wound possesses a metal cap in front, and a ratchet or toothed wheel at
the back end; between this cap and ratchet is a metal drum or tube
adapted to the width of the Frame. Passing through the drum is an axle
or barrel-arbor, on the back end of which the main or barrel-wheel is
fitted so as to allow the line which carries the weight to be wound
upon the barrel without moving the wheel, which latter is kept in place
by means of a cap or key pinned tight on the arbor. Upon the barrel
wheels are fitted clicks and springs, the former falling into the
toothed wheel or ratchet, and the latter keeping the clicks in place
while the clock is being wound up, for as the weights are wound up the
clicks prevent the barrel running back. At each end of the barrel arbor
is a pivot in brass bearings fitted in plumber block, and bolted on the
bed or frame with bolts and washers. Beyond the pivot on the front of
the arbor is a square to receive the winder. The uprights or small
frames for carrying the going-train contain the following; first, there
is an arbor across the frame at the back of which is a pinion working in
the teeth of the barrel-wheel; at the other end of the arbor is the
centre-wheel with teeth cut in it, and above this wheel is another
pinion running into it with a wheel at the other end, termed the third
wheel and pinion. The escape-pinion runs into the third wheel; on this
arbor is fitted the escape-wheel, which has very fine teeth cut in it.
Above the escape-wheel is an arbor termed the verge arbor, to which are
fitted the pallet arms. The pallet bits or pads working in the
escape-wheel teeth are of hardened steel polished. At the back end of
the verge arbor is fitted the crutch which connects the escapement and
the pendulum rod. The escapement is that called the dead-beat or lever
escapement, found to be the best for time-keeping, and least likely to
get out of order. Upon the set-hand arbor, used for setting the hands on
the dial to time, are two springs or keys to keep in place a wheel
fitted loosely on the arbor, and working in the teeth of the
centre-wheel. The hands are set by means of the set key which fits on
the end of the arbor in front. At the back end of the same arbor is a
joint by means of which an iron rod connects the clock to the dial, and
works the outside hands. The whole of the arbors are turned with
suitable pivots into brass bearings screwed into the uprights, and all
bolted to the bed or frame by stout bolts and washers. On the front
upright is fitted an index or set-dial by which to set the outside
hands, and two wheels and pinions, termed the motion or dial-work,
fitted on sockets and working on iron studs which are screwed into the
upright. Upon the largest wheel, known as the hour-wheel, is fixed a
snail having twelve steps in it for regulating the strokes to be given
at the different hours. The striking-train consists of a barrel similar
to the going-train, only that it has a camm or toothed-wheel fitted on
the back of the barrel-wheel for the purpose of raising the hammer
which strikes the bell, a lever being used called the hammer-tail. This
barrel is fitted into bearings in plummer-block, and bolted on frame.
