A Brief History of Timepieces

The human race is obsessed with time. We keep clocks in our homes; our businesses. We wear watches, and check them frequently. We build time displays prominently into our electronic devices, and mount elaborate and ornate timepieces in the centre of our cities. Church bells chime out the hour while atomic clocks tick off the seconds by observing the movements made by the building blocks of the universe. Clocks have played a prominent role in the progress of civilization and several scientific breakthroughs from navigation to relativity. But how did this come about?

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In a hunter/gatherer or agrarian society it isn’t overwhelmingly difficult to keep track of time. The sun rises, sets, and reaches its zenith around the middle of the day. You can guestimate your way around the rest of the day when the only times you really need to worry about are meal times, and you let your stomach worry about those. But as society progresses and cities are built, mankind found a need to keep track of time more and more precisely. So they began to observe the heavens more precisely and invented the first clock, giving birth to what would become an obsession for scientists and inventors around the globe.

sundialThe first time keeping device was invented in about 1500 BC in Egypt. As you may have guessed already, the world’s first clock was a sundial. The sun, white moving from east to west, also moves around the sky. This changes the position and length of the shadows it casts throughout the day. By measuring and marking where the ends of the shadows fall you can divide the hours up into roughly even segments, and then measure the time by studying a sundial. Sundials had many drawbacks, however, the most obvious one being that they only worked when the sun shone.

The Egyptians were clever people, however. They are also responsible for inventing the water clock–an early precursor to the hourglass. Water ran out of a pot from a small hole at a fixed rate, and by the current height of the water you could determine how much time had passed since it was filled. They also invented a genius, but little-known method of telling time at night called Merkhets. By hanging plumb lines they created a local meridian and kept track of the hours of the night by tracking star movement across the meridian.

Candle ClockOther clocks invented over the next two thousand years include candle clocks and incense clocks. Like the water clock they burned at a presumably fixed rate, and you could measure the time by how far they had burned down. The hourglass was invented sometime around 150 BC, but disappeared from history until it resurfaced in 8th century France. Unlike the sundial, however, the hourglass is not a clock proper, but more of a timer that must be carefully maintained, and the number of turns it takes recorded by hand. They were principally used on ships and maintaining it was the duty of the watch who would ring out the hours whenever the sand ran through.

The first mechanical clocks were invented by…(drumroll please)…the Chinese. (You should have seen that one coming.) They had mechanical clocks as early as 725 AD. Europe didn’t catch up until the 14th century, and clock making didn’t really take off until the invention of the spring mechanism. Clocks rapidly caught on in popularity, mostly in Germany and France. They still didn’t resemble the clocks we are used to today, but humanity was beginning to keep a closer eye on the passage of time.

Galileo clockThe next great breakthrough didn’t come until 1650 with the invention of the pendulum clock. Coinciding with the age of scientific enlightenment, Galileo came up with the idea but Dutch mathematician Christiaan Huygens developed it into what today still exists as a grandfather or cuckoo clock. Suddenly timekeeping was all the rage, just in time to offer the solution to another thorny problem…Longitude.

Determining longitude became a serious issue in the 18th century. Latitude was easy–you can tell which hemisphere you are in, and how far from the equator, by measure the height of the sun in the sky. Longitude, however, measure how far east or wet you were, was infinitely more difficult. For sailors in the vast, featureless expanse of the ocean sailed by means of dead reckoning, and hoped no storm would throw them irredeemably off course. As sailing became more and more important to European culture, the ability to navigate became increasingly important, and in 1714 a prize was offered by the British government for a solution to the problem.

John Harrison Marine ChronometerThe prize was eventually awarded to John Harrison for invention of the Marine Chronometer–a time keeping device so small and so accurate it could be used to track the movement of the stars across the heavens. By comparing the position of the stars to an accurate time, a sailor could determine his longitude at sea and never be lost again.

The modern obsession with keeping accurate time down to the minute can traced back to the industrial revolution, when factory workers had to be on time for their shifts, so that production could be as effective as possible. The increase in the train infrastucture lead to a demand for accurate time tables, so that people could get to where they were going in a punctual manner. As the pace of human life increased so did the demand for ever more accurate clocks.

The drastic size of the American continent and the invention of the telegraph created a sudden interest in a local time other then your own, leading to the development of time zones. Precise scientific experiments created a demand for a measurement of time more precise than the clockwork that had been used so far. The use of the crystal quartz in clock-making came into use in the early 20th century. Nearly an order of magnitude more accurate than their mechanical counterparts, they quickly became the standard for nearly all time-keeping devices.

atomic-clockBut even this was not accurate enough. In 1949 the atomic clock was invented. Like the Quartz Clock it gets the time from measuring vibrations, but this time it measured the vibrations of atoms–the building blocks of the universe itself. The precision of these clocks lead to the development of the Global Positioning System (GPS)–a system of navigation so revolutionary that it is an eerie modern echo of the longitude problem solved three hundred years ago.

The atomic clock remains the most accurate clock invented to-date. It is capable of measuring not just seconds, but milliseconds, nanoseconds, and other fractions of seconds that are too unusual to be in common usage. The standardization of other measurements, such as the metre and volt also depend on the accurate measurement of a second, making the atomic clock one of the most important scientific tools in the world.

The history of timekeeping spans three and a half thousand years, and through it we can see the march of human progress. As our understanding of the nature of time increases, so does our dependence on accurate timekeeping. How many of our scientific advancements would never have come to be if we were still reliant on clockwork and sunlight?

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