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The Encyclopedia of Horology

Tool · French nocturnal and sundial

Nocturnal And Sundial

Partially verified

This gilt brass, 52 mm diameter instrument combines a nocturnal and a vertical disc sundial. It is unsigned and attributed to French manufacture circa 1600. The nocturnal face features an outer zodiac scale, a moveable ring divided into hours, a date scale, and a lunar volvelle with a scale for the age of the moon. It incorporates a small horizontal sundial with a folding gnomon and a compass box, although the needle is missing. The sundial face consists of a vertical disc dial with a pivoted index arm and a folding gnomon, accompanied by calendar and hour scales. Additionally, the instrument contains a volvelle on the sundial side that identifies favourable and unfavourable days of the year. The instrument is provided with an original shaped and lined leather case with brass fittings. The object is held in the collection of the Museum of the History of Science, Oxford.

The nocturnal side of the instrument showing the zodiac scale, moveable hour ring, and compass box.
The nocturnal side of the instrument showing the zodiac scale, moveable hour ring, and compass box. — Museum of the History of Science, Oxford. Rights pending — permission not yet requested. Original source

Catalogue identity

Source
www.mhs.ox.ac.uk
Category
Tool · French nocturnal and sundial
Maker / attribution
Not established
Reference
Not recorded
Catalogue / lot identifier
52632
Source-reported date
circa 1600
Source-reported place
France

Source-reported attribution and specifications are not independent authentication. A listing does not establish present ownership, current display, availability or permission to reproduce.

Object description

Nocturnal Face and Components

The nocturnal face comprises an outer zodiac scale inscribed with constellation names. Within this, a moveable ring is supported by two diametric bars and divided into 24 hour points. Beneath this ring sits a date scale with month names and numerical days, intended for use alongside the zodiac signs; the source notes that the first point of Aries corresponds to 20 March.

The face also includes a lunar volvelle with a scale representing the age of the moon from 1 to 29. A small horizontal sundial with a folding gnomon is positioned above the ring, alongside a circular compass box. While the compass lid pivots, the needle is currently missing from the instrument. An extended index arm, inscribed 'LIGNE DE FOY', facilitates the use of the nocturnal function.

Evidence for this section
  • “The nocturnal face has an outer zodiac scale with the names of the constellations”
  • “This face also incorporates a lunar volvelle, and the ring has a scale 1 to 29 for the age of the moon.”
  • “The needle is missing, but the cardinal points are marked 'O', 'M', 'O', 'S'.”

Sundial Face and Volvelle

The reverse side features a vertical disc sundial incorporating a pivoted index arm and a folding gnomon. The disc includes calendar scales with month abbreviations in French and a scale for ordinary hours marked in Roman numerals. The gnomon and index arm are attached to a central rotating disc designed for reading across circular scales.

This central disc features an inscription differentiating between 'les jours hereux' (favourable days) and 'les jours perileux' (unfavourable days). The scales are further marked with 'LE' or 'LEP' and 'L' or 'LP' followed by numbers. A cartouche on the instrument contains the sequence '15917', though its interpretation remains unresolved.

Evidence for this section
  • “The sundial face has a vertical disc dial, with a pivoted index arm carrying a folding gnomon.”
  • “One additional feature here is a volvelle on the vertical sundial side which advises the owner which days in the year are favourable - 'les jours hereux' - and which unfavourable - 'les jours perileux'.”
  • “A cartouche has the numbers 15917, so that it is unclear how to read this as a date.”

Provenance and Condition

The instrument is catalogued under inventory number 52632 at the Museum of the History of Science, Oxford. It is described as being more complete than a comparable instrument in the same collection (Epact 68501), specifically regarding the presence of the compass. The instrument is accompanied by its original shaped and lined leather case equipped with brass fittings.

The overall condition reflects the historical nature of the object, noting the absence of the compass needle and the ambiguous nature of the numeric inscription. The object is presented as an unsigned instrument, with its origins attributed generally to the French tradition of scientific instrument making at the turn of the 17th century.

Evidence for this section
  • “The example considered here is more complete, and shows that a small compass is missing from the other one.”
  • “With the original shaped and lined leather case with brass fittings.”
  • “Inventory number 52632”

Open research questions

  • What is the specific meaning or origin of the number 15917 inscribed within the cartouche?
  • Does the missing compass needle imply a specific repair history or typical loss for this type of instrument?

Source evidence

Recorded claims and source quotations for Nocturnal And Sundial
FieldSource-reported valueSource quotation
MaterialGilt brass“Gilt brass”
Diameter52 mm“52 mm in diameter”
OriginFrench“French”
Datecirca 1600“circa 1600 ?”
Compass markingsO, M, O, S“the cardinal points are marked 'O', 'M', 'O', 'S'”
Inventory number52632“Inventory number: 52632”
AccessoriesLeather case“original shaped and lined leather case with brass fittings”

Visible details

  • The instrument is suspended by a decorative handle with a shackle and ring.
  • The nocturnal side features an index arm engraved 'LIGNE DE FOY'.
  • A compass box is mounted on the nocturnal face with cardinal points marked 'O', 'M', 'O', 'S'.
  • The sundial face includes a volvelle for calculating favourable and unfavourable days.

Research qualifications

  • The date of origin is cited as 'circa 1600 ?', indicating uncertainty regarding its exact manufacture period.
  • The significance of the number '15917' found in a cartouche remains unclear.

Photograph identity and source facts were screened before import; rights clearance remains pending.

Consulted source

Nocturnal And Sundial

Reviewed 2026-10-26 · Record 63e17f8528

Terms in this record

Glossary explanations for terms named in this object’s record.

Other french nocturnal and sundial records