History Of Time

Students frequently write or email for information. Some get a long detailed reply, some a short reply and some no reply at all. Your reply depends on how you phrased the question, how much time I have when I read it and whether I think this is a genuine enquiry or just a joke. Asking what are clocks made of begs more questions than answers. Asking 'What is Time' is a FAQ and probably should have been addressed to Steven Hawking.

Time in my experience as a Time Lord is what stops everything happening at once. We never have enough time so use it wisely. Sitting on a beach in the sun is not wasting time, trawling the net might be.  At the risk of wasting time there follows some notes about time and time measurement that might be of interest to students and others. Try not to cut and past into your essay, I don’t want my work marked to closely. If these notes are of any use or interest a short thank you email will be very welcome.

Dividing the day into twenty-four hours of equal length with subdivisions of sixty minutes that are divided into sixty seconds is a comparatively new concept. With the sun rising in the east and setting in the west on a regular basis the concept of a day was not too difficult. This day divided into two periods, one dark and one light. A dark period for sleep or clubbing and a light period for work or sleep depending on your age. Light and dark periods vary in length with the seasons and are known as a natural day. While observing the natural day it was also noted that the moon would change regularly. Twelve moons between similar seasons gave rise to the year and a natural division into twelve moons or months. It is these divisions that may have given rise to the duodecimal counting system whereas the decimal system is based on ten fingers and used by people without a calculator.

The first clock was probably just the moving shadow of a tree. Later a sundial produced the shadow. Using a sundial in the dark period is hopeless and it won’t work on cloudy days. In some areas in the Middle Ages smog created by the coal burning industries obscured the sun.  A sand-glass was of some help in the dark period but only ran for a short period. OK for timing an egg but not much use for timing the start of a church service.

With advances in medieval glass blowing, sand-glasses started to be used by the clergy to time the length of services and to time their sermons to just an hour. Sand glasses started to get quite complex with some having four glasses timing different periods. Oil clocks, originating in Islam, became popular in the early middle ages. Useful in the dark period because they gave light as well as a measurement of the passing of time. Candle clocks appeared at this time too, marking down the candle showed the passing of time. These time measuring devices were only able to measure a period of time but could not tell what time of day it was.

Water clocks or ‘Clepsydra’ could measure time over a longer period and when the water wheel was invented they became much improved. The early Clepsydra or water clock from Islam and China was little more than a bucket with a hole in it. In the Middle Ages water clocks used rising or falling floats to operate a rack and pinion to move a pointer. Water clocks became very elaborate with complications that were often a source of fascination and amusement. There are records of an early medieval water clock where figures of angels would appear every hour, bells would ring, horsemen appeared and a little man, known as a jack, would strike the hour bell with a hammer. There is even a report of a water type clock run on milk, but not why. The court of Alfonso X in Castile was supposed to have a water type clock run on mercury in 1277 and is a very good example of French one upmanship. Water clocks are important because they tested mechanical components that later gave rise to the mechanical clock in the middle ages. Gimpel wrote, “there was no limit to the ambition and imagination of the medieval engineers and technicians, yet of all their inventions, the mechanical clock is perhaps the one that symbolises their ultimate achievement”.

Lewis Mumford, also writing about the importance of the clock as a symbol of the technological advanced of the age wrote, “The clock, not the steam engine, is the key machine of the modern industrial age. At the very beginning of modern technics appeared prophetically the accurate automatic machine. In its relationship to determinable qualities of energy, to standardisation, to automatic action and finally to its own special product, accurate timing the clock has been the foremost machine in modern technics and at each period has remained in the lead. It marks a perfection to which other machines aspire”. A big breakthrough permitting mechanical time keeping was the invention of the escapement in the 13th century. This escapement consisted of a wheel that turned with the pull of a weight. An escapement is a way of stopping and starting a wheel to slow down its motion. Ticking is the sound of a wheel being stopped and released one tooth at a time. A tooth is allowed to escape before being caught again, giving rise to the name escapement. The invention of this simple, ingenious, device marked the invention of the mechanical clock.

The word clock comes from the Latin cloca but in the monasteries all types of timekeepers were known as Horologium. Monasteries may have been the first places where clocks came into regular use. Monasteries scattered across Europe at this time were complete communities or villages. Mills, granaries, potteries and workshops were gathered around a central church. Strictly ordered routines with seven daily and once nightly services and prayers were adhered to. Punctuality was important because it was believed that praying simultaneously enhanced the potency of prayer, hence the need for a clock. Clocks became quite common in European churches with the exception of the Greek Orthodox Church where clocks were believed to interfere with eternity and therefore banned. One of the oldest surviving church turret clocks is in Wells cathedral and dates from 1386. The growth of urban centres in the eleventh century led to a busy town like that was ordered very differently to the natural day of the peasant. People needed to arrive at work at a specific time. Shipping relied on high tides to dock and merchants needed to predict those tides for loading and unloading ships. Towns and villages competed with one another to own the best clock.  Clockmakers skills attracted the attention of the rich and royal who as patrons of the clockmakers encouraged the development over the next four hundred years of clocks that became precise, portable and so accurate that on board ship could determine longitude and allow exploration and exploitation of the world. So now you know whom to blame.