Ferdinand Berthoud La Montre à Longitude Verticale No. 46
Record status
Individual type · partial
Period
1790
Maker / issuer
Ferdinand BerthoudCompleted in 1790, La Montre à Longitude Verticale No. 46 is a brass vertical marine chronometer designed by Ferdinand Berthoud and constructed by Vincent Martin.
Source notes describe the instrument as a versatile precision timekeeper conceived to serve at sea, as a deck or pocket watch, and as a desk timepiece via its detachable gimballed suspension. The movement features a manual fusée and chain, maintaining power, a detached pivoted detent escapement, and temperature compensation combining steel and copper. The front dial plate integrates three enamel subsidiary dials for time indications, exposed clickwork, and engraved signatures.
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
- Vertical marine chronometer
- Year
- 1790
- Material
- Brass
- Dimensions
- 72mm diameter
- Escapement
- Detached pivoted detent escapement
- Case Number
- 46
- Constructor
- Vincent Martin
- Place recorded
- France
- Maker / attribution
- Ferdinand Berthoud
Design
- Visible features
- • Three white enamel subsidiary dials display hours, minutes, and seconds under a glazed front. • Gilded dial plate engraved 'No. 46 / M.e à Longit.de' and 'Inve. par / Ferdinand Berthoud / 1790'. • Exposed clickwork ratchet and blued steel click visible on the dial plate. • Cylindrical brass drum case suspended by a gimbal pivot arm on an arched brass stand resting on a circular base with feet.
- Technical Specifications
- The movement incorporates a manual fusée and chain with maintaining power. It utilizes a detached pivoted detent escapement and a balance beating at a frequency of 2 Hz (14,400 vph). For temperature compensation, Berthoud used a system employing steel and copper, noting this as a departure from traditional grid-iron designs.
- Object Identity and Documentation
- Completed in 1790, this vertical marine chronometer, designated No. 46, was constructed by Vincent Martin, described as Berthoud’s foremost pupil and 'horloger de la Marine' in Brest, working to Berthoud's specifications. The instrument is documented in Ferdinand Berthoud’s contemporary technical literature; specifically, the opening 22 pages of his 1792 publication, 'Traité des Montres à Longitudes', are devoted to this chronometer. It is also featured on the frontispiece of his 1802 work, 'Histoire de la Mesure du Temps'.
- Construction and Dial Configuration
- The timepiece is housed in a 72mm cylindrical brass drum case. It features a detachable gimballed mounting for marine use or table-top display, though the associated brass stand is catalogued as a modern recreation. The gilded dial plate is engraved 'No. 46 / M.e à Longit.de' and 'Inve. par / Ferdinand Berthoud / 1790'. Three white enamel subsidiary dials display hours, minutes, and seconds, while the dial plate also features an exposed clickwork ratchet and blued steel click.
Identification
- Serial number
- 46
- 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: The brass stand is catalogued by the source as a modern recreation rather than an original 18th-century component.
- Research required: Internal escapement and gear train are not visible in the photograph.