The days before clocks, History of time Guide
Introduction
Man has always strived for ways of measuring the passing of time. In the years before clocks people used a variety of things in order to tell the time.
These early forms of time keeping were often linked to religion and usually conducted by the church itself, who would then inform the public using audible signals like bells. But even in ancient or pagan civilisations, there were many ways to tell the time. Here are a few of the most popular.
Sun Clocks
As early as 3500 BC the Egyptians formally divided their day into parts which were something like our hours using obelisks. An obelisk is a slender, tapering, four-sided monument that casts long shadows according to the sun's position in the sky. These moving shadows formed a kind of sundial, enabling people to partition the day into morning and afternoon. Obelisks also showed the year's longest and shortest days when the shadow at noon was the shortest or longest of the year. A more portable and advanced obelisk was developed circa 1500 BC. As well as being lighter, this obelisk was able to divide day-time into 10 distinct parts (or hours) and even illustrate two twilight hours in the morning and evening.
The Egyptians also used their knowledge of time to develop astronomy tools. One of the world's oldest astronomy tools - the merkhet - was developed in Egypt circa 600 BC. The merkhet was made by taking the stem of a palm leaf and tying a string with a weight on the end to it. The vertical line produced by the weighted string was used to establish a North-South line (or meridian) by aligning a pair of merkhets exactly to the Pole Star. The merkhets were then used to tell time at night by determining when certain other stars crossed the meridian.
Water Clocks
Water clocks were among the earliest timekeepers that didn't depend on the observation of the sun.
One of the oldest was found in the tomb of the Egyptian pharaoh Amenhotep I, who was buried circa 1500 BC. Later named clepsydras (water thieves) by the Greeks, who began using them circa 325 BC, a clepsydras was a stone vessel with sloping sides that allowed water to drip at a nearly constant rate from a small hole near the bottom.
Other clepsydras were bowl-shaped containers designed to slowly fill with water coming in at a constant rate. Markings on the inside surfaces measured the passage of 'hours' as the water level reached them.
These clocks were used to determine hours at night, but may have been used in daylight as well. Remarkably, these water clocks were still in use in North Africa in the late 20th century.
More elaborate and impressive mechanized water clocks were developed between 100 BC and 500 AD by Greek and Roman horologists (or scholars of time keeping) and astronomers. The added complexity was aimed at making the flow more constant by regulating the pressure, and at providing fancier displays of the passage of time. Some water clocks rang bells and gongs; others opened doors and windows to show little figures of people, or moved pointers, dials, and astrological models of the universe.
But horologists in Asia were also busy developing their own methods of time keeping too. In China, a boom in mechanised astronomical clock-making began in 200 AD and continued for nearly a thousand years. In fact, third century Chinese clepsydras were even able to illustrate complicated astronomical phenomena. The Su Sung clock tower, named after its engineer Su Sung and standing over 30 feet tall, possessed a bronze power-driven viewing sphere for visitors as well as an automatically rotating celestial globe and five front panels with doors that permitted the viewing of changing mannequins which rang bells or gongs, and held tablets indicating the hour or other special times of the day.
Yet despite these elaborate mechanisms, however, the flow of water is very difficult to control accurately, and therefore a clock based on that flow could never achieve excellent accuracy. People were naturally led to other approaches.
The Church and Early mechanical clocks
No clocks survive from medieval Europe but various mentions in church records reveal some of the early history of the modern clock. Medieval religious institutions required clocks to measure and indicate the passing of time because, for many centuries, daily prayer and work schedules had to be strictly regulated.
This regulation was done by various types of time-telling and recording devices, such as water clocks, sundials and marked candles, probably used in combination. Important times and durations were broadcast by bells, rung either by hand or by some mechanical device such as a falling weight or rotating beater. These early clocks may not have used hands or dials, but rather they told the time with audible signals.
A new mechanism
The word clock (from the Latin word for bell) suggests that it was the sound of bells which also characterized the prototype mechanical clocks that appeared during the 13th century.
Between 1280 and 1320, there is an increase in the number of references to clocks in church records, and this indicates that a new type of clock mechanism had been devised.
Existing clock mechanisms that used water power were being adapted to take their driving power from two falling weights that drove the seconds. This mechanical release of weight operated like a pendulum and removed any dependence on the sun, or water, or candles, to drive the mechanism. It is this type of power driven mechanism that is the true foundation for modern clocks.
These new mechanical clocks were intended for two main purposes: for signaling and notification (e.g. the timing of services and public events), and for modelling the solar system.
Simple versions of these clocks were installed in towers throughout Europe but would not always be recognisable as a modern clock. For example the more basic types did not always use dials or hands. Rather they would still use bells to announce canonical hours or intervals between set times of prayer. The more sophisticated astronomical clocks would have had moving dials or hands, and would have shown the time in various time systems, including Italian hours, canonical hours, and time as measured by astronomers at the time.
Remarkably, these 14th century examples possessed the fundamentals which all clocks would have right up to the digital age:
• Power from a falling weight to drive the mechanism, supplemented by a coiled spring. • The repetitive motion that controls the power, and which allows the energy to be released in small bursts, or seconds, rather than all at once. • The interlocking wheels that are connected from the power supply to the indicators. • Such indicators as dials, hands, and bells.
Yet while the clocks of yesteryear may be vastly different from what we're used to today the principles of timekeeping laid down in civilisations dating back to hundreds of years BC are the same principles that govern our time keeping today. So next time you look at your clock, you are actually face to face with technology that is thousands of years old!