English Brass Nocturnal

Technical characteristics

Date

16th century

Type

English nocturnal

Maker

Unsigned

Origin

England

Dimensions

77 mm in diameter

Provenance

Bequest of Sir Robert Dudley (1649) to the Grand Duke of Tuscany

Place recorded

England

Design

Visible features

• Two concentric rings on a supporting arm • Twenty-four touch pins on the outer ring • Anti-clockwise 12-hour scale • Two central indexes of differing shapes

Provenance and Attribution

Although the instrument remains unsigned, it is attributed to English manufacture during the 16th century. Historical documentation links the object directly to the collection of Sir Robert Dudley, an English explorer and cartographer. Following his departure from England, his collection was moved to Italy, where it became part of a significant bequest to the Grand Duke of Tuscany in 1649. The nocturnal is currently preserved under inventory number 2500 within the collections of the Istituto e Museo di Storia della Scienza in Florence.

Central Indexes and Components

The center of the instrument is occupied by two indexes that pivot from the central boss. These indexes are constructed with distinct profiles: one terminates in a flat, pointed end, while the other features a square end that has been returned through 90 degrees. These specific shapes are necessary for the accurate alignment of the device during observational use, allowing the user to map the rotation of the constellations against the calendar scale provided on the inner ring. There is uncertainty regarding the historical integrity of these central indexes. The provided documentation suggests that these specific parts may not be original to the instrument, but rather later replacements. Additionally, the instrument is noted for having become separated from its parent assembly.

Structural Design and Scale Configuration

This nocturnal features a skeletal construction, distinct from the common solid-disc variety. It consists of two concentric rings mounted on a straight arm, which terminates in a hole used for suspension or attachment to a missing parent component. The outer ring is engraved on one side with an anti-clockwise double 12-hour scale (I to XII, I to XII). This unconventional layout is specifically designed to function in conjunction with the 24 touch pins positioned on the opposite side of the ring, which are arranged in a clockwise direction. Beneath these pins, on the inner edge, lies an unnumbered 360-degree scale. The interior of the instrument contains a second, free-rotating ring bearing a calendar scale. This scale is graduated to indicate the day of the month, though it lacks specific provisions for leap years. In the space between the month of March and the central boss, there is a complex arrangement including a subsidiary ring and a fourth, partially open ring. This fourth component is capable of independent rotation within the subsidiary ring and features a small notch cut at the center of its diameter, facilitating time-telling operations.

Identification

Inventory Number

2500

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.