Navicula Dial
Record status
Individual type · partial
Period
15th century ?
This brass navicula dial, inventory number 54358, represents an altitude sundial design known as the 'little ship of Venice'. The instrument measures 82 mm in width.
The primary body is shaped like a vessel with a castellated poop and forecastle that integrate double pinhole sights. A central vertical mast functions as a suspension for an adjustable plumb-line, which is missing from this example. The dial is unsigned and its geographic origin remains unknown. The instrument features a rectilinear altitude sundial on the front, accompanied by a zodiac arc for seasonal adjustment. The back of the instrument carries a shadow-square with specific scales and an unequal hour quadrant for converting time readings.
This piece is held by the Museum of the History of Science, Oxford.
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
- Navicula dial
- Width
- 82 mm
- Origin
- Unknown
- Material
- Brass
- Latitude Scale
- 20 to 65
- Date Attribution
- 15th century ?
- Shadow Square Scale
- 0 to 12 to 0
Design
- Visible features
- • Main body engraved with hour-lines shaped like a ship • Castellated poop and forecastle with pinhole sights • Vertical mast with sliding suspension point • Shadow-square with numerical scales on the reverse
- Attribution and Status
- The navicula dial is an unsigned object with no specific attribution to a maker or a workshop. The period of manufacture is suggested as the 15th century, though this is marked with a question mark, and the geographical origin of the device is currently listed as unknown. The instrument is part of the collection held at the Museum of the History of Science in Oxford, recorded under the inventory number 54358. Due to the lack of maker marks or historical context in the provided source, the dating remains purely speculative.
- Construction and Design
- The instrument is fashioned from brass and measures 82 mm across its widest point. Its design is based on the 'navicula' or 'little ship of Venice', which is a specific form of altitude dial. The body of the dial is engraved with hour-lines and shaped to resemble a ship, with castellated sections at either end representing the poop and forecastle. Each of these castellated ends contains a double pinhole sight to facilitate observations. The vertical component, termed the mast, is fitted with a sliding suspension point. This mechanism was designed to hold a plumb-line, which is presently missing. A suspension hook is attached to the upper extremity of the mast, providing a means of holding the instrument upright during use.
- Functionality and Scales
- The front face displays a rectilinear altitude sundial with hour-lines marked for hours and half-hours. A zodiac arc featuring the names of various constellations is positioned below the hour-lines to allow for the adjustment of the mast angle relative to the date. There is an unmarked declination scale located to the side of the hour-lines intended for the positioning of a bead on the plumb-line. The reverse side of the dial features a shadow-square with scales calibrated from 0 to 12 to 0. Additionally, an unequal hour quadrant is included on the back, allowing the user to convert time values obtained via the sundial into unequal or planetary hours.
Identification
- Inventory Number
- 54358
- 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 plumb-line is missing
- Research required: The date is speculative and marked with a question mark
- Research required: The place of manufacture is unknown