An eight-day astronomical regulator by Dent, London, number 2012, circa 1874

The movement has angled shoulders to the curled and lacquered plates, which are united by four cylindrical screwed pillars. The four-wheel movement has Harrison’s maintaining power and dead-beat escapement. The painted cylindrical driving weight is suspended via a solid brass pulley on a double line to the barrel, which is cut with 13 turns. The movement is fixed to a cast iron bracket with integral A-framed support from which the zinc and steel temperature compensated pendulum is suspended. The painted dial is laid out in traditional regulator fashion and has three circular apertures through which electrical contacts could be observed. These contacts have since been removed.

One of 12 regulators commissioned from Dents for the 1874 Transit of Venus expeditions, it was used for the Honolulu observations. A decade later it was installed as the reserve mean solar standard alongside the Shepherd motor clock, which it superseded in 1893. In 1925, under direction of the Astronomer Royal, Sir Frank Dyson (1868-1939), this clock and Dent 2016 were converted to transmit time signals, via telephone, to the BBC for the transmission of the six pips. Both clocks were magnetically corrected by the Shortt free-pendulum clock system.

Object Details

ID: ZBA1292
Collection: Timekeeping
Type: Clock serial number 2012
Display location: Not on display
Creator: Edward John Dent & Co.
Date made: 1874
Credit: National Maritime Museum, Greenwich, London
Measurements: Overall: 1445 x 445 x 220 mm
Parts: An eight-day astronomical regulator by Dent, London, number 2012, circa 1874