By
convention, a watch is said to be "simple" when it indicates hours,
minutes and seconds. Following this definition, a watch equipped with an
automatic mechanical movement, indicating only these functions, would
also be considered a "simple" watch. The same definition applies for a
very precise chronometer which indicates the time with a very high
degree of accuracy, even though this particular timepiece has been
subjected to a series of very stringent tests by the Chronometric
Observatory or another official chronometric testing facility. While
sometimes people confuse a chronometer and a chronograph, these two
timekeepers are not at all the same. Chronographs are defined below.
A
watch is said to be "complicated" when it indicates functions in
addition to the time. These may include optical readings using hands or
windows, or they may be acoustical in nature, using chimes or bells
A "grand complication" is a watch that contains at least three "complications", coming from each of the groups listed below.
Group 1: Complications using visual indications
a. Simple chronograph
b. Counter chronograph
c. Split-second flyback chronograph
d. Independent second hand chronograph
e. Jumping second hand chronograph
Group 2: Complications using visual astronomical indications
f. Simple calendar
g. Perpetual calendar
h. Moon phases
i. Time equation
Group 3: Complications using acoustical indications
j. Alarm
k. Quarter repeater
l. Half-quarter repeater
m. Five-minute repeater
n. Minute repeater
o. Passing strike
Definitions of complications by group
Group 1:
b. A counter chronograph has one or two additional subdials which count the minutes or hours starting from a given point in time.
c. A split-second flyback chronograph is
equipped with two superimposed center sweep second hands which can be
started together. The flyback hand may then be stopped to indicate the
reading at an intermediate time. When it is restarted, this hand
instantaneously "flies" back to the position of the first hand.
d. The independent second hand chronograph was
the precursor of the modern chronograph. It consisted of an independent
center or sweep second hand which could be started or stopped
independently of the normal time function but which could not be reset
to zero. This second hand advanced instantaneously then remained
immobile for nearly a second until it advanced again. It was driven by a
wheel and an independent spring which was wound separately by turning
the crown backwards. These watches have not been produced for many years
but are now highly prized by collectors.
e. The jumping second hand chronographused
an independent center sweep second hand which advanced continuously
rather than in jerks. In addition, this watch contained a small hand in a
special subdial at 6 o'clock which completed a revolution in one
second, jumping around in four or five successive quick movements. This
timepiece is no longer being made.
Group 2
Astronomical
functions were the first complications to be introduced into watches.
As early as the 16th Century, many years before the regulating spiral
was invented, exquisite pocket watches were equipped with date readings
and lunar phases.
f. Simple calendar watches
provide one, two or three functions, i.e. the date, often the day and
sometimes the month. All the months have 31 days so it is necessary to
manually correct the watch five times per year.
g. Perpetual calendar time-pieces
provide the three indications of their simple calendar cousins but also
automatically correct for the 30-day months as well as for February's
28 or 29 days.
h. The indicator for moon phases is
made up of a small specially shaped window in which the various phases
of the moon appear and disappear month by month. The most common
mechanism in use today is composed of a single wheel with 59 teeth
supporting two symmetrical moons. The wheel moves by one tooth per day
which gives a lunation of 291/2 days. Since the true lunation is 29
days, 12 hours, 44 minutes and 2.8 seconds, this gives a difference of
44 minutes and 2.8 seconds per lunation, or an advance of one day over a
period of 2 years and 235 days.
i. The time equationfunction
indicates the difference between the true local solar time and the
average artificial time. Our 24-hour day is an artificially designated
average solar day. The true solar time varies constantly in relation to
the average solar time, with the difference reaching more than 14
minutes around February 11 and 16 minutes around November 3. Only four
days per year are actually exactly 24 hours long. If a person wants to
set his watch using a sun dial, it is necessary to know this time
difference, or time equation, for each day of the year. In the past,
some watches were equipped with a fixed hand indicating the time
equation at noon each day. Other watches used an additional minute hand
carrying a sun which continuously showed the local true solar time.
Although no longer considered very useful, the time equation watches are
highly regarded by collectors.
Group 3
j.
The alarm function uses a very old mechanism whose fabrication was a
mandatory part of the training for master watchmakers. This acoustical
device can be programmed for a period of 12 or 24 hours.
