IMPROVEMENTS IN ELECTRIC TELEGRAPHS AND APPARATUS EMPLOYED IN THEIR CONSTRUCTION, PARTS OF WHICH IMPROVE MENTS ARE APPLICABLE TO OTHER PURPOSES
Year: 1869

page_text: IN
LETTERS PATENT to Samuel Alfred Varley, of 66, Koman Road,
Holloway, in the County of Middlesex, Telegraphic Engineer, for
the Invention of "IMPROVEMENTS IN ELECTRIC TELEGRAPHS AND
APPARATUS EMPLOYED IN THEIR CONSTRUCTION, PARTS OF WHICH IMPROVE
MENTS ARE APPLICABLE TO OTHER PURPOSES."
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PROVISIONAL SPECIFICATION left by the said Samuel Alfred Varley
at the Office of the Commissioners of Patents, with his Petition, ou
the 20th September 1869.
I, SAMUEL ALFRED VARLEY, of 66, Roman Road, Holloway, in the
County of Middlesex, Telegraphic Engineer, do hereby declare the
nature of the said Invention for "IMPROVEMENTS IN ELECTRIC TELEGRAPHS
AND IN APPARATUS EMPLOYED IN THEIR CONSTRUCTION, PARTS OF WHICH IMPROVE-
MENTS ARE APPLICABLE TO OTHER PURPOSEE," to be as follows:-

page_text: Secondly. In the construction of differential galvanometers and
resistance coils used in testing electric circuits and in apparatus employed
in their construction.
Thirdly. In the construction of bells for electric alarums to render
them more sonorous, and in the construction of electric alarums to
render them more sensitive and consequently to require less force to put
them into action.
Fourthly. In the construction of coils and galvanometers, the mag-
netism of which is not influenced by the passage of electric currents of
high tension.
Fifthly. In the construction of galvanic batteries to obtain greater
constancy in their action and to lessen the trouble and the cost of their
maintenance.
Sixthly. In
apparatus.
a method of regulating the speed of telegraph
The
The commutator is an improvement on the commutator employed. in
what are known as Varley's iron cased needle telegraph instruments,
and for which Letters Patent were granted to Cornelius and Samuel
Alfred Varley, bearing date 17th July 1866, No. 1867, and consists of a
solid metal axle working in a metal bush or bearing; this axle has a
transverse piece at one end and is squared at the other end for the
instrument handle to fit upon; two long springs, called for distinction
Nos. 1 and 2, are constructed parallelly to the transverse piece.
lower end of the transverse piece has an arm or cross piece projecting on
either side, against which Nos. 1" and "2" springs press. Nos. "1"
and 2 springs are made as nearly equal in strength as is practicable,
but to prevent the transverse piece from being thrown out of its proper
position by an inequality in springs Nos. 1" and "2" the axle is
maintained in its proper position by means of what are known as
tweezer springs. To other springs Nos. "3" and "4" are arranged
parallelly to Nos. "1" and "2," and project a little beyond Nos. "I”
and 2," where they rest against stops which prevent them coming into
contact with Nos. 1" and
2. Two contact pieces, called "5" and
6" are placed between the transverse piece and Nos.
springs.
1" and ""
The action of this commutator is as follows:--The commutator
is placed in the electric circuit by means of terminals or binding
screws attached to springs Nos., "1" and "2," by means of the
cross

page_text: "
"
piece against which they press. Nos. 8 and 4 springs are
connected to one pole of a galvanic battery, say the copper pole
and the two contact pieces to the other pole of the battery. When
the handle is moved to, say, the right-hand side the circuit becomes
divided and No. "1" spring is pressed against No. "3" and No. "2"
The circuit
spring comes into contact with contact piece No. "6."
is now completed, a positive current flowing through No. "1" spring
and a negative current through No. "2." If the handle be moved
to the left the position of the battery poles in respect to the electric
circuit becomes reversed, and in this way the currents can be sent
through the circuit in either direction as desired. When these
commutators are used for what are known as block signalling circuits
in which the normal state is for the circuit to be closed; the upper end of
the transverse piece has a hole drilled through the case of the in-
strument which corresponds with the hole in the transverse piece
when the handle of the instrument is moved over on one side; and the
circuit is kept closed by inserting a pin through the front of the case
and the upper end of the transverse piece which prevents the handle
from returning.
I also construct my commutators for reversing the direction of
electric currents through telegraph circuits of two levers working
side by side on axles which pass through metal blocks. These levers
move up and down in a somewhat similar way to pianoforte keys.
Ebonite or other suitable insulating material is attached to one end of
each of the levers which for distinction we call the "back ends," and
springs called "back end springs" press upon the pieces of ebonite,
keeping the "back ends" of the levers depressed and forcing the levers
on the other side of the axle upwards and against a metal bar called
"the bridge." The "bridge" works in blocks and can be twisted round to
bring fresh surfaces against the levers and to allow the places of contact
to be readily cleaned. Over the back end springs two other springs
called upper springs" are mounted. The upper springs are prevented
touching the "back end springs" by stops which arrest their motion
downwards beyond a fixed extent. Underneath the "front end of the
levers there is a piece of metal called the front contact.
66
The action of this commutator is as follows:-The commutator. is
placed in the telegraph circuit by means of two binding screws attached
to the levers, the continuity being maintained by means of the bridge

page_text: 33
connecting the two levers. The front contact" is connected to one pole
of a galvanic battery, the other battery pole is connected to the " upper
springs; the back end spring of the right-hand lever is connected to
the left-hand lever, and the back end" spring of the left-hand lever to
the right-hand lever. On depressing the front end of, say, the right-hand
lever the circuit is divided and the depressed lever comes in contact
with the front contact, raising at the same time the back end spring
which is connected with the left-hand lever against the upper springs,
and the electric circuit is completed. If the left-hand key be depressed
the circuit is also closed in the way just described, but the direction of
the polarity is reversed. When it is desired to keep the circuit closed
for any length of time I keep one of the levers depressed by means of a
metal pin passing through a metal block connected to the front contact.
When this commutator is used for speaking instruments and railway
signalling circuits the coils by which the signals are read are mounted
on separate boards. from the commutator; the advantages obtained
by this means are greater compactness as well as portability. In the
usual construction of differential galvanometers the two insulated wires
forming the coil are joined together at one end. Should there be any
leakage between the wires, which sometimes occurs, it cannot be readily
detected, the wires also very frequently do not have the same action on
the magnetic needle, either from the two coil wires not being correctly
balanced or from one of them having become heated in consequence of
the circuit being closed through it for a longer interval than through the
other.
My improvement consists in keeping the two insulated wires forming
the coils separate from one another at both ends and connecting either
ends together when using the instrument as I desire. 1 prefer to do this
by means of a commutator, which consists of a metal barrel having two
eccentrics, called for distinction Nos. 1" and 2." The four extremities
of the two insulated coil wires are connected to metal springs which press
upwards against metal cocks or contact pieces. If the commutator
barrel be turned over on one side two of these springs are depressed by
eccentric No. 1 and connected together. If the barrel be turned to the
opposite side eccentric No. 1 is removed from the two springs, which
now press against their respective contact pieces, and the two other
springs are depressed and connected together by eccentric No. 2. If the
commutator barrel be placed midway the eccentrics do not touch, the