The train of wheels and pinions fitted in arbors, and working in brass
bearings, consists of,--the pallet pinion fitted tight in the pallet
arbor and working in the teeth of the barrel-wheel; at the front end of
this arbor is a pallet of steel working in the teeth of the rack (see
next illustration), and gathering it up as the blows of the hammer
striking the hours are given on the barrel. Above the pallet arbor is a
pinion running into the teeth of the pallet wheel and termed the
fly-pinion, as it is used for regulating the blows or strokes. Fans are
attached to the fly-pinion to assist in regulating the striking,--the
intervals between the strokes being thus made longer or shorter as
desired. Fitted to the fly-frame is a ratchet with two clicks and
springs, these being used to prevent the train being stopped too
suddenly, and the damage likely to arise therefrom. At the right-hand
side of the clock frame is an arbor to carry the work for the
maintaining power, by means of which work the clock is kept going even
while it is being wound up, and injury to the escapement is at the same
time prevented. But for this maintaining power during the winding-up,
whilst the pendulum is vibrating to and fro, the pallets are liable to
catch the teeth of the wheel, and these are so fine as to be readily
injured. As properly fixed the clock cannot be wound up unless this
maintaining power is put in action by means of a lever passing in front
of the barrel-square, so that the winder cannot be put on the square
until the lever is raised and puts this power in action. The repeating
work for the striking-train is fitted on brass sockets working on
wrought-iron studs screwed into the front upright, and consists of the
Rack-hook, Warning, Locking, and Lifting pieces. The Rack is a portion
of a circle with a number of half-circular teeth cut on its edge; at the
end of the Rack is the Rack-arm fitted with a spring having a nib or pin
in it, which nib or pin falls upon the steps of the before-mentioned
hour-snail, and thus the different strokes are given at the hours; as
the nib falls nearer the centre the rack drops a greater number of
teeth. The Rack-hook is placed above the rack to catch the rack as it is
gathered up by the gathering pallets, and when the proper number of
strokes has been given this hook falls into a deep tooth, and then, by
means of a locking-piece attached to it, causes the train to be locked
with the stop-piece on the fly-pinion arbor, this latter piece forming
part of both the locking and warning work. The lifting-piece lifts the
rack-hook out of the deep tooth in the rack and locking, by means of a
snail or eccentric fitted on the set-hand arbor. On this lifting-piece
is also a piece for the warning, fitted on a small stud. The pendulum
rod has a brass top, and some adjusting work with a steel suspension
spring set in brass, by means of which the clock can be put in beat with
great exactness, there being no necessity with this adjustment to bend
the crutch as heretofore, for the crutch on the verge arbor has a pin
screwed into it which communicates the escapement to the adjusting work
or pendulum, and keeps it in motion. At the bottom of the pendulum rod
is an iron screw and nut by means of which the pendulum bob is raised
or lowered, and the clock made to go faster or slower. The motion or
dial work for driving the hands are outside at the back of the dials,
and consist of two wheels and pinions working in one another, the larger
of the two being fitted to a socket and tube. At the other end of this
tube is another socket for the hour hand to be fixed to; and through
this tube passes another iron rod, at one end of which rod is fitted one
of the pinions and the minute hand, the other wheel and pinion being
fitted on a socket worked upon a stud in a cock bolted on a bar called
the dial bar. If the clock has to drive more than one pair of dial
hands, wheels called bevelled or angle wheels are used, which may be cut
to suit any angle, so it will not matter how far off the dials may be
fitted, or how many they may be, so long as the proper expansion and
universal joints are fitted to them. The Hammer-work consists of an iron
frame with an arbor pivoted into brass bearings, and upon this arbor is
fitted a lever, one end of the lever holding the hammer-head, and the
other end raising the hammer. The lifting of the hammer is done by means
of a wire from the hammer-tail previously mentioned. There is also a
steel spring attached to the lever to prevent the hammer chattering on
the bell.
+----------------------------------------------------------------------+
| [Illustration: The Rack.] |
| |
| [Illustration: Pendulum Rod.] |
| |
| [Illustration: Quarter or Chime Clock.] |
+----------------------------------------------------------------------+
QUARTER or CHIME CLOCKS differ from the above only in having another
barrel and train of wheels to provide the extra power for such
striking and chiming.
+----------------------------------------------------------------------+
| [Illustration: GAS WHEEL FOR ILLUMINATED DIALS.] |
+----------------------------------------------------------------------+
In instances where it is requisite that the clock face should be
visible at a great distance, it is necessary that the dial should be
made of semi-transparent glass and be illuminated by gas, which is
usually turned as low as possible by day and turned on at night by
means of the 24-hour wheel, as shown in the annexed illustration, the
time for the turning on being regulated by the man in charge of the
clock, who takes out or screws in the pins placed in the rim for that
purpose.
+----------------------------------------------------------------------+
| [Illustration: NEST OF BEVELLED WHEELS FOR FOUR DIALS.] |
+----------------------------------------------------------------------+
These wheels should be rather large, inasmuch as they have to carry
the hands moving upon the face of the dial. The size of these wheels
varies of course with the size of the clock, but they are seldom less
than five inches and are generally from seven to nine inches wide.
