Horary Quadrant by Girolamo della Volpaia
Record status
Individual type · partial
Period
1570
This brass horary quadrant, measuring 310 mm in radius, was produced by Girolamo della Volpaia in Florence in 1570. The instrument features a limb calibrated to 90 degrees, an Italian hours dial showing hours 9 to 24, a zodiacal calendar, and a shadow square incorporating a circular 'Tabula Solis motus'.
On the back, an iron mounting system with a plate, screw, and wing nut allows for inclination, though this appears to be a later addition as it obscures parts of the engraved face. Two scrolled block sights are fixed along the edge for topographical operations. The piece serves as both a timekeeping and a measuring instrument, reflective of the work produced by the Della Volpaia family of instrument makers active during the 16th century.
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
- 1570
- Type
- Italian quadrant
- Maker
- Girolamo della Volpaia
- Radius
- 310 mm
- Inscription
- Latin text describing the function and latitude
- Place recorded
- Italy
- Maker / attribution
- Girolamo della Volpaia
- Latitude Calibration
- 43 degrees
Design
- Visible features
- • Features two scrolled block sights along the long edge. • Includes a circular Tabula Solis motus within a shadow square. • Morning hours are engraved as smooth lines and afternoon hours as dotted lines. • Iron mounting hardware on the reverse obscures parts of the face engraving.
- Face and Engraving
- The face of the quadrant is constructed of brass and features a complex array of calibrated scales and diagrams. The outer limb is marked with a 90-degree scale, subdivided to 2 degrees. Adjacent to this are the halves of a zodiacal calendar, providing readings to 5 days and degrees. The primary functional area consists of an Italian hours dial for hours 9 through 24, distinguishing morning and afternoon hours through line styles. Integrated into the design are a shadow square and a 'Tabula Solis motus'. The shadow square is numbered in groups of three up to twelve, with each section subdivided into fifteen. An inscription in Latin denotes the latitude for which the device is calibrated, specifically 43 degrees. This inscription wraps around the design and concludes with the signature of the artisan and the date of manufacture.
- Origins and Signatures
- The quadrant is signed by Girolamo della Volpaia, a maker of instruments identified as the son of Camillo della Volpaia. The family was noted for their output of measuring instruments in 16th-century Florence. The instrument itself is specifically calibrated for the geographic conditions of Central Italy, covering regions such as Tuscany, Umbria, and upper Lazio, which confirms its localized utility for 1570. The piece is held in the collection of the Istituto e Museo di Storia della Scienza in Florence. The signature is placed directly on the face of the instrument, following the Latin inscription defining its topographical and chronometric capabilities. The object is officially catalogued under inventory number 239.
- Mounting and Mechanical Additions
- To the reverse side of the brass quadrant is attached an iron mounting system. This component consists of a plate riveted to the main body, featuring a screw and wing nut mechanism that supports a semi-circular piece. A spiked adjustment allows the instrument to be pivoted through a 90-degree range, providing various inclinations as required for its operation. Physical evidence suggests that this iron mounting was not part of the original design. The rivets used to secure the assembly to the back penetrate through to the front, breaking the existing engraving.
Identification
- Inventory Number
- 239
- 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 provenance of the iron mounting assembly suggests it is a later addition.
- Research required: The exact nature of the topographical operations supported by the shadow square is not specified beyond its presence.