page_text: four brass springs, which now press against their respective contact
pieces and are quite separate from one another, and can be tested at any
time to ascertain if they be perfectly insulated from one another. When
testing a telegraph line with a differential galvanometer the circuit is
closed through one of the galvanometer coils and the telegraph line,
and through the other coil of the galvanometer and a set of resistance
coils, which are thrown into circuit one after the other until the resist-
ance coil circuit balances the line circuit. When this is the case the
magnetic needle is not deflected and remains stationary. The resistance
requisite to balance. the line circuit is now read off on a scale attached
to the set of resistance coils. If however the two galvanometer coils do
not exercise an equal influence on the magnetic needle the reading
obtained from the scale does not correctly indicate the resistance of the
telegraph line. When testing with my improved galvanometer the
commutator is turned over on one side to the other, and the connec-
tions between the two galvanometer wires, the resistance coil circuit,
and the line circuit are reversed. When using this instrument the
switch is first turned over on one side and the circuit balanced by means
of the resistance coils. The resistance is now read off on the scale, the
commutator is then turned over on to the opposite side, the circuits
balanced as before, and the resistance read off. If the action of the
galvanometer coils on the magnetic needle is not equal the two readings
will differ from one another. The mean between the two readings will
give the correct resistance.
1 prefer to make the width between the coil checks of my improved
differential galvanometer considerably wider than the length of the
magnetic needle inside the coils, the action of the two insulated wires
upon the magnet is then more uniform.
circuits through
segments; these
I construct the commutators for closing electric
resistance coils of a circle of metal divided into
segments are connected together through the resistance coils, which are
wrapped on tubular metal bobbins which fit on to and are attached to
brass or copper rods screwed into the segments. For greater compact-
ness the bobbins are usually made double, and two resistance coils, the
one below the other, are wrapped on the bobbins. When the coils are
arranged as equal resistances two metal arms, insulated from one another
but working from the centre of the circle, pass over the segments and
are pressed against them by means of springs. These arms move inde-

page_text: репчеты
over the segments. When the apparatus is in use the circuit is closed
through one of the metallic arms, the segment on which it presses
through the coil or coils included in the circuit, and through the
segment on which the second arm presses. By shifting the arms
over the segments and approaching or removing them farther apart
the circuit can be closed through any individual coil or any number
of them, and the desired combination made with great case and
rapidity.
An important feature in the construction of this commutator is that
the metallic continuity is very complete and does not depend upon the
simple contact of metal with metal. The connections are made through
flexible metallic ropes which allow the arms to move freely one whole
revolution. The ropes, however, may be dispensed with when great
accuracy is not so important. The only part of the circuit where the
contact is made by metal rubbing on metal is where the arms rest upon the
segments and these are kept clean and bright by the burnishing action
of the arms passing over them. The commutator is also constructed
with holes between the segments, and the circuit can be closed by the
insertion of pegs which fit into them. The object of this is to cut out a
coil or coils if defective. When the coils are arranged in progressive
resistances the moveable metallic arms are dispensed with, and the
circuit closed by means of pegs. A leading feature in the construction
of this commutator is that greater insulation is obtained than in the
ordinary construction, greater compactness in the instrument, and
greater facility given for removing the coils if defective. The resistance
opposed by metallic conductors to an electric current is influenced by
the temperature, and the construction of differential galvanometers and
resistance coils, where the greatest accuracy is required is rendered
diflicult in consequence of the atmospheric temperature continually
changing. To obviate this difficulty I maintain the temperature of the
room in which they are made at one equal temperature by means of a heat
regulator which regulates a hot-water system, which is constructed in
the following way: I take two plates of metal, which may be circular,
and on the surfaces of these I attach lead or pewter by means of ordinary
plumbers' solder. These plates are in some cases made entirely of
pewter and are kept at a fixed distance apart by means of a support in
the centre or by pillars. A number of holes corresponding to one another

page_text: are bored through the plates and leaden coatings. Pipes made of lead,
or what is known as composition pipe, of a suitable length are placed
in the holes in the plate, each pipe passing through the corresponding
holes of the upper and lower plates connecting them together. The
pipes are then rivetted by driving in a taper plug in the mouth of the
pipes making water-tight joints. The pipes are then cased in by
wrapping a sheet of metal over the pipes and soldering it to the upper
and lower plates and joining the sheet of metal at the lap joint also by
solder. In this way a tubular boiler is constructed in which the
surfaces exposed to the gas are entirely of lead or pewter, metals not
readily acted upon by the products of combustion of coal gas, which
is so detrimental to boilers of the ordinary construction. The boiler is
placed on the top and attached to a water casing in which the gas
burner is placed. In this water casing there is a gutter, which catches
any water that is produced in the combustion of the gas and prevents it
falling upon the burner. A pipe is attached to this gutter to lead away
the water as fast as it is produced. A chimney is attached to the upper
end of the boiler to cause a draught and also to lead away the products
of combustion. In this chimney there is also a gutter to collect any
water that may be deposited in it, and which is lead away by means
of a pipe as before described. The uniformity of temperature is
maintained by means of a mercurial valve, which is acted upon
thermometrically by the expansion of spirits of wine in a suitable
chamber; water or airy other liquid may be substituted for spirits of
wine. The expansion of the liquid forces up a column of mercury and
closes the mouth of the tube through which the gas passes and cuts it
off from the main burner. When the temperature falls and the liquid
consequently contracts, the mercury falls and the gas is again turned
on and relighted by means of a small independent burner which is kept
constantly burning.
The coils of the differential galvanometers after being wrapped are
boiled in melted paraffine for sometime to secure very perfect insulation;
they are then removed and allowed to cool, and I test them for
insulation by means of a small Leyden arrangement consisting of an
open glass tube, the inner coating of which consists of a piece of thin
brass or copper soldered to a metal ring at one end of the glass tube.
A pasteboard holder lined with tin-foil is placed over the tube to hold
it, forming the outer coating and projecting a little below the other end

page_text: of the tube.
A circular cushion is placed into the projecting portion
of the pasteboard tube, and a small charge is given by rubbing a glass
or ebonite tube through the cushion and inside the tube; this charge
is conveyed to the coil wires, and the test consists in their capability
of retaining it.
Bells used for electric alarums are made of an alloy of tin and copper,
and as the most sonorous composition is very hard and brittle, and
difficult to work, an alloy is generally employed which is less sonorous
but more easily worked. Instead of casting bells in the ordinary way
in sand moulds, I pour molten metal into a concave mould of the shape
of the exterior of the bell, and while the metal is still liquid force a dic
by means of a fly press or any other suitable means into the mould, this
die is a counterpart of the inside of the bell and forces the metal into the
shape desired; the bells produced by this means are very uniform and
very smooth, and as the surface does not require turning the most
sonorous mixture of tin and copper can be employed in their
construction.
I construct my electric alarums to render them very sensitive to
weak electric currents of one pair of electro-magnets or two smaller
pairs. An armature working on an axle in its centre is mounted over
the electro-magnets and the circuit closed through one pair of the
electro-magnets at a time. The circuit is closed by the armature
resting against a spring contact, the motion of which is limited. When
an electric current is sent through the instrument the armature is
attracted by the magnet or pair of magnets through which the circuit
is closed. The contact spring follows the armature in its descent a
definite determined account. The armature descends still further by
the momentum it has acquired and comes in contact with a second
contact spring and closes the electric circuit through the other electro-
magnet or pair of electro-magnets. It is now attracted on the other
side when it leaves contact spring No. 2 and closes the circuit through
contact spring No. 1. In this way an oscillating motion is given to the
armature so long as the battery is connected to the alarum. Striking
hammers are attached to either ends of the armature and 2 bells
arranged underneath them. One of the hammers strikes the bell at eacli
oscillation of the armature. 'As the armature is mounted in the centre
and nearly equally balanced a very small amount of electric force is
sufficient to put it into motion. To prevent the bells being struck by

