This eight-day marine chronometer has an Earnshaw-type spring detent escapement and an over-sprung balance of ordinary bimetallic construction. It is probably Hatton’s but fitted with later cylindrical brass compensation weights clamped to the rims, as well as a pair of brass screws planted 90° from the arms. The short rims, by the end of the each arm, have a brass mean-time screw fitted.

The early history of the chronometer remains unknown, but the Admiralty records show that it was purchased for Royal Navy use “before 1821” and served much of its life on the waters around Africa. In 1821 it was issued to Captain Culfield of the survey ship Barracouta, who was ordered to join HMS Leven (Capt. William Fitzwilliam Owen) at the Cape of Good Hope to survey and chart the east coast of Africa. The ships also completed a survey of Madagascar, charted all six islands of the Îsles de Los, and surveyed at the foot of Mount Cameroon. In 1862 the chronometer was on HMS Investigator – a wooden paddle vessel surveying rivers in West Africa, including the expedition up the River Niger. The instrument returned to Greenwich from Ascension Island, on 28 May 1866. In 1873 it was on survey duty on HMS Nassau on the East Coast of Africa and took part in the bombardment and destruction of Mombasa Fort, in 1875. In1908, it was exhibited as part of the 1908 Franco-British Exhibition, and as part of the Japan-British Exhibition of 1910. The chronometer thus served for well over a century. Between 1842 and 1911, the period during which repair records were kept, it was repaired and up-dated eighteen times. At an unknown date, ownership transferred to the Royal Greenwich Observatory. Upon the RGO’s closure in 1998, the chronometer became the property of the NMM.