HAMMER AND BELL.
The next engraving exhibits the relative positions of hammer and bell
in a turret clock,--the hammer being fixed at right angles to the
swing of the bell, so that the blow of the hammer should not drive the
bell out of reach of its next blow, and this position least
interfering with the ringing of the bell, when the bell is required to
be rung. The hammer spring, as shown, is sometimes so adjusted as to
allow of the hammer being brought nearer or further from the bell.
+----------------------------------------------------------------------+
| [Illustration: Hammer and Bell.] |
+----------------------------------------------------------------------+
THE GREAT CLOCKS OF THE INTERNATIONAL EXHIBITION OF 1862.
BENSON'S GREAT CLOCK.
+----------------------------------------------------------------------+
| [Illustration: Benson's Great Clock.--The Exterior.] |
| |
| [Illustration: Benson's Great Clock.--The Movement.] |
+----------------------------------------------------------------------+
The movement of this clock, next to that at Westminster, is the largest
in the world, and, in point of quality of material and finish of
workmanship, it is unequalled by any. The three main wheels are each two
feet in diameter, and cast in the solid, of the very finest gun-metal,
the teeth being afterwards cut by an engine made expressly for that
purpose. The frame is of the best wrought-iron planed to a smooth
surface, and by means of a contrivance, known to engineers as plumber
blocks, any part of the mechanism may be removed without disturbing the
remainder. The pendulum, which is self-compensating, is over 15 feet
long, and vibrates or beats once in two seconds. The quarter chimes,
which are struck on four bells, are a modification of those of S. Mary,
Cambridge.
The great weights necessary to drive so large a clock, and which by
the friction they would cause might prejudicially influence its
performance, are in this case not allowed to act directly upon the
pendulum, but are made to wind up a small auxiliary weight once every
half-minute, and this weight imparts an exactly uniform impulse to the
pendulum at each vibration. This arrangement, which is called the
_remontoir_, is supplemented in this clock by a double lever
escapement of a novel kind, in connection with that known as Graham's
Dead Beat.
A CALENDAR AND WIND-DIAL
are useful additions to some edifices. The CALENDAR indicates on
special circles of a large dial--by means of three separate hands--the
month of the year, the day of the month, and the day of the week. The
peculiarity of this invention is that it needs no correction for the
long and short months, nor even for the month of February, with its
occasional 29 days; as by means of a wheel cut for the successive
months in a period of four years, and which takes that time for a
single revolution, the calendar is rendered a perpetual one. The
mechanism which directs the pointers to the days of the week and of
the month is discharged, by the clock, each night at 12 o'clock, when
the levers shift the hands to their proper places on their several
dials. On the first of the month all three hands on the dial are moved
at the same instant.
The WIND-DIAL is lettered with the four cardinal points of the compass
and the 12 intermediates. The hand which points on the dial is
connected by rods and bevelled wheels with a vane at the top of the
house, placed 20 feet above the roof in order to be affected, not by
wind eddies, but by the true current of air. The connecting rods boxed
in the wall are broken at every eight feet with universal joints, and
hardened steel is used for all pivots and sockets. The dials are
generally made of semi-transparent ground glass and are lit by gas
after dark. In a set of Clock Calendars which I some time since
provided for His Grace the Duke of Portland, the clock showed the time
on four illuminated dials five feet nine inches in diameter, chiming
quarters, hours, &c. (the well-known Cambridge chimes) on bells of 12
cwt., repeating the hour after the 1st, 2nd, and 3rd quarters. The two
sides of an adjoining tower show a calendar similar to the one above
mentioned, with the addition of an extra circle on the dial to mark
the age of the moon and the equation of time, so that each dial has
four circles, besides the circle of the moon, shifted simultaneously
at 12 o'clock every night.