page_text: oscillation I mount a soft iron bar which hangs by gravity perpendicularly
and a pin projecting from one of the hammers comes in contact with
this bar, should there be any oscillation, and the hammer is arrested
previously to its striking the bell. I do not confine myself to this
method of arresting the hammer if put into motion by oscillation, or to
the method described of making the contacts by means of springs
whose motion is limited, I adopt sometimes the methods described in
previous Inventions, and for which Letters Patent were granted to
myself and Samuel Manley Martin, bearing dates 29th of January 1868,
No. 315 and 28th July 1868, No. 2369.
I construct the coils for telegraph instruments which are not
influenced by the passage of currents of high tension, as is the case in
the coils ordinarily adopted, in the following manner:-I take a circle of
soft iron which may be attached to a piece of non-magnetic metal and
divide it, forming it into two, and sometimes four segments.
Four
small electro-magnets are connected to the segments; these electro-
magnets are joined together by permanent bar magnets which induce
magnetism in the soft iron cores of the electro-magnets. A soft iron
needle mounted on an axle works in the centre of the circle, and when
the circuit is closed through the electro-magnets the magnetism induced
by the permanent magnet in the electro-magnets becomes increased in
the two opposite segments of the divided iron circle and lessened in the
two other segments, and consequently the soft iron needle becomes
deflected over on the one side. If the circuit be closed in the reverse
direction the magnetism becomes increased in the segments on the
opposite side and the needle is deflected in the reverse direction.
In the usual construction of galvanic batteries there is considerable
waste of material when the battery is not being used. In what are
known as constant batteries where two metallic salts are employed the
power of the battery is much weakened by the deposition of the
negative metal upon the positive element. In batteries where there is
free acid great loss arises from the local action of the acid upon the
positive element of the battery, which is usually zinc. The force of the
battery after it has been in action for a short time becomes considerably
weakened by what is termed the polarization of the negative elements,
arising from the adherence of the hydrogen which is generated.
construct my batteries of cast-iron plates, or of what is known as gas
carbon, wrapped round with a highly negative metal wire; these plates
are corrugated or ribbed. I obtain by this means a greatly increased
I

page_text: surface in the negative elements and the ribs part with the hydrogen
more freely than flat surfaces, and consequently there is not so much
polarization. In some cases I employ platina or other suitable wire, or
two wires, one of which is more negative than the other for the negative
elements of the batteries, and I thereby obtain a
which is not so subject to polarization as flat plates.
be in the form of wire gauze or wrapped upon a frame.
I prefer
surrounding the positive elements of the battery entirely by the negative
elements so that the whole surface of the positive elements exposed to
the liquid may be active.
very large surface
The wire used may
When I require the batteries to be very constant and to last
a long time I prefer exciting them with a solution of a neutral salt,
such as common table salt, salammoniac, a solution of alum, or of
any other suitable salt, and to reduce the local action I prefer the
zinc plates to be amalgamated. The battery troughs are closed on
the top and made water-tight by bolting down the lid with a layer
of vulcanized india-rubber between, or by any other suitable means, a
small pipe being inserted to allow any gas which may be generated to
escape. The battery trough is mounted on metal trunnions on which it
can be revolved; these trunnions form the battery connections. The
exciting fluid is only filled up about half way up the plates. When the
power of the battery becomes weakened from the polarization of the
plates the battery trough is turned half way round and the other half of
the plates becomes immersed. The surfaces of the plates previously
immersed are now exposed to the air and quickly become depolarized.
The shape of the troughs may be varied; they may be made circular
and a
constant motion communicated to them if desired. When
galvanic batteries are required to be put into action only occasionally
the trough is made double the depth of the battery plates.
In one
position the plates are out of the exciting liquid, in the other they are
immersed. This latter arrangement is very useful where powerful
currents are required for only a short time, as the plates are entirely
out of the exciting fluid, excepting during the time the batteries are in
active work.
When I require the motion of the electric apparatus to be maintained
at a uniform rate. I construct a trainwork of wheels, which may be set
in motion either by a weight, or by a spring, or by any other suitable
way. This trainwork sets in motion an electric governor which consists

page_text: metal.
of an axle driven by the trainwork and having two arms working on a
pin or spring joint. The upper portion of the axle carries a disc of
The axle is divided and joined together by an insulating
substance, so that the lower portion of the axle carrying the arms is not
in electric connection with the upper portion of the axle carrying the
disc. When the trainwork is set in motion the two arms fly out by.
centrifugal force, and when the speed attained is greater than that
desired the arms touch the disc above them and close an electric circuit
through an electro-magnet, which may be made to retard the disc by
the resistance which magnetism opposes to the motion of a diamagnetic
metal or by the attraction of a lever against the periphery of a disc.
The enclosing the battery in a water-tight trough and mounting it
on trunnions so that it can be revolved admits of other useful applica-
tions besides these herein-before described. One useful application is
to that of electrotyping; the metal deposited in a revolving trough is
much smoother and more uniform than that deposited in a stationary
trough. When I use the battery for this purpose I make the decompo-
sition cell in which the metal is deposited by preference a part of the
battery trough, or it may attached to the trough so that it may revolve
with the battery.
The method described of maintaining the temperature uniform for the
manufacture of sifferential galvanometers and resistance coils may be
also usefully applied in nearly all cases where a uniform temperature is
desirable.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Samuel Alfred Varley in the Great Seal Patent
Oflice on the 19th March 1870.
TO ALL TO WHOM THESE PRESENTS SHALI. COME, I, SAMUEL
ALFRED VARLEY, of 66, Roman Road, Holloway, in the County of
Middlesex, Telegraphic Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twentieth day of September, in the year
of our Lord One thousand eight hundred and sixty-nine, in the thirty-
third year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said Samuel Alfred Varley, Her special licence

page_text: that I, the said Samuel Alfred Varley, my executors, administrators,
and assigns, or such others as I, the said Samuel Alfred Varley, my
executors, administrators, and assigns, should at any time agree with,
and no others, from time to time and at all times thereafter during the
term therein expressed, should and lawfully might make, use, exercise,
and vend, within the United Kingdom of Great Britain and Ireland,
the Channel Islands, and Isle of Man an Invention for "IMPROVEMENTS
IN ELECTRIC TELEGRAPHS AND IN APPARATUS EMPLOYED IN THEIR CONSTRUCTION,
PARTS OF WHICH IMPROVEMENTS ARE APPLICABLE TO OTHER PURPOSES," upon the
condition (amongst others) that I, the said Samuel Alfred Varley, my
executors or administrators, by an instrument in writing under my, or
their, or one of their hands and seals, should particularly describe and
ascertain the nature of the said Invention, and in what manner the
same was to be performed, and cause the same to be filed in the Great
Seal Patent Office within six calendar months next and immediately
after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Samuel Alfred Varley, do hereby
declare the nature of my said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and
by the following statement:-
This Invention relates to improvements in apparatus for opening and
closing electric circuits; to improvements in the construction of differential
galvanometers and resistance coils used for testing electric circuits, and
in apparatus employed in their construction; also to improvements in
the manufacture of bells for electric alarums; to improvements in the
construction of coils and galvanometers, the magnetism of which is not
influenced by the passage of electric currents of high tension; and also
to improvements in the construction of galvanic batteries, and the regu-
lation of the speed of telegraph apparatus.
My Invention consists of improvements, firstly, in the construction of
commutators for closing electric circuits and changing the direction of
electric currents.
Secondly. In the construction of differential galvanometers and
resistance coils used in testing electric circuits, and in apparatus
employed in their construction.
Thirdly. In the construction of bells for electric alarums to render
them more sonorous, and in the construction of electric alarums to

