Instruments · Marine chronometer
Marine chronometer by John Hind
- Maker / attribution
- John Hind (maker)
- Date
- 1793
- Historical period
- Precision & Scientific Horology (1750 – 1850)
- Country of origin
- Unrecorded in source
- Object type
- Marine chronometer
- Materials / technique
- mahogany; brass; steel
- Dimensions
- Overall: 120 x 170 x 157 mm
- Holding institution
- Royal Museums Greenwich
- Accession / object no.
- ZAA0007
- Credit line
- National Maritime Museum, Greenwich, London, Caird Collection
- Catalogue title (original)
- Marine chronometer (English)
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Record summary
Held and catalogued by Royal Museums Greenwich (object number ZAA0007), this is a marine chronometer by John Hind, dated 1793. The Atlas places it in the Precision & Scientific Horology period (1750 – 1850) of its Instruments collection. Materials and techniques recorded by the source: mahogany; brass; steel. Recorded dimensions: Overall: 120 x 170 x 157 mm. The record is illustrated with 2 photographs.
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
Catalogue description — Royal Museums Greenwich
This marine chronometer has a fusee movement with an Arnold-type spring detent escapement. This instrument was almost certainly originally made by John Arnold and would have been mounted in an octagonal mahogany box similar to that of Arnold No. 23 (ZAA0012). It is uncertain when it was fitted into the current box. Thomas Prest, who signed the inside of the fusee, was Arnold’s principal finisher and foreman at the Well Hall manufactory. The chronometer was perhaps a special order from Arnold, for resale by Hind the watch jeweller (or just possibly by John Hinde the instrument maker), and would explain the absence of Arnold’s name on the dial and also on the movement, where it would normally have been engraved. The ‘1793’ on the dial is thus certainly a date. The identities of Watson and Phillips, who probably repaired the movement in 1893, are unknown. Watson may have been William Watson, who is known to have been working in High Holborn in the first part of the twentieth century.
Historical context
Precision & Scientific Horology (1750 – 1850)
Harrison solves longitude; Mudge invents the lever; Breguet's Paris workshop defines the modern watch.
The longitude problem was solved by the marine chronometer and lunar distance methods; dividing engines made precision scales possible, and observatories set time by transit instruments.
Read the period in the timelineMore instruments from this periodEarlier: Early Modern Horology
Atlas type guide
Marine chronometers
A marine chronometer is a precision timekeeper carried at sea to find longitude: the navigator compares local noon, observed with a sextant, with the time at a reference meridian kept by the chronometer. Each hour of difference corresponds to fifteen degrees of longitude. John Harrison proved the method in the 1760s; Pierre Le Roy, Ferdinand Berthoud, John Arnold and Thomas Earnshaw then developed the detent escapement and the compensation balance that made chronometers practical to manufacture.
By the nineteenth century London, Liverpool, Le Locle and Glashütte supplied navies and merchant fleets. A typical box chronometer has a spring-detent escapement, a fusee to equalise mainspring torque, a bimetallic compensation balance with a helical balance spring, and is mounted in gimbals inside a wooden box so that it stays level.
What to look for
- Gimbals and a three-tier wooden box with a glazed inner lid.
- A power-reserve ('up and down') indicator on the dial, usually showing 56 hours on two-day instruments.
- Spring-detent escapement and a cylindrical (helical) balance spring visible through the movement.
- Admiralty or navy marks (broad arrow), and rating certificates from observatories.
- The maker's number on the dial and movement; many makers' registers survive, allowing dating.
Dating clues
- Earnshaw-type spring-detent chronometers became standard after about 1800.
- Auxiliary compensation devices on the balance appear from the mid-nineteenth century.
- Quartz and radio time signals ended routine use of mechanical chronometers in the 1970s and 1980s.
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.
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