Ivory Equinoctial Dial
Record status
Individual type · partial
Period
Late 16th century ?
This unsigned ivory equinoctial dial is attributed to late 16th-century France. Constructed from a single leaf measuring 53 x 73 x 6 mm, the instrument integrates multiple timekeeping functions.
The obverse face features an horary quadrant with a limb graduated in degrees, a scale for zodiacal signs, and common hour lines numbered from 5 to 12 to 7. The apex contains the Hebrew tetragram for 'God', and the lower section bears the inscription 'Pour la Latitude de Paris 49'. The reverse contains a Regiomontanus-type dial featuring zodiacal symbols, a scale of latitudes, and hours numbered from 1 to 12. The rims feature a shadow scale with varying numerical divisions.
The instrument includes two terminal scrolls at the top, pierced to function as sights, though one is damaged. The original arm for the plumb bob is currently missing from the device.
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
- French equinoctial dial
- Origin
- French
- Dimensions
- 53 x 73 x 6 mm
- Provenance
- Purchased in 1895
- Place recorded
- France
- Inscribed Latitude
- Paris, 49 degrees
Design
- Visible features
- • The dial is constructed from ivory. • One of the terminal scroll sights is broken. • The plumb bob arm is absent. • The device includes a Hebrew inscription in the apex of the horary quadrant.
- Construction and Design
- The dial is formed from a single piece of ivory, measuring 53 mm in width, 73 mm in height, and 6 mm in thickness. The device features two terminal scrolls at the top edge, which are pierced to serve as sights; the source notes that one of these components is broken. The overall architecture is designed as a multi-functional timekeeper, incorporating both a Regiomontanus-type dial and an horary quadrant. The instrument incorporates a shadow scale distributed across three of its rims, marked with specific subdivisions and numbers. The primary face displays an horary quadrant with a scale of degrees and zodiacal signs, while the reverse side contains the Regiomontanus-type arrangement. The missing plumb bob arm suggests the instrument is incomplete.
- Documentation and History
- The instrument is currently held by the British Museum in London, identified under registration number MLA 1895, 3-19.2. It was acquired by the museum in 1895. The dial is documented in the publication 'A Catalogue of European Scientific Instruments in the Department of Medieval and Later Antiquities of the British Museum' by F. A. B. Ward, published in 1981. The date of manufacture is placed in the late 16th century, though this attribution is presented with uncertainty. The production origin is identified as French, based on the provided catalogue information.
- Inscriptions and Markings
- The instrument features several inscriptions and numerical markings. On the obverse, within the apex of the horary quadrant, is the Hebrew tetragram representing 'God'. The bottom section of this face includes the inscription 'Pour la Latitude de Paris 49', denoting the intended geographic utility of the dial. The Regiomontanus dial includes numerical scales for latitudes ranging from 5 to 60. Some of the numerical engravings on the rims are described as having potential discrepancies, with the source noting specific instances of apparent errors in the original sequence, such as '44 (recte 40?)' and '02 (recte 20?)'.
Identification
- Inventory number
- MLA 1895, 3-19.2
- 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 dating remains uncertain, indicated by a question mark in the documentation.
- Research required: Numerical markings on the instrument's side display potential errors, with source notations 'recte 40?' and 'recte 20?' suggesting inaccuracies in the original engraving.