page_text: render them more sensitive, and consequently to require less force to
put them into action.
Fourthly. In the construction of coils and galvanometers, the mag-
netism of which is not influenced by the passage of electric currents of
high tension.
Fifthly. In the construction of galvanic batteries to obtain greater
constancy in their action and to lessen the trouble and the cost of their
maintenance.
Sixthly. In a method of regulating the speed of telegraph apparatus.
The commutator is an improvement on the commutator employed in
what are known as Varley's iron cased needle telegraph instruments, and
for which Letters l'atent were granted to Cornelius and Samuel Alfred
Varley, bearing date 17th July 1866, No. 1867, and consists of a solid
metal axle working in a metal bush or bearing. This axle has a trans-
verse piece at one end and is squared at the other end for the instrument
handle to fit upon, the upper end of the transverse piece works between
two projecting pieces of metal forming part of the case, and which limit
the motion of the axle. Two long springs, called for distinction Nos. "1"
and "2," are constructed parallel to the transverse piece. The lower end
of the transverse piece has an arm or cross piece projecting on either side
against which Nos. "1" and "2" springs press. Nos. "1" and "2"
springs are made as nearly equal in strength às is practicable, but to
prevent the transverse piece from being thrown out of its proper position
by any unequality in springs Nos. "1" and "2," the axle is maintained
in its proper position by means of what are known as tweezer springs.
Two other springs Nos. "3" and "4" are arranged parallel to Nos. "1"
and "2" and project a little beyond Nos. "1" and "2" where they rest
against stops which prevent them coming into contact with Nos. "1"
and "2." Two contact pieces called "5" and "6" are placed below
the "transverse pieces" and between Nos. "1" and "2" springs.
<<
The action of this commutator is as follows:-The commutator is
placed in the electric circuit by means of terminals or binding screws
attached to springs Nos. "1" and "2," and the circuit is completed
between Nos. "1" and "2" by means of the cross piece" against
which they press. Nos. "3" and "4" springs are connected to one pole
of a galvanic battery, say, the copper pole and the two contact pieces to
the other pole of the battery. When the handle is moved to, say, the
right hand side the circuit becomes divided, and No. "1"
spring. is

page_text: pressed against No. "3" and No. "2" spring comes into contact with
contact piece No. "6." The circuit is now completed, a positive current
flowing through No. "1" spring and a negative current through No. " 2."
If the handle be moved to the left the position of the battery poles in
respect to the electric circuit becomes reversed, and in this way the
currents can be sent through the circuits in either direction as desired.
as block
When these commutators are used for what are known
signalling circuits in which the normal state is for the circuit to be
closed, the upper end of the transverse piece has a hole drilled through
it and there is a hole drilled through the case of the instrument which
corresponds with the hole in the transverse piece. When the handle of
the instrument is moved over on one side the circuit is kept closed by
inserting a pin through the front of the case and upper end of the
transverse piece which prevents the handle from returning.
"
I also construct my commutators for reversing the direction of electric
currents through telegraph circuits of two levers working side by side on
axles which pass through metal blocks. These levers move up and down
in a somewhat similar way to pianoforte keys. Ebonite or other suitable
insulating material is attached to one end of each of the levers, which
for distinction I call the back ends" and springs called "back end
springs
press upon the pieces of ebonite keeping the "back ends" of
the levers depressed and forcing the levers on the other side of the axle
upwards and against a metal bar called "the bridge." The "bridge"
works in blocks and can be twisted round to bring fresh surfaces against
the levers and to allow the places of contact to be readily cleaned. Over
the "back end springs" two other springs called
upper springs
mounted. The upper springs are prevented touching the "back end
springs" by stops which arrest their motion downwards beyond a fixed
extent.. Underneath the "front end of the levers" there is a piece of
metal called the front contact.".
"
are
The action of this commutator is as follows:-The commutator is
placed in the telegraph circuit by means of two binding screws attached
to the levers, the continuity being maintained by means of the bridge
The front contact" is connected to one
connecting the two levers.
pole of a galvanic battery, the other, battery pole is, connected to the
upper springs;" the back end spring of the right-hand lever is con-
nected to the left-hand lever, and the "back end" spring of the left-
hand lever is connected to the right-hand lever. On depressing the front
end of, say,
the right-hand lever the circuit is divided and the depressed
"

page_text: lever comes in contact with the front contact, raising at the same time
the "back end spring," which is connected with the left-hand lever
If the
against the upper springs, and the electric circuit is completed.
left-hand key be depressed the circuit is also closed in the way just
When it is
described, but the direction of the polarity is reversed.
desired to keep the circuit closed for any length of time, I keep one of
the levers depressed by means of a metal pin passing through a metal
block connected to the front contact. When this commutator is used
for speaking instruments and railway signalling circuits, the coils and
the commutator are mounted by preference upon separate boards, the
advantage obtained by so doing is greater compactness, the instrument
taking up less room; it is sometimes however more convenient to mount
the coils and the commutator together.
In the usual construction of
differential galvanometers the two insulated wires forming the coils are
joined together at one end. Should there be any leakage between the
wires, which sometimes occurs, it cannot be readily detected, the wires
also very frequently do not have the same action on the magnetic
needle, cither from the two coil wires not being correctly balanced or
from one of them having become heated in consequence of the circuit
being closed through it for a longer interval than through the other.
My improvements consist in keeping the two insulated wires forming
the coils separate from one another at both ends and connecting either ends
together when using the instrument as I desire. I prefer to do this by
means of a commutator which consists of a metal barrel having two
eccentrics, called for distinction Nos. "1" and "2:" The four extremities
of the two insulated coil wires are connected to metal springs, which
press upwards against metal cocks or contact pieces. If the commutator
barrel be turned over on one side, two of these springs are depressed by
eccentric No. "1" and connected together. If the barrel be turned to
the opposite side eccentric No. "1" is removed from the two springs, which
now press against their respective contact pieces, and the two other
springs are depressed and connected together by eccentric No. "2."
If the commutator barrel be placed midway the eccentrics do not
touch the four brass springs which now press against their respective
contact pieces, and can be tested to ascertain if they be perfectly insu-
lated from one another. When testing a telegraph line with a differential
galvanometer the circuit is closed through one of the galvanometer
coils and the telegraph line, and through the other coil of the galvano-
meter and a set of resistance coils which are thrown into circuit until

page_text: the resistance coil circuit balances the line circuit. When this is the
case the magnetic needle is not deflected and remains stationary. The
resistance requisite to balance the line circuit is now read off on a scale
attached to the set of resistance coils. If however the two galvanometer
coils do not exercise an equal influence on the magnetic needle the
reading obtained from the scale does not correctly indicate the resistance
of the telegraph line. When testing with my improved galvanometer
the commutator is turned over from one side to the other, and the
connections between the two galvanometer wires, the resistance coil
circuit and the line circuit are reversed. When using this instrument,
the switch is first turned over on one side and the circuit balanced by
means of the resistance coils; the resistance is now read off on the
scale; the commutator is now turned over on to the opposite side, the
circuits balanced as before, and the resistance read off. If the action
of the galvanometer coils on the magnetic needle is not equal the two
readings will differ from one another. The mean between the two
readings will give the correct resistance.
I prefer to make the width between the coil cheeks of my improved
differential galvanometer considerably wider than the length of the
magnetic needle inside the coils the action of the two insulated wires
upon the magnet is then more uniform.
I construct the commutators for closing electric circuits through
resistance coils of a circle of metal divided into segments. These
segments are connected together through the resistance coils, which are
wrapped on tubular metal bobbins which fit on to and are attached to
brass or copper rods screwed into the segments. For greater compactness
the bobbins are usually made double, and two resistance coils, the one
below the other, are wrapped on the bobbins. When the coils are
arranged as equal resistances two metal arms, insulated from one another
but working from the centre of the circle pass over the segments and
are pressed against them by means of springs. These arms move indepen-
dently of one another and can be shifted backwards and forwards over
the segments. When the apparatus is in use the circuit is closed
through one of the metallic arms, the segment on which it presses
through the coil or coils included in the circuit, and through the
segment on which the second arm presses. By shifting the arms over
the segments and approaching or removing them further apart the
circuit can be closed through any individual coil or any number of
them, and the desired combination made with great ease and rapidity.

