This mercury barometer and thermometer has a brass case, painted black, to protect the glass tube containing mercury. There is a silvered scale with a vernier for accurate reading. It is mounted on gimbals so that it remains level when in use. It is a Meteorological Office standard barometer, developed around 1855 by the Kew Committee of the British Association for the Advancement of Science, which met a Kew Observatory. It became known as the Kew Pattern barometer. The makers of this example, Negretti & Zambra, were among the best known London manufacturers of meteorological instruments in the late 19th century and early 20th centuries.

Farmers, sailors and fishermen had used barometers throughout the 18th and early 19th centuries to predict changes in the weather, but in 1854 the Meteorological Department of the Board of Trade (later the Meteorological Office) was established with the aim of gathering data from as many locations as possible to be able to predict weather patterns. In order to gather reliable data from a range of different sources, Admiral Robert Fitzroy (1805–65), the first head of the department, oversaw the design and manufacture of a series of standardized barometers. The Meteorological Office standard barometer, or Kew standard barometer, was developed for use on merchant ships.