis,
to which is jointed a reversible handle or swing tablet, showing on one side "line
blocked," and on the other" line clear" (as shewn in Fig. 3), or other suitable signal.
This tablet when pressed (as shewn in Fig. 4) will communicate to the receiving
portion of the instrument at the distant station the signal corresponding to the
direction in which the reversible tablet G has been turned, and as the swing tablet
shows on one side the word "blocked," and on the obverse "clear," it requires a
distinct act on the part of the signalman to cause a reversal of the current previously
sent, whilst at the same time it points out to him unmistakeably the direction of
his sending current. In addition to this I prefer to use a catch g that shall hold
over the tablet on whichever side it may be swung; this catch may be actuated by
a spring, or it may be held over by an electro-magnetic lock (H, Fig. 5) under the
control of the signalman at the distant station, in order to render the system more
effective. This catch g does not prevent signals from being communicated on the
bell or gong, but prevents the reversal of the indicated signal on the dial of the
receiving instrument at the distant station so long as the catch is unreleased, in
order that one line wire may be employed for the double purpose of block signalling
and calling attention by the bell or gong.
The electro-magnetic switch for recording the signals by the permanent deflection

page_text: of the indicator, I make preferably in the form of a double frame of iron or steel,
(as shewn in Fig. 6). To these frames I connect electro-magnets K, K¹. The two
frames I place sufficiently apart to admit of an induced or permanently magnetised
needle to turn or oscillate between them, or a space is left for the needle L to
oscillate between, as shown, and I employ these frames as conductors of magnetism
to maintain the direction of magnetism in the induced indicating needle L, whilst a
current passing through the coils of the electro-magnets K, K¹³, shifts the plane of
magnetic attraction from one portion of the frame to the other (as shown by the
arrows), causing the needle to be deflected and held over in the direction of attraction
in which it will remain until a reverse current be sent through the coils of the
electro-magnets, when a like reverse direction is given to the needle and indicator.
M represents the permanent magnet.
For signalling between block huts, where the distance is short, say from 2 to
7 miles, I use the same line wire on which the block signals are conveyed for a
speaking or single needle circuit. In order to do this I use electro-magnetic coils
of small resistance for the block instruments, and coils of very large resistance for
the speaking instruments, in order that the current used for the speaking circuit
shall not have sufficient electro-motive force to alter the signals indicated on the
block instrument. Bnt in order to further guard against the possibility of the
reversal of the block signal, I prefer to use the back stop of the armature of the bell
(N, Fig. 7), as a contact point that puts the needle instrument in circuit; thus
should the current sent on the needle instrument be sufficiently powerful to cause
the attraction of the armature of the electro-magnetic bell O, the needle circuit is at
once broken or interrupted by such attraction, and therefore indicates, by the
vibration of the armature that the electro-motive force employed for the needle
circuit must be reduced; but to guard against the reversal of block signal, I
make use of the movement of the armature to open or close a short circuit
(0¹ and x) which cuts out or shunts the current which would otherwise produce
the deflection of the block indicator. So long as the current is not sufficiently
powerful to produce a complete attraction of the bell armature so long as the current
shunted from the block instrument.
In order to effect a powerful series of blows upon a call bell and to economize the
battery power used for such purposes, I employ a contact maker and breaker,
similar to that used by me for induction coils, in order to obtain greater length of
sparks, that is to say, I use an armature (shown in Fig. 8, by P) attached to a swing
piece (Q), and carrying a hammer at one end. This hammer when attracted gives
a blow of accumated force, which I apply to knocking or driving open a spring
contact maker R, R², and at the same time the momentum of the moving hammer
carries the spring R further back until the hammer can reach the bell, which is
struck with a considerable force from the greater arc given to the movement of the
hammer. The hammer then recoils from the force of the spring, which has been
driven back by the momentive impact of the hammer reacting, and causes the
latter to fly back a considerable distance, and on its return motion the armature is
again subjected to the accumulative attraction of the magnet, and gives a blow
somewhat more powerful than the former.
The hammer stem may be compared to a pendulum with a force communicated
at the return of each beat, accelerating its motion and causing it to swing over a
greater arc each successive oscillation.
In order to prevent the hammer from swinging out of range altogether, a
spring Q¹is employed as a back stop; this spring acts as an accumulator and
increases the speed with which the hammer is driven to and fro. By this means a
moderate sized electro-magnet with a resistance, say of 70 units, can be made to
give a very effective series of beats, bringing out the full tone of a bell weighing
56 pounds, with a battery current of a few volts tension.
In order to obtain a sufficiently sensitive coil for the speaking instrument to
produce a decisive beat against the stop pins with a current of small electro-motive
force, I employ an induced or permanently magnetised needle mado astatic or