page_text: are
An important feature in the construction of this commutator is that the
metallic continuity is very complete and does not depend upon the
simple contact of metal with metal. The connections are made through
flexible metallic ropes which allow the arms to move freely, one whole
revolution; the ropes, however, may be dispensed with when great
accuracy is not so important. The only part of the circuit where the
contact is made by metal rubbing on metal is where the arms rest upon
the segments, and these are kept clean and bright by the burnishing
action of the arms passing over them. The commutator is also
constructed with holes between the segments, and the circuit can be
closed by the insertion of pegs which fit into them. The object of
this is to cut out a coil or coils if defective. When the coils are
arranged in progressive resistances the movable metallic armis
dispensed with, and the circuit closed by means of pegs. A leading
feature in the construction of this commutator is that greater insulation
is obtained than in the ordinary construction, greater compactness in
the instrument, and greater facility given for removing the coils if
defective. The resistance opposed by metallic conductors to an electric
current is influenced by the temperature, and the construction of
differential galvanometers and resistance coils where the greatest accuracy
is required is rendered difficult in consequence of the atmospheric
temperature continually changing. To obviate this difficulty I maintain
the temperature of the room in which they are made at one equal
temperature by means of a heat regulator which regulates a hot water
system, and which is constructed in the following way take two
plates of metal which may be circular and on the surfaces of these I
attach lead or pewter by means of ordinary plumber's solder. These
plates are in some cases made entirely of pewter and are kept at a fixed
distance apart by means of a support in the centre or by pillars. A
number of holes corresponding to one another are bored through the
plates and leaden coatings. Pipes made of lead or what is known as
composition pipe of a suitable length are placed in the holes in the
plates, each pipe passing through the corresponding holes of the upper
and lower plates connecting them together. The pipes are then rivetted
by driving taper plugs in the mouth of the pipes making water-tight
joints. The pipes are then cased in by wrapping a sheet of metal over
the pipes and soldering it to the upper and lower plates and joining
the sheet of metal at the joint also by solder. In this way a tubular
boiler is constructed in which the surfaces exposed to the gas are

page_text: entirely of lead or pewter, metals not readily acted upon by the products
of combustion of coal gas which is so, detrimental to boilers of the ordinary
construction. The boiler is placed on the top and attached to a water
casing in which the gas burner is placed, in this water casing there is a
gutter which catches any water that is produced by the combustion and
prevents it falling upon the burner, a pipe is attached to this gutter to
lead away the water as fast as it is produced; a chimney is attached to
the upper end of the boiler to cause a draught and also to lead away
the products of combustion; in this chimney there is also a gutter to
collect any water that may be deposited in it and which is lead away by
means of a pipe as before described, the uniformity of temperature
is maintained by means of a mercurial valve which is acted upon
thermometrically by the expansion of spirits of wine in a suitable
chamber. Water or any other liquid may be substituted for spirits of
wine or the valve may be acted upon for the expansion of metals which
may be made to act directly upon the valve or to close an electric
circuit which renders an electro-magnet active and sets in motion an
iron lever that acts upon the valve. The boiler is connected to a system
of hot water pipes and the chamber heated by the circulation of hot
water through the pipes. When the temperature exceeds in the least
degree that required the mercury forming the valve becomes raised and
closes the mouth of the tube through which the gas passes to the burner
that heats the boiler and cuts off the supply of gas. On the temperature
of the room becoming lowered the gas is again turned on and relighted
by a small independent burner which is always kept burning when the
apparatus is at work.
The coils of the differential galvanometers after being wrapped are
boiled for some time in melting paraffine to secure very perfect insulation,
they are then removed and allowed to cool, and I test them for insulation
by means of a small Leyden arrangement consisting of an open glass
tube, the inner coating of which consists of a piece of thin brass or
copper soldered to a metal ring attached to one end of the glass tube.
A pasteboard holder lined with tinfoil is placed over the tube to hold it,
forming the outer coating of the Leyden arrangement and projecting a
little below the other end of the tube, in which projecting portion a
circular cushion is placed. A long glass tube is passed through the
"circular cushion" and the Leyden arrangement is charged statically
by rubbing the long tube backwards, and forwards, this charge is

page_text: conveyed to the insulating wires forming the coils of the galvanometers,
and the test consists in the capability of the coil wires to retain the
charge.
Bells used for electric alarums are made of an alloy of tin and copper,
and as the most sonorous composition is very hard and brittle and
difficult to work an alloy is generally employed which is less sonorous
but more easily worked in consequence of its greater softness. Instead
of casting bells in the ordinary way in sand moulds I pour the molten
metal into a concave mould and force a die by means of a fly press or
other suitable means into the mould while the metal is still fluid or
before the metal has ceased to be ductile, the die which is forced in is
a counterpart of the inside of a bell and forces the ductile metal into the
desired shape. The bells produced by this means are very true and
uniform, and the surfaces being very smooth it is not necessary to turn
them in a lathe to remove roughness or inequalities, and consequently a
more sonorous and harder alloy of tin and copper can be employed in
their construction.
The
I construct my electric alarums to render them very sensitive to weak
electric currents of one pair of electro-magnets or two smaller pairs.
An armature working on an axle in its centre is mounted over the
electro-magnets and the circuit closed through one pair of electro-
magnets at a time. The circuit is closed by the armature resting
against spring contacts, the motion of which is limited. When an electric.
current is sent through the instrument the armature is attracted by the
magnet or pair of magnets through which the circuit is closed.
contact spring follows the armature in its descent a definite determined
amount. The armature descends still further by the momentum it has
acquired and comes in contact with a second contact spring and closes,
the electric circuit through the other electro-magnet or pair of electro-
magnets. It is now attracted on the other side, when it leaves contact
spring Number 2 and closes the circuit through contact 'spring Number 1.
In this way an oscillating motion is given to the armature as long as
the battery is connected to the alarum. Striking hammers are attached
to either ends of the armature, and two bells arranged underneath them.
One of the hammers strikes the bell at each oscillation of the armature.
As the armature is mounted in the centre and nearly equally balanced
a very small amount of electric force is sufficient to put it into motion.
To prevent the bells being struck by oscillation I mount soft iron bars

page_text: which hang by gravity perpendicularly, and a pin projecting from the
hammers comes in contact with these should there be any oscillation,
and the hammers are arrested previously to striking the bell. I do not
confine myself to this method of arresting the hammers if put into
motion by oscillation or to the method described of making the contacts
by means of springs whose motion is limited. I adopt sometimes the
method described in previous Inventions, and for which Letters Patent
were granted to myself and Samuel Manly Martin, bearing date Twenty-
ninth of January One thousand eight hundred and sixty-eight, Number
315, and Twenty-eighth of July One thousand eight hundred and sixty-
eight, No. 2369, the arrangement I prefer is shewn in Figure 14.
I construct the coils for telegraph instruments the magnetic needles
of which are not influenced by the passage of currents of high tension as
is the case in the coils ordinarily adopted in the following manner-I
take a circle of soft iron which may be attached to a piece of non-
magnetic metal and divide it, forming it into two and sometimes into
four segments; four small electro-magnets are connected to the segments.
These electro-magnets are joined together by a permanent bar magnet
which induces magnetism in the soft iron cores of the electro-magnets.
A soft iron needle mounted on an axle works in the centre of the circle,
and the circuit is closed through the electro-magnets, the magnetism
induced by the permanent magnet in the electro-magnets becomes
increased in the two opposite segments of the divided iron circle and
lessened in the two other segments, and consequently the soft iron needle
becomes deflected over on the one side; if the circuit be closed in the
reverse direction the magnetism becomes increased in the segments on
the opposite side, and the needle is deflected in the reverse direction.
The construction above described is very efficient for actuating what are
known as alphabetical telegraphs where a driving escapement sets in
motion a toothed wheel carrying a pointer which points out the letters of
the alphabet or other characters painted upon a dial.
It is also very
suitable for some descriptions of railway signalling apparatus.
In the usual construction of galvanic batteries there is considerable
waste of material when the battery is not being used. In what are
known as constant batteries where two metallic salts are employed the
power of the battery is much weakened by the deposition of the negative
element upon the positive element. In batteries where there is free acid
great loss arises from the local action of the said acid upon the positive

