George James Stebbing (1803—1860) travelled around the world with Charles Darwin on board HMS Beagle and helped him with measuring temperature on at least one occasion. However, Stebbing barely registers in Darwin’s correspondence. The only mention omits even his name, when Darwin told Alexander von Humboldt, in a letter of 1 November 1839, that he had been assisted in measuring the coldness of the sea around the Galapagos Islands by a ‘very careful person’. This person, he explained, had been ‘employed by Capt. FitzRoy (at his own expence) to take charge of the chronometers.’ During the voyage, Stebbing worked mainly with Robert FitzRoy and the assistant surveyor John Lort Stokes.
Listed as ‘Instrument Maker’ on the Beagle’s roster, Stebbing had a very specific and important role. The purpose of the voyage, alongside the hydrographic survey of South America, was to carry twenty-two chronometers that would be used to establish the longitude of various places to produce a connected chain of meridian distances around the world. It was for this reason that the Beagle circumnavigated the globe. The point of these timekeepers was to allow sailors to determine where they were. Degrees of longitude were established by the difference between Greenwich Meantime (the time at which the chronometers were set) and the local time (calculated from the position of the sun) of wherever the ship was. Each hour’s difference was the equivalent of 1/24th of a complete rotation of the earth, that is, 15 degrees.
FitzRoy had taken responsibility for fitting out the Beagle with the most sophisticated scientific instruments available, and six of the chronometers were his personal property. Darwin was impressed. ‘No vessel ever left England with such a set of Chronometers … all very good ones’, he told John Stevens Henslow. While Stokes and FitzRoy were responsible for supervising the readings, it was Stebbing who had to maintain these instruments in good working order. The chronometers, which he wound daily, were delicate and had to kept as stable as possible in often rough seas. Stebbing also had responsibility for the sextants, thermometers, and barometers on board, and for measuring terrestrial magnetism using a magnetometer. At the end of the voyage, the sum of all the parts of the global chain of meridian distances measured using the Beagle’s chronometers, exceeded 24 hours by only 33 seconds. Although FitzRoy thought the discrepancy larger than could be accounted for, he nonetheless considered that Stebbing ‘contributed largely to whatever was obtained by the Beagle’s voyage’ (Narrative 2: Appendix, p. 327).
It is unclear what Stebbing did immediately after the return of the Beagle in 1836, but in 1841 he set up a business as a manufacturer of optical and mathematical instruments in Portsmouth in direct competition with his father, the scientific instrument maker George Stebbing (1774—1847). By 1843, he was established enough in the town to be proposed as Master of a new Freemasons Lodge. By 1858, however, his business had declined and he, once again, became involved in another of FitzRoy’s projects. When FitzRoy was appointed to establish and run the Meteorological Department of the Board of Trade in 1854, one of his first tasks was to supply instruments to ships and coastal stations for recording weather phenomena. FitzRoy increasingly felt the need for a technical assistant, and in 1858 he employed Stebbing to check and deliver barometers.Stebbing continued to work for the Meteorological Department until his sudden death from apoplexy in 1860.
References
[FitzRoy, Robert] 1839. Narrative of the surveying voyages of His Majesty's Ships Adventure and Beagle between the years 1826 and 1836, describing their examination of the southern shores of South America, and the Beagle's circumnavigation of the globe. Appendix to Volume II. London: Henry Colburn.
Holland, Julian. 2013. 'George James Stebbing: Captain FitzRoy's
Instrument Maker', Bulletin of the Scientific Instrument Society 116: 22–9 and 117: 29–40.
‘The Portsmouth Lodge 487’, http://www.hantsandiowprovincialhistory.co.uk (accessed 11 December 2020).
