Equinoctial Dial by Juan Cocart
Record status
Individual type · partial
Period
1596
This square equinoctial dial, held by the Museum of the History of Science in Oxford, is constructed from gilt brass and silver, measuring 11 by 43 by 44 mm. It features a folding hour circle marked 1 to 12 twice, mounted on a square base that incorporates a latitude adjustment arm.
The internal compass displays cardinal points in abbreviated form. Both the lid and the base of the box are engraved with latitude tables for sixteen locations. The object is signed by Juan Cocart and dated 1596. A later historical addition includes an engraved correction for magnetic deviation, signed by an individual named Ravizza and dated 1799. The instrument retains components that appear to be the original compass glass and needle.
The design shares structural similarities with other extant dials attributed to Cocart and the maker Petrus ab Aggere.
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
- 1596
- Type
- Iberian equinoctial dial
- Maker
- Juan Cocart
- Materials
- Gilt brass and silver
- Signature
- Juani Cocart me fe 1596
- Dimensions
- 11 x 43 x 44 mm
- Provenance
- Lewis Evans Collection
- Modification
- 1799 magnetic deviation correction by Ravizza
- Place recorded
- Spain
- Maker / attribution
- Juan Cocart
Design
- Visible features
- • Folding hour circle with double 1-12 numbering • Internal compass marked with cardinal points SE, OR, ME, OC • Latitude adjustment arm and scale ranging from 10 to 70 • Engraved 1799 magnetic deviation correction by Ravizza
- Construction and Design
- The equinoctial dial is housed in a square gilt brass and silver box. The instrument features a central compass protected by glass, with the cardinal points indicated by the letters 'SE', 'OR', 'ME', and 'OC'. A folding hour circle is situated above the compass, with the hours represented twice in a 1 to 12 sequence. The mechanism includes a brass arm for adjusting latitude, with a corresponding scale located on the side of the box, graduated every degree and numbered from 10 to 70. The outer lid and the base of the box are both engraved with tables listing latitudes for sixteen distinct locations. The interior of the lid is decorated with a geometric pattern, featuring two concentric circles in the central field and Tudor roses positioned within the spandrels of the square frame.
- Provenance and Preservation
- The object is currently part of the collection at the Museum of the History of Science in Oxford, specifically entering through the Lewis Evans Collection. The dial is documented as being in good condition, and the museum notes that the compass glass and needle appear to be original to the device. The dial is comparable to other known works by Juan Cocart and bears a resemblance to instruments produced by Petrus ab Aggere, another maker active in Spain.
- Signatures and Later Modifications
- The instrument bears the signature of its maker on the right edge of the box, reading 'Juani Cocart me fe 1596', which identifies the year of its manufacture. In 1799, the dial underwent a modification to correct for magnetic deviation. This intervention is recorded on the lower edge of the box via an inscription stating 'Ravizza correxit pro grad 26 m 10 , 1799'. This addition documents the continued use and maintenance of the dial two centuries after its creation.
Identification
- Inventory Number
- 51773
- 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 source notes the compass glass and needle appear original but does not confirm their state
- Research required: Attributions of maker similarity are provided as observations by the source rather than as technical certainty