Kew Observatory

A small house in a London park, built for George III to watch the 1769 transit of Venus, became for a century and a half the place where Britain tested instruments, recorded the weather and the magnetic field and trained observers.

A royal observatory

The King's Observatory in the Old Deer Park at Richmond was built in 1769 for George III, in time for the transit of Venus that year. After the king's death, it fell into disuse until 1842, when the British Association for the Advancement of Science took over the building, with Francis Ronalds as honorary director. Ronalds installed instruments that recorded weather and magnetism photographically on moving paper, among the first self-recording meteorological instruments.

Responsibility passed to the Royal Society in 1871 and the observatory was then run by a committee, with superintendents such as John Welsh and Balfour Stewart.

An instrument-testing house

Kew became the national standard for testing instruments. It verified thermometers, barometers and other meteorological instruments and issued certificates, and the Kew-pattern barometer became a standard. Kew's yearbooks record the daily readings of magnetism, temperature and pressure, and give details of the instruments, a rare example of full metadata in the nineteenth century.

Its staff and visitors included Francis Galton, who worked at Kew in the 1850s on meteorological instruments. Edward Sabine's magnetic survey of the globe made Kew one of the nodes of the international magnetic network.

Moving away from the trams

Electric traction on London's tram and underground lines disturbed the magnetic measurements. In 1908 the geomagnetic instruments moved to Eskdalemuir in the Scottish borders, a quiet site. The National Physical Laboratory was set up at Kew in 1900 and later moved to Teddington; the Meteorological Office took over the observatory in 1910 and closed it in 1980. The building survives and is now used as offices.

A bridge between science and trade

Kew served makers and users of instruments as much as scientists. By certifying thermometers and barometers, it created a market for reliable instruments and let ships' captains, observers and clinicians trust a reading. The Kew certificate was an early form of traceability: an instrument is compared with a standard, and the comparison is written down. In 1900 the National Physical Laboratory was set up at Kew, and later took over the role of national standards. Kew's history shows how a scientific institution can be the origin of a standards body, and how a site can serve a quality system for a century.

Instruments and technologies

  • Photographic self-recording instruments A beam of light reflected from a magnet or from a barometer's mercury fell on photographic paper wrapped round a clock-driven drum, making a continuous trace.
  • Kew-pattern barometer A standard mercury barometer with a fixed cistern, verified against the Observatory's standard.
  • Verification service Instruments sent from makers and from the Navy were compared with the standards and given a certificate of corrections.

The people

  • Francis Ronalds First honorary director; built early self-recording instruments.
  • Edward Sabine Organiser of the global magnetic survey, closely tied to Kew.
  • John Welsh Superintendent who developed the observatory's balloon and meteorological work.

Timeline

  • 1769 Built for King George III, in time for the transit of Venus.
  • 1842 The British Association takes over the building, with Francis Ronalds as honorary director.
  • 1871 Responsibility passes to the Royal Society.
  • 1900 The National Physical Laboratory is established at Kew.
  • 1908 Geomagnetic instruments move to Eskdalemuir because of electrical interference.
  • 1910 The Meteorological Office takes over the observatory.
  • 1980 The Met Office closes the observatory.

Key lessons for observation today

  • A calibration service is a network function Kew's certificates made thermometers from different makers comparable. Qualification of instruments is part of network design.
  • Move when the environment changes The magnetic instruments had to leave when trams were electrified. Radio, power and urban noise shape where an instrument can work.
  • Publish the metadata with the readings Kew's yearbooks list instruments, corrections and methods. Metadata published with the data is what makes it reusable.

Sources

  • Wikipedia, King's Observatory (secondary)
  • Francis Galton, Memories of My Life, chapter XVI
  • British Geological Survey, Kew Observatory yearbook 1882–1883