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History Of The SundialThe sundial or sun clock is considered to be the oldest known device for
the measurement of time and one of the most ancient scientific
instruments. It allows us to see our world in four dimensions – length,
width, height and time.
The operation of a sundial is based on the knowledge that the shadow of
an object will move from one side of the object to the other as the sun
"moves" across the sky during the day.
Historians are unsure who invented the sundial or exactly when it was
invented. It may have appeared in the Middle East or North Africa
perhaps invented by the Sumerians around 5000 to 6000 years ago.
Sundials are found in many ancient civilizations, such as Babylonian,
Greek, Egyptian and Roman. They are also common in the Far East
countries of China and Japan.
An early type of sundial called an obelisk, (a tall four sided monument), was built by Babylonians and Egyptians around 2500 BC. Obelisks were
placed in many locations in their cities.
The oldest known sundial, a smaller version of the obelisk, dates to
ancient Egypt from about 1500 BC. Time-keeping was so important to the
Egyptians that they even made portable versions of the sundial. “Shadow
clocks” were developed further by Chinese, Greek and Roman cultures.
An Egyptian sundial dating from around 800 BC is the earliest preserved
sundial we now have. It was made of a straight base of green schist with
a crosspiece on one end. The crosspiece was placed at the east end of
the base in the morning and the west end in the afternoon. The shadow of
the crosspiece on the base showed six time divisions.
Greek-style sundials were probably invented by the Chaldean priest and
author Berosus who lived around 340 BC. His sundial consisted of a block
with a half-circle bowl cut into it. The shadow of a small bead at the
center of the bowl moves around in a circle divided into twelve equal
parts. This type of sundial was popular with the Arabians and Romans.
Around 290 BC a sundial was captured from the Samnites and set up in
Rome. Another sundial was brought to Rome from Catanian by Valerius
Messala in 261 BC.
By 250 BC the Greeks such as Apollonius and Ptolemy used their knowledge
of geometry to construct sundials known as the hemicyclium and the
analemma, respectively. Around 100 BC the Tower of the Winds was
constructed in Athens, containing sundials facing the eight cardinal
compass points. In 1200 AD, Ab û al-Hasan wrote a treatise to introduce
the concept of equal hours.
The years between 1500 and 1800 AD are considered the “great age” of
sundials. Oronce Fine constructed a sundial made of ivory in 1524. Two
Italian astronomers, Giovanni Padovani and Giuseppe Biancani, published
treatises on how to construct a perfect sundial.
Stonehenge monument, constructed about 400 years ago, is a type of
sundial, which traces the sun’s movements for the entire year. In 1728
an astronomical observatory known as Jantar Mantar was built in Jaipur,
India.
The sundial was used to check the time on mechanical clocks until late
in the 1800s when mechanical clocks became inexpensive and accurate
enough to replace sundials as the timepiece of choice.
Alistair Charles on behalf of Courtyard Sundials. Courtyard Sundials are
purveyors and designers of a range of exclusive and high quality sundial
clocks.
by Alistair Charles
Alistair Charles on behalf of
Courtyard
http://www.courtyardsundials.co.uk Sundials. Courtyard Sundials are
purveyors and designers of a range of exclusive and high quality
http://www.courtyardsundials.co.uk sundial clocks.
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