Original year-going movement by Thomas Tompion, 1676 & Three Tompion Clocks -- Flamsteed House, Royal Observatory, Greenwich, UK - UK Historical Markers on Waymarking.com

An odd-looking clock encased in glass in the Octogon Room at Flamsteed house conceals a very simple (yet revolutionary) movement that made highly accurate clocks possible. Accurate timekeeping was incredibly important on the high seas, where knowing the correct time helped immensely with navigation.

Tompion's 1676 clock, originally obscured behind panelling, is today removed from its hiding place and, although modified somewhat, has been put on display behind plexiglass for all to see and appreciate.

The interpretive sign at the base of the pendulum reads as follows:

"ORIGINAL YEAR-GOING MOVEMENT BY THOMAS TOMPION, 1676

This is one of the two clock movements originally housed behind the walnut grained paneling. When it was removed from the setting, the movement was adapted for domestic use. This meant replacing the escapement and the long pendulum. The clock now beats every second, rather than every 2 seconds, and has a 39 inch (1m) long pendulum.

Did you know?

Flamsteed and Tompion agreed on the use of a new type of mechanism in these clocks- the “dead beat” escapement, which became the standard for precision pendulum clocks

[drawing]
Reconstruction of Tampion’s “dead-beat” escapement
by David Penny
London, 1994

Nearby, a second historic marker discusses three other Tompion Clocks as follows:

"THREE TOMPION CLOCKS

The original mechanisms and dials up to clocks on the left of the door were made in 1676 by Thomas Tompion. They were later sold by John Flamsteed’s widow and converted into long case clocks. One is now in the British Museum and the other is on display elsewhere in this room. These replica clocks demonstrate to second swing and the unusual front to back motion of the original 13 foot pendulums, suspended over the movements.

Very little is known about the clock on the far right, which was also removed from the observatory by John Flamsteed’s widow in 1719. It probably indicated sidereal time (star time). This is measured by the rotation of the earth in relation to the stars (rather than relative to the sun).

Did you know?
With comprehensive original “dead-beat” escapement, the pendulum swung fore and aft, not side to side, making bay windows in the paneling necessary."

Type of Historic Marker: Interpretive sign Historical Marker Issuing Authority: Royal Museums Greenwich Age/Event Date: 01/01/1676 Related Website: [Web Link] Give your Rating:

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