The term repeater is
used for a watch equipped with a strike or chime capable of indicating
the hour on demand and repeating it as often as desired. The precision
of the time indicated depends on the type of repeater.
k. A quarter repeater function
strikes, on demand, the hours and quarter hours which have just passed.
It uses two bells of different tones, signaling each hour by a low tone
and each quarter hour by a higher tone followed by the lower one. For
example, at 3:40, the quarter repeater strikes three low tones, followed
by two series of high-then-low tones, giving bong, bong, bong, silence,
then bing-bong, bing-bong. By mentally adding 71 1/2 minutes to the
hour chimed, the largest deviation between the real time and the last
hour chimed will be 71 1/2 minutes (one-half of a quarter-hour). In our
example of 3:40, we can estimate the time to be 3:37.5, giving an error
of 2.5 minutes.
l. A half-quarter repeater function
strikes the hours and the quarter-hours but uses a high tone to signal
that the half-quarter has just passed. Using our example of 3:40, this
repeater would chime as follows: bong, bong, bong, silence, then
bing-bong, bing-bong, then bing to indicate that a half-quarter has just
passed.
m.
A five-minute repeater system strikes the hours with a low tone and
each five-minute interval with a higher tone. At 3:40, the mechanism
would chime bong, bong, bong, silence, then eight higher pitched bings.
n.
A minute repeater watch strikes the hours and quarters as does a
quarter-repeater. In addition, the minutes which exceed the last quarter
are signaled by a succession of rapid strikes on the higher toned bell.
For example, 12:59 would be given by 12 low tones, then three series of
high-low tones, followed by 14 rapid high tones.
o.
Watches with a passing strike function automatically signal the hours
and quarter-hours, with the hour repeated at each quarter. They also are
equipped with a device indicat-ing the hours and minutes on demand. The
energy for this function is provided by a powerful spring which is
wound at the same time as the watch. However, the number of demands is
limited. A silence position is also provided to discontinue the chime,
if desired.
Grand complications
It
is possible to make several types of grand complications. In general,
though, they are composed of a split-second flyback chronograph with
counters combined with a perpetual calendar (with or without moon
phases) and a repeater function, usually a minute repeater. There is,
however, nothing to prevent the addition of other elements not mentioned
here, such as a power-reserve indicator, thermometer, hygrometer or any
other device not yet imagined by today's watch-making geniuses.
Patek
Philippe pocket watch for James Ward Packard with a perpetual calendar,
solar hour, rising and setting sun times, moon phases and a rotating
disk of 500 stars representing the Ohio night sky, minute repeater with
three bells.
Question
Is it possible to attribute the creation and development of the first perpetual calendar watch to a specific watchmaker?
Ralph Edgar, Portland, Maine, USA
Most
watch historians give credit for this invention to Abraham-Louis
Breguet (1747-1823). Indeed, Breguet was a great watchmaker, having
invented and perfected a large number of ingenious devices. However, in
an article entitled "Horology" published in 1765 in the Encyclopedia by
Diderot and d'Alembert, there is a description of a watch equipped with a
perpetual calendar using a large disk on which are marked the months
and dates of a normal year. But this timepiece was made by a Swiss
watchmaker working in Paris named Ferdinand Berthoud (1727-1807). The
disk made a revolution in 365 days and the month of February contained
28 days. It was therefore necessary to let the watch stop on February 29
in order to maintain the time equation function which was also part of
Berthoud's system. The energy for his perpetual calendar was derived
from the daily winding of the watch.
Another
watchmaker also preceded Breguet in the development of the perpetual
calendar function. Jean-Antoine Lépine (1720-1814) was known as the
inventor of various devices which Breguet then later perfected. One
example, among others, is the anti-shock device which is often
mistakenly credited to Breguet. Lépine also invented calibers for
bridged watches. His ingenious system replaced the upper plate and
simplified assembly and the development of functions. It is still used
in all mechanical watches today.
Regarding
the perpetual calendar, one of Lépine's biographers wrote: "In 1770,
Lépine had the honor of presenting to Louis XV an astronomical repeater
watch equipped with a time equation function and perpetual calendar. The
former was used only in clocks and the latter was his own invention."
Unfortunately, the watch in question has disappeared and no other
perpetual calendar timepiece is known to have been made by him. Breguet
may have picked up this invention later, since, as some historians
speculate, he may have been a student of Lépine.