SUN-DIALS
(see illustration on following page) are chiefly used now to mark the
solar meridian or noon. Those which indicate other hours have a gnomon
with its edge parallel to the earth's axis and inclined to the horizon
at the angle corresponding to the latitude of the place in which the
dial is fixed.
CARILLON CHIMES.
+----------------------------------------------------------------------+
| [Illustration: Sun-Dial.] |
+----------------------------------------------------------------------+
These beautiful examples of _al fresco_ music, which have been hitherto
chiefly identified with Belgium, are now being produced in England with
perhaps even more pleasing and satisfactory musical effect. Carillons
attached to Church or Turret Clocks are being set up in various churches
and mansions in different parts of the kingdom, and it is not improbable
that the taste for such chimes may grow with the opportunity for hearing
them. As in musical clocks, the works for time-keeping and those for
chiming are entirely distinct, with the exception of the means by which
the clock at certain fixed intervals lets off the chiming machinery
after the striking is done. Chimes were much more popular years ago than
they have been until lately. The old-fashioned machinery used to be rude
enough, consisting chiefly of a large wooden barrel, stuck, like that of
a musical box, with pins. These pins pulled the hammers that struck upon
the bells, and the time was regulated by a rope coiled round one end of
the barrel driving two or three wheels connected with a fly-wheel. More
recent inventions have improved upon these conditions. The barrel is
sometimes of cast-iron instead of wood, with steel or brass pins fixed
in it to lift the hammers, and a very heavy weight is necessary to give
the motive power. Instead of the ordinary method of raising the hammers
and letting them fall by means of the pins on a chime barrel, the
hammers are immediately after use returned to their places in striking
position ready to be liberated by the pins on the chime barrel, and upon
being so liberated are prepared to strike again. The tunes to be played
upon these bells will of course be such as are adapted to the particular
number of bells in each case, and the cost of the entire chimes depends
upon the number and sizes of the bells so used,--varying with the
circumstances,--the size and capacity of the tower, and the difficulties
to be overcome in providing accommodation for the necessary bells,
weights, chime barrel, &c. In each instance, as with turret clocks, the
cost of the whole works depends to a great extent upon the cost of
fixing the machinery. The tones of the bells have to be carefully
provided for, as also the best position in which they can be heard at a
distance. With fourteen bells of different sizes almost any tune can be
played.
One was erected recently upon the new principle, of which the cost was
something under £5000, including 12 bells weighing from five to seven
cwt. each, clock, architect's charges, gas-fitting, and £1200 for
timber-trussing, floors, &c. The Carillon machine is let off by the
clock and plays seven times on the ringing peal of bells, but is
adapted to play twenty-eight tunes on fifteen bells. It is wound up
every morning and plays eight times in twenty-four hours, _i_. _e_.
once every three hours, giving the tune on each occasion three times,
and occupying about four minutes in doing so. At the expiration of the
24 hours the tune changes involuntarily, and of course with seven
tunes there is one for each day in the week. The Carillon machinery is
connected with the clock and set in motion thereby, by a lever which
at three hours' intervals dislodges a pin and allows the weights, 14
cwt. each, to act upon the machinery, the speed being easily
regulated, as in clockwork, by revolving vanes. The barrels are five
feet long, by one foot in diameter, and are studded with brass pins
like that of a musical box. When the bells are required to be rung, a
bar is turned down on the keys which prevents the motion of the
machinery for any length of time that the ringing is to be continued.
Notwithstanding that the twenty-six hammers weigh from 2 cwt. to 70lbs
each, it is possible that the tunes could be played by means of an
ivory keyboard, as in a church organ, and with almost as much ease and
facility.
