Daniel Webster defines time as a
period or an interval between two events during which something
exists, happens or acts. These events may be measurable in
centuries, days or microseconds, provided one has the
appropriate tool to conduct the measurement.
The clock is such an instrument with
which to measure time in hours, minutes and seconds; modern
calendar watches also display the date. But man was not always
so lucky as to find a new timepiece under the Christmas tree or
to receive one as a token of appreciation for umpteen years of
faithful service from his employer. No, time measuring devices
had to be developed and constantly improved and updated by
successive inventions, until the accuracy of a modern atomic
clock was established to be a loss or gain of one second in 20
million years!!
Primitive man was able to tell time in nature. Light and
darkness gave him the time of day; a new moon the beginning of a
month and the change in the seasons with their varying daylight
hours gave him the rhythm of the year. With no flight to catch
and no doctor’s appointment to keep, that was sufficient for him
to carry out his daily routine. In time, his observations of the
movements of the heavenly bodies lead him to the invention of
the sundial, where the shadow of a stick in the ground moves in
accordance with the sun traversing across the sky. Obviously,
this ancient forerunner of an instrument that eventually put man
on a timed schedule was discarded from further development
because of its uselessness during the night and on overcast
days.
The old Egyptians advanced the development of time keeping
devices a step further, by introducing a water clock, called the
“Clepsydra.” In it, the water in a vessel is allowed to drip out
of an opening, lowering the water level in the vessel at a near
constant rate. The change in level, therefore, can be translated
into time elapsed. Not being dependent on time of day or weather
conditions, the water clock was definitely an improvement over
the sundial. And as long as accuracy was not an issue, dynasties
weren’t measured in seconds; the clepsydra must have served the
old pyramid builders well enough.
Searching through the literature failed to identify the inventor
of the first mechanical clock. Clocks seem to appear, however,
in a number of European countries in the Middle Ages, primarily
in monasteries, cathedrals and municipal buildings. Bulky as
these primitive devices were, they nevertheless revealed that
the clockmakers were on the right track to the development of an
“escapement” mechanism, that eventually provided the sought
after accuracy. The loss or gain of a quarter of an hour per day
was the best their inventive labor could produce.
The escapement is the function that allows clock mechanisms to
turn gears only a controlled amount in a specific amount of
time, for instance a degree of rotation per second. The “Foliot”
was the first escapement mechanism incorporated into mechanical
clocks in the Middle Ages. This mechanism was a set of weight
driven gears rotating by a certain amount, first in one
direction and then in the opposite, counterbalanced by a
horizontal cross arm to which weights were also attached.
Clocks with this early escapement mechanism were bulky due to
the elaborate construction and it is understandable why they
were primarily housed in clock towers. Greater accuracy was not
possible until the advent of the next generation of clocks,
namely the pendulum clock, which has survived the ages into our
time, the grandfather clock and the cuckoo clock are familiar
examples still found in many households.
The breakthrough came when a Dutch scientist named Christiaan
Huygens in 1656 realized that an accurate oscillatory function
is needed if his clock is to keep accurate time. He remembered
that Galilei had established the laws of the pendulum a hundred
years earlier. He had found that the period of the pendulum (one
complete swing) is dependent only on its length. By making the
pendulum part of the escapement mechanism Huygens found the
solution to a problem that had eluded contemporary clockmakers.
In a pendulum clock the energy required for movement of gears
and to overcome friction is typically supplied by a suspended
weight, which is attached to a gear train. However, the
gravitational force would cause the weight to descend rapidly
toward earth in accordance with the laws of free falling bodies,
thereby expending the potential energy needed to move the hour,
minute and second hands only a small amount at a time. Huygens
escapement consisted of the escapement gear and the pendulum,
rigidly attached to the anchor. The escapement gear, energized
by the suspended weight, gives the anchor a small boost by
virtue of the interconnecting teeth, causing the attached
pendulum to swing in one direction and the gear to advance a
small amount until, on the return swing of the pendulum, the
tooth on the opposite side of the anchor drops into a notch of
the escapement gear. That stops the movement momentarily. The
pendulum, now returning to its original position, moves the
anchor such that the locking tooth is released, receives another
nudge on the opposite side to sustain the action. Bingo, time
had come for man to schedule his activities.
An early attempt to reduce the size of a clock to make it even
portable goes back to 1510 when Peter Henlein, a Nuremberg
mechanic, was able to incorporate a steel spring as the energy
source of his “pocket watch.” Still somewhat bulky and lacking
the accuracy, which the pendulum clock later, achieved,
Henlein’s innovation nevertheless could run for forty hours
without rewinding. Stuffing the clockworks into a relatively
small container entitled Henlein a place on the list of
forgotten inventors.
But time does not stand still, nor
does the human mind rest in opening up new frontiers in science
and technology. Electricity, when it became available, steered
the inventive mind of clockmakers to use this newly found
inexhaustible pool of energy as the driving force for a new
generation of clocks. Early electric clocks were driven by a
synchronous motor that was in ”synch” with the frequency of the
applied alternating current. Other methods made use of the
magnetic force, created when an electric current flows through a
conductor, to move gears that allows the hour, minute and second
hands to move at the specific rate. A detailed description of
the various applications of electrical energy including
digitizing the clock face and miniaturizing the mechanism, so
women could wear petite, but hard to read wrist watches with
their fancy outfits, will not be attempted here, because of the
complicity.
Through research and development clocks and watches have
undergone changes in size and appearance as well as in
improvements in accuracy. But the principles of design features
have not changed since the early beginnings. Basic components, a
weight, spring or electric power is still needed for an energy
source, an oscillation device such as the pendulum or a quartz
crystal, as used in modern watches, is still needed, and
interconnecting gears to provide the timed movement of the
hands, is equally essential. Even the atomic clock, whose latest
version began operation for the National Institute of Standards
and Technology in 1999, requires an oscillator. In this case it
is the vibrating motion of the nucleus of an atom and its
orbiting electrons.
Life today without clocks and watches is unthinkable. We have
watches, probably several of them, a clock in every room and a
clock in the automobile. Coffee makers and other appliances come
with a timing device nowadays, needed or not. Some people pride
themselves in displaying an expensive watch, others do not. An
acquaintance bought a wristwatch to the tune of $ 24,000! It is
probably doubtful that in the routine of his daily life he needs
time told more accurately than the guy with a Mickey Mouse
watch.
The development of the clock is a fascinating story. It is
particularly amazing to note how clockmakers in the Middle Ages
have schemed and labored to come up with a usable timing device
when all parts had to be made by hand. From Peter Henlein’s
“pocket watch” and Huygen’s pendulum clock to the atomic clock
lie hundreds of years -a long time. According to Webster it was
a period in which something happened.
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2006 All content property of European Weekly unless where otherwise
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