Quartz clock equipment, mounted on 6'6" standard rack, R.3191, with box of accessories and spare frequency divider unit

Record summary

Held and catalogued by Science Museum Group, London (object number 1947-310), this is a quartz clocks; quartz clock equipment; frequency divider units by General Post Office Research Station, Dollis Hill, made in London, England, Dollis Hill, Dollis Hill; London; England, dated 1942. The Atlas places it in the Golden Age of Mechanical Watchmaking period (1900 – 1945) of its Clocks collection. Recorded dimensions: overall: 650 mm x 470 mm x 170 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

Quartz, atomic and electronic time standards

In 1927 Warren Marrison and J. W. Horton at Bell Telephone Laboratories built the first quartz clock, which used the piezoelectric vibration of a quartz crystal as its oscillator. Quartz clocks replaced pendulum regulators in observatories in the 1930s and 1940s and revealed irregularities in the Earth's rotation. In 1955 Louis Essen and Jack Parry at the National Physical Laboratory in Britain operated the first practical caesium atomic clock; in 1967 the SI second was redefined in terms of the caesium-133 transition.

Atomic and quartz standards are distributed by radio time signals, telephone 'speaking clocks', and today by satellite navigation and network time protocols. Objects in this group — oscillators, frequency dividers, receivers, master clocks — document the transition from mechanical to electronic timekeeping.

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.

Read next:The Quartz Revolution era