Persons requiring to know the cost of a Church or Turret Clock should
furnish the Clockmaker with the following data:--
--------------------------------------------------------------
How many Dials? |
-------------------------------+------------------------------
Their Diameter? |
-------------------------------+------------------------------
Their Elevation, or distance |
from the ground? |
-------------------------------+------------------------------
If to be Illuminated? |
-------------------------------+------------------------------
Of what material is |
Dial to be? |
-------------------------------+------------------------------
Can the Movement be |
placed on a level with the |
centre of Dial, if not, how |
far above or below it? |
-------------------------------+------------------------------
Is the Clock to strike? |
if so, on what size or |
weight bell? |
-------------------------------+------------------------------
If to strike half-hours |
or quarters, or how many |
bells, and their sizes and |
weights? |
-------------------------------+------------------------------
What number of feet |
can be obtained for descent |
of weights? |
-------------------------------+------------------------------
What length of Pendulum |
will the building |
admit of, and is a compensating|
Pendulum required? |
--------------------------------------------------------------
A FEW DATES AND DETAILS FOR ALMANAC READERS.
The following data may be found useful in studying an Almanac.
The columns for SUNRISE AND SUNSET are nearly the same year after year
for any given place; for by the alteration of styles and the day
allowed at Leap Year the civil and astronomical year are almost
exactly the same; but the difference in latitude of different places
makes a London almanac useless for sunrise and sunset, say at
Edinburgh. The sun rises at each place to a greater height in June
than in December, but he is always at a less height in Edinburgh than
in London both in winter and summer, Edinburgh being farther than
London from the equator, where the sun is more immediately overhead.
The RISING AND SETTING OF THE MOON vary greatly day by day. The moon
is constantly moving eastward, and she is not moving in the same path
with the sun; the latitude and longitude of the observer's position,
the place of the moon in her orbit, the rapidity of her motion, and
other particulars, are to be taken into account in computing her
rising and setting.
The GOLDEN NUMBER is a term arising from the discovery that the sun
performs his annual course 19 times to the moon's 235. The golden
number is the number which any given year holds in the Lunar Cycle.
After the lapse of 19 years the new moons occur on the same days of
the same months as before. This discovery being esteemed by the Romans
to be highly important, they set up the rule for ascertaining the
number of the year in the Lunar Cycle in a tablet with letters of
gold, hence the term Golden Number. To find the year of the Lunar
Cycle add one to the present year, then divide by 19 and the remainder
will show the year of the Cycle.
The EPACT is the number of days which must be added to a lunar year to
complete a solar year. Twelve lunar months being nearly 11 days less
than the solar year, the new moons in one year falling 11 days earlier
than in the year preceding it, it becomes necessary on the fourth
year, when the difference would amount to 33 days, to take off 30 days
as an intercalary month, during which the moon has made a revolution,
and the three remaining would be the epact or 'addition,' which thus
continues to vary until the 19 years have expired, and the new moons
recur as before.
The SOLAR CYCLE is complete in 28 years, after which the days of the
month return to the same days of the week as before.
The DOMINICAL OR SUNDAY LETTER, as one of the first seven letters of
the alphabet, used to denote the days of the week, one of which must
of course fall on the Sunday throughout the year. Owing to Leap Year
their order every fourth year is disturbed, so that the Solar Cycle
must pass round before the letters can fall to the same days of the
week.
THE NUMBER OF DIRECTION. The Council of Nice having decided, A.D. 325,
that Easter Day is always the first Sunday after the full moon which
happens upon or next after the 21st of March, it follows that Easter
Day cannot take place earlier than the 22nd of March, or later than
the 25th of April. The number of Direction is that day of the 35, on
which Easter Sunday falls.
ROMAN INDICTION was a period of fifteen years, appointed by the
Emperor Constantine, A.D. 312, for the payment of certain taxes. It
was observed by the Greek and Roman Churches.
THE JULIAN PERIOD consists of 7980 years, produced by the
multiplication into each other of the Solar and Lunar Cycles and the
Roman Indiction, 28×19×15=7980. This period is reckoned from 709
before the Creation of the World, when the three Cycles are supposed
to have commenced together; the lapse of the entire period will be
A.D. 3267.
