John Arnold & Son No. 23 two-day marine chronometer in octagonal mahogany box
Record status
Individual type · partial
Period
circa 1784
This two-day marine chronometer was constructed by John Arnold & Son in London circa 1784. It is housed in an octagonal mahogany box featuring concealed joints and an eight-segment radially jointed lid with a glazed brass bezel.
The white enamel dial is marked with Roman numerals, Arabic five-minute outer markers, and an expansive subsidiary seconds ring, signed 'JOHN ARNOLD / LONDON / No.23'. According to the source, the movement incorporates a full-plate fusee setup with Harrison's maintaining power, an early Arnold spring detent escapement, a blued-steel helical balance spring, and an early Arnold 'Z' balance with bimetallic segments.
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
- Two-day marine chronometer
- Balance
- Early Arnold 'Z' balance
- Box Type
- Octagonal mahogany box
- Escapement
- Early Arnold spring detent escapement
- Dial Signature
- JOHN ARNOLD / LONDON / No.23
- Place recorded
- United Kingdom
- Plate Engraving
- John Arnold & Son / London, No.23 Inv. et Fecit
- Maker / attribution
- John Arnold & Son
Design
- Dial and Hands
- The 106.1 mm diameter white enamel dial is attached to the pillar plate with three pinned feet and signed 'JOHN ARNOLD / LONDON / No.23'. The layout includes Roman hour numerals, Arabic five-minute markers, and a large subsidiary seconds dial. The seconds dial features Arabic ten-second numerals and radial batons. The hands consist of a blued-steel spade and poker set, with a counterpoised seconds hand. The rear of the dial bears a red enamel 'N 23' marking, and there are traces of black paper tape noted on the back.
- Visible features
- • Eight-segment radially jointed mahogany lid surrounding a circular glazed aperture within a brass bezel. • White enamel dial featuring Roman numerals for the hours, outer Arabic numerals at five-minute intervals, and a large subsidiary seconds dial. • Central blued-steel spade hour hand, poker minute hand, and a long counterpoised seconds hand. • Octagonal mahogany case with a small keyhole escutcheon centered on the front facet.
- Case Construction
- The chronometer is housed in an octagonal mahogany box measuring 93mm high, 167mm wide, and 167mm deep. The box is veneered in mahogany over a mahogany carcass with concealed joints and a slightly stepped base. The lid features eight radial segments and an 11cm glazed aperture with a moulded brass bezel; the glass is secured with a plaster fillet. A brass escutcheon is flush-mounted on the front keyhole. The box lid utilizes brass hinges described as later additions, likely from the twentieth century. The base contains a swiveling brass dust shutter for winding, and the exterior sides feature pairs of holes which may indicate the original location of loop handles.
- Movement and Escapement
- The movement is a full-plate fusee type with four tapered cannon-style pillars. The potence plate is engraved 'John Arnold & Son / London, and No.23 Inv. et Fecit.' The mechanism includes Harrison’s maintaining power and an early Arnold spring detent escapement. The assembly features an early 'Z' balance with bimetallic rim segments and a blued-steel helical balance spring. The upper balance pivot includes a rose-cut diamond endstone. While the general finish is described as high, the brass wheel work exhibits some surface blistering, and the gold passing spring is considered a replacement.
Identification
- Reference
- ZAA0012
- Serial number
- 23
- 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: Internal movement features including the fusee, 'Z' balance, and spring detent escapement are cited from the museum documentation and not visible in the closed exterior view.
- Research required: The source notes that the lid's brass hinges are later replacements, likely from the twentieth century.