John Arnold & Son Marine Chronometer No. 14/104
Record status
Individual type · partial
Period
1790
This eight-day marine chronometer is catalogued by the British Museum as made in 1790 in London by John Arnold & Son. It is signed on the dial 'John Arnold and Son London, No.
14' and on the back plate 'John Arnold and Son London No 14/104 Invt et Fect.' The source notes that chronometer No. 14 was later improved and re-numbered 104. The movement incorporates a spring-detent escapement, a free-sprung gold helical balance spring, and Arnold's 'YZ' bimetallic temperature-compensation balance. Housed in an octagonal mahogany box, the instrument accompanied Captain George Vancouver between 1791 and 1795 on voyages surveying the Pacific coastline of North America.
Evidence at a glance
- Linked sources
- 1
- Photograph views
- 1
- Catalogue references
- 0
Counts describe this entry’s documentation, not authenticity, rarity or completeness. Photographs may show one specimen; check each caption and licence.
Technical characteristics
- Type
- Eight-day marine chronometer
- Makers
- John Arnold & Son
- Balance
- John Arnold 'YZ' balance
- Escapement
- Spring detent
- Museum number
- 1958,1006.2069
- Place recorded
- United Kingdom
- Dial inscription
- John Arnold and Son London, No. 14
- Maker / attribution
- John Arnold & Son
- Historical expedition
- Captain George Vancouver voyage (1791–1795)
- Back plate inscription
- John Arnold and Son London No 14/104 Invt et Fect.
Design
- Visible features
- • Octagonal mahogany casing with brass side pivots and keyhole on the front. • Glazed circular brass bezel enclosing a silvered dial. • Engraved Roman numerals for the hours with Arabic five-minute markings. • Large subsidiary seconds dial positioned at the lower half of the dial. • Blued steel hour, minute, and counterpoised seconds hands.
- Identity and Provenance
- The instrument is signed on the back plate as 'John Arnold and Son London No 14/104 Invt et Fect.' and on the dial as 'John Arnold and Son London, No. 14'. Documentation suggests the dual numbering indicates the chronometer was later improved and re-numbered 104. The chronometer is documented as having accompanied Captain George Vancouver on his expedition to the Pacific coastline of North America between 1791 and 1795. It was part of the Ilbert collection, donated to the British Museum in 1958 by Gilbert Edgar after being purchased by Courtenay Adrian Ilbert in 1932.
- Construction and Housing
- The movement is housed in an octagonal mahogany box with a hinged glazed lid and a lock. The box contains brass pivots on the exterior, indicating it was at some time suspended in gimbals. The winding hole in the bottom is brass-lined with a rotatable escutcheon plate. The movement features full-plate construction with a massive front plate, double-recessed under the dial. The brass components are decorated with hand-applied spotting.
- Mechanism and Components
- The chronometer utilizes a fusee with Harrison's maintaining power and an Arnold spring-detent escapement. The 'YZ' type balance comprises three bimetallic segments screwed to radiating brass arms, with the segments consisting of an inner rim of platinum and an outer rim of a silver, copper, and zinc alloy. A free-sprung gold helical balance spring of 7½ turns is fitted undersprung between the balance and the back plate. The going train pivots run in pierced jewels, with endstones on all back plate settings, including a diamond for the balance staff.
Identification
- Serial number
- 14/104
- Source note
- Facts transcribed from the linked source listing or collection record. Attribution and specifications are source-reported and have not been independently authenticated.
Catalogue references
No catalogue numbers recorded. Numbers are only published once transcribed from a verified edition of a standard catalogue — they are never inferred.
Research required
- Research required: Source notes conflicting dates in commentary headings (c.1778 versus 1790), though the catalogued production date is 1790 and the great wheel bears a 1790 inscription.
- Research required: Internal movement details, escapement, and balance assembly are concealed within the closed casing in the displayed photograph.