page_text: nearly so (shown in Fig. 9), by the permanent induction or conduction of the
primary magnet as represented, the poles being indicated by 8, 8, and n, n, which I
prefer to attach to the moving axle S₁. This form of needle placed in or between a
pair of ordinary needle coils, I find gives very sensitive readings, and the needle is
not subject to become demagnetised by the line currents.
When applying the above apparatus to recording or indicating the movements of
the distant signal semaphore arm, I prefer to use the battery at the signal post, and
the apparatus giving the indications at the signal hut. But as it is most desirable
that the mechanism which commutates the currents should be perfectly well
insulated and mounted, dust and moisture proof, I employ an electric indicator which
makes or breaks contact when exposed to damp air or moisture, and thus indicates
if the apparatus attached to the signal post should become exposed to the weather.
The indicator consists of a strip of metal (Fig. 10), affixed to a piece of thin
wood cut crossway of the grain. This wood expands under the influence of
moisture, and causes the wood and metal couple to assume the curved form chosen
in Fig. 11. This movement I employ to make or break an electric circuit. "
Fig. 13 represents the forms of induced needles, which I employ for the electro-
magnetic switch shown in Fig. 6.
Figure 12 is a form of induced needle that enables the arrangement shown in
Fig. 6 to be employed for a speaking or reading dial..
Fig. 14 represents an electro-magnetic indicator made for showing the movement
of the semaphore arm of the distant signal. It consists of two_electro-magnetic
poles V, VI, having a vertical slot cut out to admit of the needle T swinging freely
between, as shown in Figs. 14 and 15. This needle, when a battery current is
caused to flow around the iron core V, V¹, assumes the vertical position, raising the
somaphore indicator, or in other words, assumes the line of inagnetic attraction.
Fig. 16 shows the construction of the instrument case for block signalling or
speaking instruments, in which the lower half or base of the instrument is made of
inetal, cast iron being preferred for economy of construction and durability of the
wearing parts. The base W being in fact a metal frame or box, on the upper
portion of which is fitted a wood, slate, or ebonite slab X, carrying the com-
mutating portions of the instrument.
The Drawing (Fig. 16) represents the form of frame or base adapted to a speaking
instrument, the boss Y being bored through its centre for the insertion of the axle Z.
The upper portion of the instrument being constructed of wood (preferred from its
lightness to metal) is shown in Fig. 17, and it with the backboard or slab X¹ of
the instrument, forms a dust-tight cover.
It is obvious that the block instruments shown in Fig. 3 can be constructed in a
similar manner, the reversible tablet being jointed to suitable bearing pieces affixed
to the lower half or base of the case made in metal as aforesaid.
Having now particularly described and ascertained the nature and object of the
said Invention, and in what manner the same is to be performed or carried out in
practice, I hereby declare that I claim the Invention of "Improvements in Producing
and Recording Electric Signals for Telegraphic Purposes," combined and arranged
substantially as herein-before described and illustrated by the accompanying
Drawings, in which Invention, however, the following are important and peculiar
points or features :-
1st. The improved construction of battery, substantially as herein-before set forth
and described, and illustrated by Figures 1 and 2 of the accompanying Drawings.
2nd. The employment of a reversible handle in connection with the commutator
for showing "block" and "clear," substantially as herein-before set forth and
described and illustrated in Figs. 3, 4, and 5.
3rd. The electro-magnetic switch as shown in Figs. 6 and 13.
4th. The employment of the back stop of the bell, as shown in Fig 7, for closing
the needle circuit, substantially as described.
5th. The method of augmenting a powerful series of blows upon the call bell,
substantially as described and shown by Fig. 8.

page_text: 6th. The use of the wood and metal couple for indicating the presence of
moisture substantially as described and shown by Figs. 10 and 11.
7th. The construction and arrangement of the base of the instrument case in
metal, substantially as described and shown by Figs. 16 and 17.
It being understood that I do not claim the construction and use of astatic
needles (made of a pair of horse-shoe or rectangular magnets, as shown in Fig. 9),
per se; but I claim the adaptation of same on telegraph circuits for preventing
demagnetization of the more active portion of the needle within the coil, substan-
tially as herein-before described.
In witness whereof, I, the said Frederick Henry Varley, have hereunto set
my hand and seal, this First day of November, in the year of our Lord
One thousand eight hundred and seventy-seven.
Witness,
T. MORGAN,
Secretary,
Inventors' Patent Right Ass"., Ld.,
21, Cockspur St.,
S.W.
FRED³, H. VARLEY. (L.S.)