Overview of the History of Time Clocks
Posted on 24th July 2019 at 16:02
The pre-occupation of people with "Time" can be traced back over 4000 years. This article is a small overview of the history and the evolution of clocks and watches over the ages.
In todays world we are all familiar with time being measured in terms of 60 seconds and 60 minutes. Historians have traced this system back to 2000BC where the Sumarians (First civilisation known in Mesopotamia <southern Iraq>.
The Egyptians pioneered the use of Obelisques to track the movement of the sun to measure time. They were the first people to divide the day into to 12-hour periods. The oldest Sundial can be traced back to 1500BC. Sundials were fine during daylight hours but of no use during the night or on dull days. The Egyptians therefore pioneered a system of using the stars and invented a water clock, the earliest of which can be traced back to a tomb inscription of the 16th Century BC. The use of water clocks continued throughout the centuries being refined to give more accuracy, the initial problems being that the pressure of water from the header tank would be greater when the tank was full and lessen as the tank emptied.
In 520AD the first Candle clock was mentioned originating from the Far East and this found favour across the Northern Hemisphere (China, Japan, Middle East, India and Europe). Around the 6th Century AD the incense clocks started to appear thought to have been of Buddhist origin. As they burned evenly and without a flame, they were much safer to use indoors. They came in different forms having weights which lowered to show the time as the incense burned down, one even had different smells changing as the hour changed.
By the 11th century water clocks had become very accurate and by means of weights, pullies and cogwheels could now turn an hour hand rotating round a dial.
Time keeping aboard ship wasn’t so easy and it is believed that from the 11th century the hourglass was used in conjunction the magnetic compass. When the Globe was circumnavigated in 1522 by Ferdanand Magellan it is said that he used 18 hourglasses during the journey.
The first mechanical clocks emerged in the 14th Century with the invention of the Verge and Foliot clock a rotating wheel driven by weights that engaged with a balance wheel. By a clever mechanism a rod connected to the Foliot would move from side to side and when it reached the end of its movement would reverse the direction of the Folliott giving an oscillatory movement. Although records exist of earlier clock towers using this method the oldest surviving one is in Salisbury Cathedral dating from around 1386 and has some of its original parts. The Verge and Foliot were lost when the clock was converted to a pendulum clock, however replicas were built and installed in 1956 when it was restored to its original state. By 1475 the first clock face that displayed both hours and minutes are mentioned in manuscripts and became popular in 15th century Germany.Click on this text to edit it.
In 1656 the Pendulum clock came into being. The pendulum has a harmonic oscillation that swings backward and forward in a precise time depending on its weight and length. It therefore became the most accurate form of keeping time until around the 1930’s. It effectively removed the need for the Verge and Folliatt mechanism to produce the oscillatory movement to drive the gearing to either strike a bell or move hands around a clock face.
The invention of the Hairspring that could provide the important oscillatory motion came into being in the early 15th century allowing more portable clocks to be made. However, these weren’t very reliable. But it wasn’t until 1675 when the balance spring came into being which could more tightly control the oscillatory movement. With this invention the pocket watch was a reality and in time the wristwatch came into being using the same principle.
The first electronic clock appeared during the 19th century where an electromagnetic pendulum provided the oscillatory movements required. Towards the end of the century the piezoelectric properties of Crystalline quartz were recognised, and this resulted in the first quartz clock being produced in 1927.
The most accurate clocks today are the atomic standards. First worked on in the USA in 1949 showed promise but was not accurate compared with Quartz clocks. Further development in England by the National Bureau of Standards the first caesium standard became a reality and was adopted in 1967. Its accuracy is 30 billionths of a second per year.
For a more detailed insight into Mechanical through to Electronic Timepieces there is a fascinating museum "The Museum of TimeKeeping" at Upton Hall near Newark on Trent.
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