Nocturnal with horizontal dial and moondial
Record status
Individual type · partial
Period
1588
This 52 mm diameter gilt brass nocturnal, dated 1588 and of French origin, serves as a multifunctional scientific instrument. It combines a nocturnal, a horizontal dial, and a moondial with lunar time conversion capability.
The obverse features a horizontal dial with a folding gnomon calculated for a latitude of approximately 49 degrees, accompanied by a moondial volvelle and a lunar age scale. The compass, integrated into the handle, displays cardinal directions with a 10-degree east deviation. The reverse functions as a nocturnal, containing zodiacal scales, a Julian calendar, and a central rotating volvelle with a 24-hour scale and a 'LIGNE DE FOY' index.
The instrument retains its original wooden storage case with red lining. It is currently held in the British Museum collection.
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
- Date
- 1588
- Type
- French nocturnal
- Origin
- French
- Material
- Gilt brass
- Dimensions
- 52 mm diameter
- Place recorded
- France
- Compass Deviation
- 10 degrees east
Design
- Visible features
- • Folding gnomon for horizontal sundial • Compass integrated into the handle • Ligne de foy index on the nocturnal side • Wooden case with red lining
- Documentation and Provenance
- The instrument is part of the collection at the British Museum, where it was registered under the number MLA 1891,8-3.1 following its purchase in 1891. The instrument is stored in a dedicated wooden case with interior red lining. The nocturnal is catalogued in F. A. B. Ward's 1981 publication, 'A Catalogue of European Scientific Instruments in the Department of Medieval and Later Antiquities of the British Museum', appearing as entry number 209.
- Front Dial and Moondial Features
- The obverse of the circular brass plate is configured as a horizontal dial, featuring a folding gnomon calibrated for a latitude of approximately 49 degrees. An hour scale numbered IV to XII to VIII occupies the outer edge, with half-hours marked by small dots. Internal to this is a lunar age scale numbered 1 to 29. A volvelle is located within the centre, serving as a moondial for converting lunar time to solar time. This mechanism includes a circular aperture for indicating moon phases and an index that correlates with the moon's age scale. The date '1588' is engraved on the rim near the lunar scale. A compass is attached to the instrument's handle, featuring cardinal points marked by initial letters of Latin names. The compass demonstrates a 10-degree east deviation.
- Nocturnal and Calendar Functions
- The reverse of the plate functions as a nocturnal. It incorporates several concentric scales: the outermost displays zodiacal signs with 30-degree divisions, shaded for clarity. A Julian calendar scale follows, featuring abbreviated Latin month names, though the source notes a discrepancy in the division intervals used for this scale. At the centre lies a rotating volvelle marked with a twice-12-hour scale, arranged anticlockwise. Small teeth on this disc indicate full hours. An index arm, labeled 'LIGNE DE FOY', rotates over the central dial, allowing the user to align the instrument with the time of year using the two indices at 12 o'clock.
Identification
- Inventory Number
- MLA 1891,8-3.1
- 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 Julian calendar scale appears confused with the zodiacal scale division
- Research required: The exact maker remains unattributed