page_text: element of the battery, which is usually zinc. The force of the battery
after it has been in action for a short time becomes considerably
weakened by what is termed the polarization of the negative elements
arising from the adherence of the hydrogen which is generated.
I construct my batteries of cast-iron plates or of what is known as
gas carbon; these plates are corrugated or ribbed. I obtain by this
means a greatly increased surface in the negative elements, and the ribs
part with the hydrogen more freely than flat surfaces, and consequently.
there is not so much polarization. In some cases I employ platina or
other suitable wire for the negative elements of the batteries, and I
thereby obtain a very large surface which is not so subject to polariza-
tion as flat plates. The wire used may be in the form of wire gauze or
wrapped upon a frame. I prefer surrounding the positive elements of
the battery entirely by the negative elements, so that the whole surface
of the positive elements exposed to the liquid may be active.
When 1 require the batteries to be very constant and to last a long
time I prefer exciting them with neutral salts, such as common table
salt, salammoniac, a solution of alum, or any other suitable salts, and
to reduce the local action I prefer the zinc plates to be amalgamated.
The battery troughs are closed on the top and made water-tight by
bolting down the lid with a layer of vulcanized india-rubber between or
by any other suitable means, a small pipe being inserted to allow any
gas which
may be generated to escape. The battery trough is mounted
on metal trunnions on which it can be revolved; these trunnions form
the battery connexions. The exciting fluid is only filled about halfway
up the plates. When the power of the battery becomes weakened from
the polarization of the plates, the battery trough is turned halfway round
and the other half of the plates become immersed, the surfaces of the
plate previously immersed are now exposed to the air and quickly
become depolarized. The shape of the troughs may be varied, they may
be made circular, and a constant motion communicated to them if
desired. When galvanic batteries are required to be put into action
only occasionally, the trough is made double the depth of the battery
plates. In one position the plates are out of the exciting liquid, in the
other they are immersed. This latter arrangement is very useful where
powerful currents are required for only a short time, as the plates are
entirely out of the exciting fluid excepting during the time the batteries
are in active work.

page_text: When I require the motion of the electric apparatus to be maintained
at a uniform rate I construct a trainwork of wheels, which may be set
in motion either by a weight or by a spring, or by any other suitable way.
This trainwork sets in motion a electric governor, which consists of an
axle driven by the trainwork and having two arms working on a pin or
spring joint. The upper portion of the axle carries a disc of metal.
The axle is divided and joined together by an insulating substance, so
that the lower portion of the axle carrying the arms is not in electric
connection with the upper portion of the axle carrying the disc. When.
the trainwork is set in motion the two arms fly out by centrifugal force,
and when the speed attained is greater than that desired, the arms touch
the disc above them and close an electric circuit through an electro-
magnet, which may be made to retard the disc by the resistance which
magnetism opposes to the motion of a diamagnetic metal, or by the
attraction of a lever against the periphery of the disc.
The enclosing the battery in a water-tight trough and mounting it on
trunnions so that it can be revolved admits of other useful applications
besides those herein-before described; one useful application is to that of
electrotyping, the metal deposited in a revolving trough is smoother and
more uniform than that deposited in a stationary trough, the tendency
for bubbles of hydrogen to be formed being prevented and the strength
of the solution being maintained more uniform throughout. When I
use the battery for this purpose I make the decomposition cell in which
the metal is deposited by preference a part of the battery trough, or it
may be attached to it so that it revolves with the battery. I prefer,
however, sometimes to make the mould in which the metal is deposited
revolve in the opposite direction to that of the decomposition trough,
which can be readily done by suitable gearing. It is sometimes more
convenient for the decomposition trough not to be attached to the battery
and motion communicated only to the mould on which the metal is
being deposited.
The method described of maintaining the temperature uniform for the
manufacture of differential galvanometers and resistance coils may be
also usefully applied in nearly all cases where a uniform temperature is
desirable.
And in order that my said Invention may be most fully understood
and carried into effect I will proceed to describe the Drawings hereunto
annexed.

page_text: DESCRIPTION OF THE DRAWINGS.
Figure 1 represents a back view of the commutator for "Varley's
universal needle telegraph instruments; Figure 2 represents a side
view of the axle.
"
A, A, A, A, is a board upon which the springs and contact pieces are
planted, and which is bolted to the inside of the iron case by means of
the bolts A', A', A'; B, B', is the axle working in the bush which forms
part of the iron case, which is indicated by the dotted lines in Figure 2.
B", B, B, is the transverse piece; b is a flat projection upon which
the tweezer springs act; C, C, are the two projections between which
the upper end of the transverse piece B" works, and which limit the
motion of the axle; these projections are usually in one solid piece with
the case.
1 and 2 are Numbers "d" and "2" springs atached to the
board A, A, A, A, by means of the cocks D, D'; E, E', are blocks of
metal attached to Numbers "1" and "2" springs, are usually made
of hard bell metal; 3 and 4 are Numbers 3" and * 4" springs
attached to the board by the long cock c, e, (which is connected to one
pole of the galvanic battery, usually the copper pole), the middle portion
of this cock is represented removed, to enable the upper end of the
transverse piece to be seen; 5 and 6 are two contact pieces, and are
connected to one pole of the galvanic battery, usually the zinc pole.
F, F, are the tweezer springs attached to the cock F, which is bolted
to the case of the instrument. G, G, are the stops against which
Nos. 3" and 4" springs rest. b' is the pin which passes through the
iron case into the upper end of the transverse piece B", by which the
circuit is kept permanently closed when desired; b is a flange upon the
pin working in a chamber in the iron case which allows suflicient play
for the withdrawal of the pin from the transverse piece, but prevents it
being wholly withdrawn.
Figure 3 represents a top view of the commutator in which two levers
or keys are used.
.
Figure 4 is a side view of the same. H, H, H", H, are the two
levers, the axles of which work in the blocks H1, H2; h, h', are pieces
of insulating material attached to the back ends" of the levers; I, I'
are the "back end springs;" J is the bridge working in the blocks K, K,
and which can be twisted round by the milled nut J'; j, j are the
circular contact pieces against which the levers H, H", rest; L, L', are

