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·The oldest known instrument used to measure time is called a gnomon. It is simply some type of vertical post - a stick, column, or stone - that casts a shadow. When the shadow is at it's shortest length it is noon. Hour indicators were later added around the base resulting in the sundial:
Sundials are not always horizontal, they can be mounted vertically on a wall:
Solar based instruments don't have to be flat either, as shown by this invention called a polos:
Some instruments could be used in daylight or darkness. Below is an altimetric ring, or nocturlabium. It could be used to measured time at night. It was hung by the metal loop at the top. The user then adjusted the date on the ring dial and then looked through the center opening at the Pole Star which is the only relatively stationary star in the sky. Then the user pointed the indicator of the nocturlabium along the two outermost stars of Ursa Major (the Great Bear). Their positions determine the time shown on the instrument by the same indicator.
This is called a Shepherd's Clock:
Of course, if the sun is not visible than a solar instrument is useless. Other inventions shown below were based on regulated flow properties. Hour lamps (left) burned oil, and the markings on the side of the container showed the time that had passed according to the oil level remaining. Hour candles (right) gradually melt. Hourglasses (bottom) use sand.
Another way of telling time using flow is the clepsydra or water clock. The first versions were glorified buckets with a hole at the base. Internal markings became visible as the fluid drained which indicated the amount of time that had passed. The clepsydra became more sophisticated over the centuries. More intricate regulation methods spawned the basic principles of mechanical escapements. (technically, a mainspring "flows" it's stored energy to the gears of a watch or clock) Here are some shots of Su Song's "Shui Yun Yi Xiang Tai" astronomical waterclock. Competed in 1094, it was 40 ft tall and announced the time of day with bells, gongs, beating drums and written plaques.
images captured from the Science Channel
The earliest mechanical clocks were made in the 13th century and installed in church towers. The clock in Westminster Abbey dates to 1288, and records in St. Paul's Cathedral indicate there was a custodian responsible for keeping the clock working who was paid with bread & beer. Clocks were downsized to fit in private homes in the 14th century, and were simply miniature copies of tower clocks that were mounted securely on a wall and powered by a weight suspended on a rope. In the mid 15th century the mainspring became a viable replacement for the weight which led to portable clocks. The Dutch mathematician & scientist Christian Huygens designed and built the first clock with a pendulum around 1656/1657 based on Galileo's research from the late 1500's. In 1675 he invented the hairspring to match with the balance, which eventually became the regulator of mechanical watches.
Westminster Abbey's clock, and the most famous tower clock - Big Ben
Here's a pendulum-driven portable mantle clock from the 1890's:
....and it's mechanism:
Ships have a need for precise time keeping to aid in navigation. An inaccuracy of just one second can mean an error of almost 500 meters while at sea. Large rewards were offered to anyone who could develop an instrument that would function despite the pitching and rolling of a vessel underway. Abraham-Louis Breguet, Ferdinand Berthoud, and John Harrison were the pioneers of mechanical timepieces for ships. Harrison's version won Britain's prize for accuracy - equivalent to millions of dollars today! It kept time within 1/5 a second per day. Not bad for a self-taught watchmaker who was a carpenter by trade.
Here's a Berthoud marine chronometer from the 1700's:
and a more modern hyper-accurate Omega quartz Marine Chronometer from the 1970's:
Sundials are not always horizontal, they can be mounted vertically on a wall:
Solar based instruments don't have to be flat either, as shown by this invention called a polos:
Some instruments could be used in daylight or darkness. Below is an altimetric ring, or nocturlabium. It could be used to measured time at night. It was hung by the metal loop at the top. The user then adjusted the date on the ring dial and then looked through the center opening at the Pole Star which is the only relatively stationary star in the sky. Then the user pointed the indicator of the nocturlabium along the two outermost stars of Ursa Major (the Great Bear). Their positions determine the time shown on the instrument by the same indicator.
This is called a Shepherd's Clock:
Of course, if the sun is not visible than a solar instrument is useless. Other inventions shown below were based on regulated flow properties. Hour lamps (left) burned oil, and the markings on the side of the container showed the time that had passed according to the oil level remaining. Hour candles (right) gradually melt. Hourglasses (bottom) use sand.
Another way of telling time using flow is the clepsydra or water clock. The first versions were glorified buckets with a hole at the base. Internal markings became visible as the fluid drained which indicated the amount of time that had passed. The clepsydra became more sophisticated over the centuries. More intricate regulation methods spawned the basic principles of mechanical escapements. (technically, a mainspring "flows" it's stored energy to the gears of a watch or clock) Here are some shots of Su Song's "Shui Yun Yi Xiang Tai" astronomical waterclock. Competed in 1094, it was 40 ft tall and announced the time of day with bells, gongs, beating drums and written plaques.
images captured from the Science Channel
The earliest mechanical clocks were made in the 13th century and installed in church towers. The clock in Westminster Abbey dates to 1288, and records in St. Paul's Cathedral indicate there was a custodian responsible for keeping the clock working who was paid with bread & beer. Clocks were downsized to fit in private homes in the 14th century, and were simply miniature copies of tower clocks that were mounted securely on a wall and powered by a weight suspended on a rope. In the mid 15th century the mainspring became a viable replacement for the weight which led to portable clocks. The Dutch mathematician & scientist Christian Huygens designed and built the first clock with a pendulum around 1656/1657 based on Galileo's research from the late 1500's. In 1675 he invented the hairspring to match with the balance, which eventually became the regulator of mechanical watches.
Westminster Abbey's clock, and the most famous tower clock - Big Ben
Here's a pendulum-driven portable mantle clock from the 1890's:
....and it's mechanism:
Ships have a need for precise time keeping to aid in navigation. An inaccuracy of just one second can mean an error of almost 500 meters while at sea. Large rewards were offered to anyone who could develop an instrument that would function despite the pitching and rolling of a vessel underway. Abraham-Louis Breguet, Ferdinand Berthoud, and John Harrison were the pioneers of mechanical timepieces for ships. Harrison's version won Britain's prize for accuracy - equivalent to millions of dollars today! It kept time within 1/5 a second per day. Not bad for a self-taught watchmaker who was a carpenter by trade.
Here's a Berthoud marine chronometer from the 1700's:
and a more modern hyper-accurate Omega quartz Marine Chronometer from the 1970's:
