Yesterday my knowledge of clocks was greatly extended.
I visited
Upton Hall with members of the U3A Science and Technology group.
For the benefit of readers too lazy to click on the link, Upton Hall is the headquarters of the British Horological Institute. The Institute provides correspondence courses in clock and watch making, conducts examinations and awards qualifications. It has a large collection of clocks, dating from the sixteenth century to the present day. Almost all have been acquired as gifts.
We were conducted round the collection by Viscount Middleton, who is the curator, and of course himself a horologist.
The tour far exceeded one's normal expectations of a guided tour; it amounted to an erudite, entertaining and highly informative seminar on the history and technology of clock making and time keeping.
We began by contemplating a reconstruction of a medieval clock. That was designed to divide both day and night into twelve hours each, so that for most of the year it had to run at different speeds during the day and night. It therefore had an adjustable governor, which would normally have been altered at dawn and again at dusk so that the speed of the clock would vary according to the hours of daylight and dark..
We moved on to a master clock with built in electrical generator to provide the electrical pulses that controlled the slave clocks. Power was provided by a two hundredweight weight that had to be wound up daily.
Another remarkable exhibit was Britain's first speaking clock, incorporating an early example of an optical reader.
There was also a clock that indicated the state of the tide. Another clock had a special lock to prevent the servants getting inside the case to put it back when they were behind with their work.
Not all clocks have twelve hours on the dial; there was one with only four hours, so the hour hand made six circuits every day (there was no minute hand), and one depended on background knowledge to decide which of the six possible times applied.
A separate display of watches and small clocks included the alarm watch Captain Scott used to wake him up every two hours so he could take exercise to avoid frostbite, and there were several clocks in which all the parts were made of wood.
We concluded by examining a clock specially constructed to commemorate the 150th Anniversary on the BHI. It had a glass case through which one could see what was going on inside and was unusual in having three pendula, intended to compensate for the effects of movement.
Having spent a fascinating two hours looking at the collection, we adjourned to the Southall Minster Refectory (as they call their tea room) for tea.
Upton, by the way, is a village in Nottinghamshire, on the road from Southwell to Newark.