Electric wall impulse clock by Synchronome Co Ltd

Record summary

Held and catalogued by Royal Museums Greenwich (object number ZBA4533), this is an electric wall impulse clock by Synchronome Co Ltd, made in England, dated c. 1920. The Atlas places it in the Golden Age of Mechanical Watchmaking period (1900 – 1945) of its Clocks collection. Materials and techniques recorded by the source: wood; brass; steel; copper wire; painted surfaces. Recorded dimensions: Diameter: 304 mm;Overall: 51 mm. The record is illustrated with 1 photograph.

Assembled from the source record's structured fields. Dates and attributions are given as the source states them; where a field is missing the Atlas leaves it blank rather than estimating.

Catalogue description

Atlas type guide

Electric and synchronous clocks

Alexander Bain patented the electric clock in 1841, and through the later nineteenth century electricity was used both to drive pendulums and to distribute time. Master clocks sent impulses every half-minute or minute to subsidiary ('slave') dials across factories, schools, railway stations and post offices; Matthäus Hipp's toggle (1842) kept pendulums swinging with minimal interference. William Hamilton Shortt's free-pendulum clock (1921), with a slave pendulum doing the mechanical work, became the most accurate mechanical clock ever made in series.

In the 1920s and 1930s synchronous motor clocks, which count the alternating-current cycles of the mains supply (50 or 60 Hz), arrived in homes; Telechron in the United States and Smiths 'Sectric' and Ferranti in Britain made them in great numbers. Battery clocks such as the Bulle, Eureka and ATO used electromagnetic impulsing of balances or pendulums.

General guidance written by the Atlas editors about this kind of object. It is not a statement about this particular piece; for that, rely on the source record above and on physical examination.