page_text: the "
upper springs;" M, M, is the front contact; N, N', are two terminals
connected to the levers H, H"; Z and Y are the two battery terminals,
one of which is connected to the front contact, the other to the upper
springs."
Figure 5 represents the improved construction of differential galvano-
meters. O, O', represents the two sets of convolutions of insulated wire
forming the coils of the differential galvanometer; P, P, P", P, are
springs connected to the extremities of the coil wires; P, p', p", p, are
the contact pieces against which the springs P, P', P", P, press; Qis
the commutator barrel; Q1, Q2, are the two eccentrics attached to the
commutator barrel; R is the key or contact maker. The commutator
barrel is connected to the contact maker R; the contact pieces p, p",
are connected together by a metallic connection; p' and p are also
connected together in the same way. When No. 1" eccentric Q 1 is
turned downwards, and the contact maker; R depressed, a positive current
flows from the battery S through eccentric Q' to the galvanometer coils,
through which the current divides, passing through coil O to the line
wire, and through coil O to the resistance coils, and then to the earth.
On turning eccentric Q 2 downwards, and depressing the contact maker R
as before, the electric current divides itself through the coils of the
galvanometer, but passes in this case through the coil O' to the line
circuit, and through coil O. to the resistance coils. When the com-
mutator barrel is turned midway, in which position the springs P, P,
", press against their respective contact pieces, the two coil wires
can be tested to see if there be any leakings between them by temporarily
insulating the extremities of one of the coils by placing any insulating
substance between the springs and the contact pieces. The two sets of
convolutions forming the differential galvanometer will then be separated
from one another, and can be tested for insulation.
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,
Figures 6 and 7 represent the improved construction of commutators
for closing the electric circuit through resistance coils.
Figure 6 is a top view; Figure 7 is a sectional view in elevation;
T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, are the segments
to which the extremities of the insulated wire forming the resistance
coils are attached; U, U, U, U, are the bobbins on which the coils are
wrapped; V, VI, are the two metallic arms; W, W, W, is a tube of in-
sulating material separating the metallic arms from one another; X is
a spiral spring inside the insulating tube W which presses upon the

page_text: flange V 1, forcing the arm V on to the segments T; X 1 is another spiral
spring working in the chamber Y, Y, and pressing upon the flange V 2,
and forcing the arm V upon the segments T. Z is a terminal connected
by a metal connection with the wire rope Z 1 attached to the arm V,
forming a flexible metallic connection. Z is a second terminal con-
nected to the wire rope Z, forming a flexible metallic connection with V¹.
When the circuit is closed the current passes from Z to the arm V to
the segment on which it rests through the resistance coil or coils in the
circuit to the segment on which the arm V' is resting through the
arm V to the terminal Z.
Figures 8, 9, 10, shew the method of maintaining a uniform tempera-
ture. Figure 8 shews the construction of the boiler in which the water,
is heated. Figures 9 and 10 shew the construction of the mercurial
valves, and the way in which they are adjusted to turn on or cut off the
supply of gas at any desired temperature. A 4, A 4, A 4, A 4, are the
two metal plates coated with lead or pewter; a, a, a, a, a, a, represent
the lead or composition pipes which pass through and are rivetted to
the plates A 4, A 4, A 4, A 4; B 4, B 4, B 4, B 4, is the metal covering
surrounding the pipes, and soldered to the upper and lower plates;
C4, C4, C4, C4, is the water casing in which the gas burner is placed,
and which is attached to and forms part of the boiler A 4, A 4, A 4, A 4;
D 4 is the pipe through which the heated water passes to the hot-water
system surrounding the chamber which is to be heated; E 4 is the pipe
by which the cooler water re-enters the boiler; F 4, F. 4, F 4, F 4, are
the gutters which collect the water produced by the combustion; G 4 is
the pipe through which the water passes from the gutters; H is the
chimney pipe.
Figure 9 shews the construction of the mercurial valve when the
expansion and contraction of spirits of wine, or other fluid is made to
open or close the mercurial valve turning on or cutting off the supply
in accordance with the temperature of the chamber to be heated.
of
gas
Figure 9 is a sectional view of the mercurial valve and heat regulator;
14 is a chamber which is filled part of the way up with mercury, and
the remaining part with spirits of wine or other suitable fluid, this
chamber is usually made of a piece of iron gas barrel. A piece of
iron 14 is welded into the upper portion of the chamber, this piece of
iron has a hole drilled through it but not of the same diameter through-
out, the lower portion of the hole being contracted, this hole is tapped

page_text: throughout its large diameter, and a capstan headed screw J 4 screws
into it, when this screw is screwed in tightly its lower end jams into the
contracted portion of the hole making a tight joint; K 4 is a cylinder
usually made of cast iron and is constructed with a cavity K' 4 in its
centre, this cavity is contracted somewhat in the upper portion, and is
partially filled with mercury, the lower portion of the chamber 14
communicates with the cavity K' 4; L' is an adjusting screw working
through a stuffing box into the cavity K 4; M 4 is another screw, which
when screwed up tightly makes a jam joint and prevents the mercury in
the cavity from running out, but when it is unscrewed it opens a passage
from the cavity to the outside; N 4 is a circular piece of cast iron fitting
on to the top of K 4 and is recessed out at the bottom, forming a central
space between it and K 4; the upper portion of N 4 is also recessed to
enable it to hold mercury. When this apparatus is in use the gas passes
through the pipe O 4 which is fitted into the circular piece of iron N 4,
and projects beyond and enters a little way into the contracted portion
of the cavity K' 4, the gas then passes in the space between the pipe and
the contracted portion of the cavity into the circular space of N 4 into
the pipe P 4, which is fitted into N 4, and through this pipe to the gas
burner. When the spirits of wine and mercury in the chamber 14
become expanded, consequent on the temperature being raised, it forces
up the mercury in the cavity K' 4 and closes the mouth of the pipe O 4,
cutting off the supply of gas. When the temperature falls the spirits of
wine contracts, and the mercury falls below the mouth of the pipe O 4,
and the gas is again turned on and relighted by a small independent
burner kept continually burning when the apparatus is at work. The
apparatus is adjusted to cut off or turn on the supply of gas at any
desired temperature by putting more mercury into the cavity K 4 or
taking it out as the case may require, and this done by means of the
jam screw M 4, which when unscrewed allows the mercury to run out,
and by means of the jam screw Q 4, which when unscrewed allows
mercury to be poured in through N 4 into the cavity K' 4, by this means
the apparatus is roughtly adjusted; the exact adjustment is obtained by
screwing the adjusting screw L 4 in or out as may be necessary.
Figure 10 shews the method I adopt of making the expansion of
metal open or close the mercurial valve by closing an electric circuit;
R 4 is a compound bar which may be constructed of steel and brass
attached to each other, or of any two metals which expand unequally;

page_text: this compound metallic bar works on a pivot which works in pivot holes
in the standard S 4, or it may work on knife edges; T 4 is an adjusting
weight and can be screwed up or down a screw attached to the lower
end of the bar R 4; U 4 is a contact screw which works through a
standard U¹ 4, and can be screwed farther from or nearer to the bar R 4;
V 4 is the galvanic battery; W 4 is a chamber attached to a lever which
works upon a joint W1 4; X 4 is a balance weight attached to the lever
on the other side of the joint W 4; Y 4 is a screw top which prevents
the lever falling below a determined fixed distance; % 4 is an electro-
magnet; A 5 is a pipe passing through the centre of a chamber B 5;
C 5 is a pipe leading out of this chamber.
The modus operandi is as follows:-Sufficient mercury is poured
into W 4 to cover the mouth of the chamber B 5 but not enough to
cover the mouth of the pipe A 5 forming a liquid joint. The gas passes
through A 5 into the chamber B 5 out of the pipe C5 to the gas
burner which heats the boiler, one pole of the battery is connected to
the standard S 4 and the other pole to one end of the electro-magnet,
the other end of the electro-magnet is connected with the standard U 4.
When the temperature becomes raised the compound bar from the
unequal expansion becomes bent and falls over by gravity making contact
with U 4, the electric circuit is now completed the current passing from
the copper pole through the electro-magnet to U 4 through R 4 to S 4
and thence to the zinc pole, the electro-magnet being rendered active
attracts the lever carrying the chamber W 4, and the mercury of this
chamber closes the mouth of the pipe A 5 and cuts off the supply of
gas by screwing the adjusting weight T 4 up or down, and by screwing
the contact screw U 4 nearer to or farther from the compound bar R 4,
the apparatus can be arranged to turn on or cut off the supply of gas
at any desired temperature.
Figure 11 is a sectional view of the Leyden arrangement.
D 5, D 5,
D 5, D 5, is an open glass tube; E 5, E 5, is the inner coating which is
made of thin sheet brass or copper. F5, F 5, is a brass or copper ring
usually made by spinning thin metal over a piece of wood, and is soldered
to the inner coating E 5. G 5, G 5, is a lining of tin foil on the inside
of the glass tube reaching to within about an inch and a half from the
bottom of the glass tube, H 5 is a pasteboard holder fitting on to the
outside of the tube and containing the cushion I 5, 1 5.
K
5 is a long

