The Mists of Time...
Below, Prof. Sky Alton introduces us to an interesting precursor to the pendulum clocks we see today.The Wonders of Water ClocksBy Prof. Sky Alton
Ever heard of a water clock? They’re actually one of the oldest methods for measuring time that we know of.
With a water clock, also known as a clepsydra, time is measured by observing liquid in a container. Either you have a container that’s slowly filling with water or you have one that’s slowly emptying - you can tell how much time has passed by markers on the sides of the container, showing how much water has flowed in or out. Obviously, for the clock to be accurate, the flow of water has to be consistent at all times. Great care has to be taken with the shape of the container and size of the hole the water drips through to get the rate right. Many different civilisations have developed and relied on water clocks throughout history. Egypt, China, India and the territories inhabited by the Ancient Greeks and Romans are just some of the places we have found evidence of them being used. Many of these civilisations added complex components to the clocks to make them more efficient, including reservoirs, waterwheels, floats and automatons (machines designed to automatically do a job without human intervention). Here, rather than observing the water itself, you often watched components that were driven by the water. Some of the most sophisticated and beautiful designs come from Arabic inventor and engineer, Ismail al-Jazari. He strove to create clocks that could be adjusted to account for the different lengths of the days throughout the year. His castle clock, invented in around 1206, was so mind-blowingly complex and adaptable that people regard it as one of the first analogue computers (it was incredibly fancy too - it featured 5 automatons which could play music!). While the water clock fell out of favour when the pendulum clock (the ticking clock we’re familiar with today) was invented in the 17th century, it remains a truly fascinating example of just how ingenious people can be. |