EQUATION OF TIME is the difference between the time as indicated by a
sun-dial, and that by a good clock. It is necessary because the sun,
the chief agent in measuring time, does not upon all days of the year
appear to move equally fast, inasmuch as an hour by a sun-dial,
correctly indicating the sun's motion, is sometimes longer, sometimes
shorter, than an hour by the clock, the hours of which are supposed to
be perfectly equal, although the sun's are not. The Equation of Time
shows how many minutes are to be added to, or subtracted from,
sun-dial time in order to show clock time. The same table of equation
will serve all over the world. [See following pages for Equation
Table.]
TRUE OR SOLAR TIME is that marked by the sun, and it is taken at the
moment when he has attained his greatest height above the
horizon,--such a moment being of course dependent upon the latitude of
the place of observation. The solar time by which our nautical
standard is fixed, is that of the meridian of Greenwich.
SIDEREAL TIME is that measured by the fixed stars, which are at such
an immense distance from the earth that the diurnal motion of the
earth brings these stars to the meridian at sufficiently regular
intervals. It is necessary, however, to remember when making
observations for sidereal time that these must be made from fixed or
twinkling stars, not from planets.
Of the various Eras from which time has been dated, the following are
the chief:--
A.M. _Anno Mundi._ The Year of the
World, dating from the Creation, according
to Jewish Calendar 5635
The Deluge, Era of, variously
reckoned 2348 to 3155 B.C.
The first Olympiad 776 B.C.
A.U.C. or _Anno Urbis Conditæ_, the year
of the building of Rome 753 B.C.
The Hegira, or Flight of Mahomet from
Mecca to Medina 622 A.D.
The Birth of Christ in the year of the
World 4004
The Jewish year 5635 commenced Sept.
12, 1874 A.D.
Table Colunm Headings
A. 3m.fa.45s.
B. 13m.fa.50s.
C. 12m.sl.36s.
D. 14m.fa. 1s.
E. 3m. sl. 0s.
F. 2m. sl.30s.
+---------------------------------------------------------------------+
| A TABLE OF THE EQUATION OF TIME, |
| For regulating Clocks and Watches for 1875. |
+-----+-----------+---------+----------+---------+---------+----------+
| Day | January |February | March | April | May | June |
+-----+-----------+---------+----------+---------+---------+----------+
| 1 | A | B | C | D | E | F |
| 3 | 4 41 | 14 4 | 12 11 | 3 25 | 3 14 | 2 12 |
| 5 | 5 36 | 14 16 | 11 45 | 2 49 | 3 26 | 1 51 |
| 7 | 6 29 | 14 24 | 11 16 | 2 14 | 3 35 | 1 30 |
| 9 | 7 20 | 14 29 | 10 47 | 1 41 | 3 43 | 1 7 |
| 11 | 8 9 | 14 30 | 10 16 | 1 8 | 3 48 | 0 44 |
| 13 | 8 55 | 14 29 | 9 43 | 0 36 | 3 51 | 0 19 |
| 15 | 9 39 | 14 24 | 9 9 | 0 5 | 3 51 | 0 fa. 6 |
| 17 |10 20 | 14 16 | 8 35 | 0 sl.24 | 3 50 | 0 31 |
| 19 |10 58 | 14 6 | 7 59 | 0 52 | 3 46 | 0 57 |
| 21 |11 33 | 13 53 | 7 23 | 1 18 | 3 40 | 1 23 |
| 23 |12 5 | 13 37 | 6 46 | 1 42 | 3 32 | 1 48 |
| 25 |12 34 | 13 19 | 6 9 | 2 5 | 3 22 | 2 14 |
| 27 |13 0 | 12 58 | 5 32 | 2 25 | 3 10 | 2 39 |
| 29 |13 22 | - - - | 4 55 | 2 44 | 2 55 | 3 4 |
| 31 |13 41 | - - - | 4 19 | - - - | 2 39 | - - - |
+-----+-----------+-----------+-----------+-----------+------------+--+