page_text: Figure 12 shews the inner coating and brass ring separate.
L 5 is
the piece of wood over which the metal ring is spun and which is
cemented into the upper end of the glass tube by any suitable cement..
Figure 13 shews the improved method of casting bells.
M 5 is the
mould into which the molten metal is poured. N 5 is the die which is
forced in either by a fly press, or by any other suitable means.
Figures 14 and 15 shew the construction of the electric alarums;
Figure 14 is a front view, Figure 15 a side view. 05 is a cast-iron
frame to which the various portions of the alarum are attached. 0¹5 is a
projecting block of iron forming part of the frame into which three soft
iron cores indicated by the dotted lines fit. These soft iron cores are
surrounded by convolutions of insulated wire forming electro-magnets.
The middle core serves for two pairs of electro-magnets; Q 5, R 5, re-
present the two sets of convolutions surrounding the central soft iron
core. P 5 and P¹5 represent the convolutions of insulated wire sur-
rounding the two other soft iron cores. S 5, S'5, is the armature working
on an axle in its centre. T 5 represents one of the cocks in which the
axle works, and which is usually mounted on the top flange of the,
electro-magnet Q 5. U 5, U¹5, are the two hammers which play upon
the two bells V 5, V15, when the alarum is active. W 5 is the magnetic
make and break, and may he either a piece of soft iron or a permanent
magnet, and works upon an axle, one end of the make and break works
between the contact screws X 5, X¹5, the other end is forked. The armature
lever to which the hammer U15 is attached plays between this fork S 6;
N 6, is a permanent magnet with projecting arms at the upper end, the
contact screws X 5, X¹5, work through these projecting arms, but one of
them is insulated from the permanent magnet, and in some cases both
ile contact screws are insulated. Y 5, Y15, are soft iron bars working
on axles, and which hang perpendicularly by gravity and prevent the
bells being rung by any oscillation. When the electric current is closed
through the alarums the current passes from the magnetic make and
break to one of the contact screws, say X¹5, through the electro-magnets
P 5 and R 5 rendering this pair of electro-magnets active, the soft iron
bar Y 5 is attached towards P 5 as represented in Figure 14. The
armature is attracted down and the bell V 5 struck, the lever attached

page_text: to the other end of the armature in its passage upwards strikes the fork
of the magnetic make and break, knocking it away from the upper
contact screw X'5 on to X 5 to which it adheres by magnetic attraction,
the circuit is now closed through the other pair of electro-magnets Q 5,
P5, and the armature is attracted down on the right hand side and the
bell struck. The hammer lever in its descent strikes the fork of
the magnetic make and break knocking it away from X 5 to X5 where
it adheres by magnetic attraction and the circuit becomes closed through
the other pair of electro-magnets, in this way the alarum continues to
ring so long as the circuit is closed. In Figure 15 the magnetic make
and break is represented midway between the contact screws, but in
practice it is always in contact either with the one or the other, being
attracted and held over by magnetic attraction, the contact screws are
made of iron or steel tipped with platina or other non-oxidizable metal at
the points of contact.
Figure 16 represents a relay which may be usefully employed in some
cases in connection with the alarum to put a local battery in circuit
with the alarum. Z 5, Z 5, Z 5, is a permanent magnet embracing a
hollow coil A 6, A 6; B 6, B'6, is a lever of soft iron working on an
axle 6; C 6, C6, are two soft iron screws, and may be regarded as
prolongations of the poles of the permanent magnet; D 6 is a contact
screw; D'6 is a screw stop. When a current is sent through the coil
the lever B 6, B'6 becomes magnetic, and is attracted over to one end
of the prolongations of the poles C'6 making contact with D6, and,
closing a local circuit in the usual way, and which will remain closed
until the lever has been removed from the contact piece.
Figures 17, 18, and 19 shew my improved method of constructing
coils, the magnetic needles of which are not affected by the passage of
high tension electricity through the coils. Figure 17 is a front view
with the front plate to which the work is attached removed; Figure 18
is a back view; Figure 19 is a side view. E 6, E6, E6, E6, is a
circle of soft iron divided into four segments and connected by soft iron
arms to the four small electro-magnets F 6, F6, F6, F6; G 6, G 6, is
the permanent magnet attached to the electro-magnets, and which
induces magnetism in them; H 6 is a soft iron needle working on an
axle in the centre of the divided circle of soft iron; I 6, I 6, I 6, I 6, is
the plate of non-magnetic metal to which the electro-magnets are
attached.

page_text: Having now described the nature of the said Invention, and the
manner in which the same is to be performed, I would have it under-
stood that I do not confine myself to the precise details herein shewn
and described, but what I do claim is,
1st. The general construction of the commutator which enables me to
make the metal blocks or anvils which limit the motion of the axle of
the telegraph instrument of the same piece of metal as that which forms
the bush through which the axle works, and the method of keeping the
circuit permanently closed when desired substantially as described in
Figures 1 and 2.
2nd. The making the bridge contacts of commutator circular so that
they can be twisted round to present fresh surfaces at the points of
contact, and the general construction and arrangement of the different
portions of the commutator, substantially as described in reference to
Figures 3 and 4.
3rd. The improved method of constructing differential galvanometers
and the arrangement of the connections, substantially as described in
reference to Figure 5.
4th. The method of constructing commutators for opening and closing
the electric circuit through resistance coils substantially as described in
reference to Figures 6 and 7.
5th. The method of constructing boilers to be heated by gas
substantially as described in reference to Figure 8.
6th. The method of constructing thermometrical valves or heat
regulators, substantially as described in reference Figures 9 and 10.
7th. The method of constructing the different parts of the Leyden
arrangement, substantially as described in reference to Figures 11
and 12.
Sth. The method of casting bells, substantially as described in
reference to Figure 13.
9th. The method of constructing electric alarums, substantially as
described in reference to Figures 14 and 15.
10th. The method of constructing coils, the magnetic needles of which
are not influenced by the passage of electric currents of high tension,
substantially as described in reference to Figures 17, 18, and 19.

page_text: 11th. The method of constructing galvanic batteries to lessen the
polarization of the negative elements, substantially as herein-before
described.
12th. Mounting galvanic batteries upon truunions which form the
connections and the constructing them so that they can be revolved or
tilted without spilling the electric fluid, substantially as herein-before
described.
13th. Giving motion to the decomposition trough or to the mould on
which metal is being electrically deposited so as to prevent the tendency.
to form hydrogen and so to obtain a smoother deposit, substantially as
herein-before described.
14th. The method of regulating the speed of telegraph apparatus,
substantially as herein-before described.
In witness whereof, I, the said Samuel Alfred Varley, have here-
unto set my hand and seal, this Nineteenth day of March, in
the year of our Lord One thousand eight hundred and seventy.
SAMUEL ALFRED VARLEY. (L.S.)