Scaphe Dial by Alexander Ravillius
Record status
Individual type · partial
Period
1538
This scaphe dial is a 16th-century horological instrument crafted from ivory, measuring 90 mm in diameter. Attributed to the maker Alexander Ravillius, the instrument dates to 1537.
It consists of a turned ivory box designed to house two distinct components for timekeeping and surveying. The lid contains a magnetic compass featuring a scale of degrees and Mediterranean wind initials, set against painted and gilt foliate decoration. Sights cut into the ivory rim allow for use as a surveyor's cross. The base of the instrument contains a hemispherical scaphe sundial with a central pin-gnomon mounted in brass.
This dial utilizes Italian hours, with the hour lines numbered 9 to 23. A small, glazed magnetic compass is integrated into the bottom of the hemisphere. The instrument is further inscribed with its latitude of 45 degrees and includes decorative engravings reflecting the sun's path through the zodiac.
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
- 1537
- Type
- Italian scaphe dial
- Maker
- Alexander Ravillius
- Latitude
- 45 degrees
- Material
- Ivory
- Hours system
- Italian hours
- Place recorded
- Italy
- Maker / attribution
- Alexander Ravillius
Design
- Visible features
- • Ivory housing shows structural cracks at the cardinal point sights. • Brass band reinforces the exterior rim of the lid. • Pin-gnomon is mounted in the center of a hemispherical concave surface. • Magnetic needle is situated above a gilt and painted floral pattern.
- Construction and Design
- The instrument is constructed as a turned ivory box, measuring 90 mm in diameter. Its primary function is dual-purpose, serving both as a timepiece and a surveying tool. The design incorporates two primary sections: the lid and the base. The base contains a hemispherical, concave dial surface, while the lid serves to protect the instrument and provide additional functionality. The interior of the base is engraved with hour lines numbered 9 to 23, with the line for the 24th hour positioned on the rim. The layout includes lines representing the sun's path between the tropics, marked with zodiac symbols on the rim. A meridian line extends from the interior into the rim, serving as a constant reference for the dial's orientation.
- Signatures and Preservation
- The instrument bears a signature and date on the rim, inscribed as 'RAVILLIVS M.D.XXXVIII'. This corresponds with the attribution of the dial to Alexander Ravillius. The rim also displays the latitude for which the dial was calculated, indicated as 'POLVS G.45'. The ivory components have sustained physical wear over time. Specifically, the slit sights used for surveying have caused open cracks in the ivory rim. To stabilize the structure, a brass band has been applied around the rim. The current condition is documented by the Museum of the History of Science, which holds the object in its collection.
- Integrated Surveying and Orientation Tools
- The lid of the instrument functions as a magnetic compass and surveyor's tool. The compass needle is mounted above painted and gilt foliate decoration. The compass circle is divided into eight winds, marked with specific initials, and further subdivided into sections of five degrees. A glass cover is secured by a brass ring to protect the needle and scale. Slit sights are cut into the ivory rim at the cardinal points, allowing the lid to function as a surveyor's cross. When paired with the compass, these allow the user to measure magnetic bearings. At the base of the hemispherical dial, a small, glazed magnetic compass provides an additional reference for orienting the sundial correctly.
Identification
- Inventory number
- 36708
- 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: There is a discrepancy in the date provided by the source: 'Dated 1537' appears in the header while the signature on the rim is transcribed as 'M.D.XXXVIII' (1538).
- Research required: The function of the brass band as a contemporary or later repair is not explicitly stated.