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The Encyclopedia of Horology

Tool · English astronomical compendium

Astronomical Compendium by Charles Whitwell

Partially verified

This astronomical compendium, attributed to the maker Charles Whitwell circa 1600, is constructed from an ivory box measuring 66 mm in diameter. It incorporates multiple functional components including a high-tide calculator, a lunar volvelle, a horizontal sundial, and a magnetic compass. The exterior lid features a tide-finding instrument with fixed scales and a volvelle. Internally, the lid holds a lunar volvelle with an engraved plate, an aspectarium, and a circular aperture for indicating moon phases. The lower section contains a horizontal dial equipped with a pierced, folding gnomon featuring decorative strapwork. A magnetic compass is set into the base, displaying a hand-painted compass card with thirty-two points. The name 'C Whitwell' is inscribed on the sundial hour ring. The object is held by the British Museum, London.

The ivory and gilt brass astronomical compendium open to show the dial, compass, and internal lunar volvelle.
The ivory and gilt brass astronomical compendium open to show the dial, compass, and internal lunar volvelle. — British Museum, London. Rights pending — permission not yet requested. Original source

Catalogue identity

Source
www.mhs.ox.ac.uk
Category
Tool · English astronomical compendium
Maker / attribution
Charles Whitwell
Reference
Not recorded
Catalogue / lot identifier
MLA 1854,1-3.1
Source-reported date
circa 1600
Source-reported place
London

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

Construction and Exterior Components

The compendium is constructed primarily from ivory, forming a circular box secured by a brass clasp. The exterior of the lid features an instrument specifically designed for calculating high tide at designated ports. This external mechanism consists of a fixed disc featuring two distinct scales and a central volvelle.

The outer scale is configured as an hour ring numbered twice from I to XII, while the inner fixed scale identifies sixteen compass points by their initial letters. The integrated volvelle includes a pointer and is inscribed with the age of the moon, calibrated from 1 to 29 1/2 days and divided into half-day increments.

Evidence for this section
  • “consists of an ivory box with an inset gilt brass instrument”
  • “Set into the top of the lid is an instrument for finding the time of high tide at particular ports”
  • “The volvelle with a pointer is inscribed with the age of the moon 1 to 291/2 days”

Internal Lunar and Horological Instruments

The interior lid houses a lunar volvelle comprising an engraved plate and two rotating discs, each equipped with an index. The plate displays two circular scales: one representing the Julian calendar with English month names and the other marked with Latin names for zodiacal signs, each subdivided into thirty-degree segments.

Within the base, a horizontal dial is mounted, featuring an hour ring marked with Roman numerals from IIII to XII to VIII. The time is indicated by a pierced folding gnomon, which features decorative strapwork. The base of the instrument also contains a magnetic compass with a painted card displaying thirty-two compass points and a 360-degree scale.

Evidence for this section
  • “Set into the inside of the lid is a lunar volvelle”
  • “A horizontal dial consisting of an hour ring and a pierced folding gnomon with pierced decorative strapwork is fixed”
  • “Set into the bottom itself is a magnetic compass with a painted beige compass card”

Signatures and Provenance

The compendium is inscribed with the signature of the maker, 'C Whitwell'. This inscription is positioned on the horizontal dial's hour ring, located between the markings for 4 a.m. and 8 p.m. This placement serves to identify the maker within the functional layout of the instrument.

The item was acquired by the British Museum in 1854 and is documented in the institutional literature, specifically within the catalogue of European scientific instruments compiled by F. A. B. Ward.

Evidence for this section
  • “The name of the maker 'C Whitwell' is inscribed between the lines for 4 o'clock a.m. and 8 o'clock p.m.”
  • “The instrument was purchased in 1854 and is described in F. A. B. Ward, A Catalogue of European Scientific Instruments”

Open research questions

  • What specific ports were intended to be used with the tide-finding instrument?
  • Does the painted compass card design correlate with other documented instruments by Charles Whitwell?

Source evidence

Recorded claims and source quotations for Astronomical Compendium by Charles Whitwell
FieldSource-reported valueSource quotation
MakerCharles Whitwell“Signed by Charles Whitwell”
Datecirca 1600“circa 1600; London”
Diameter66 mm“66 mm in diameter”
Registration NumberMLA 1854,1-3.1“Registration no. MLA 1854,1-3.1”
MaterialsGilt brass and ivory“Gilt brass and ivory”
Compass detailsPainted compass card with 32 points“painted beige compass card in yellow, orange and green. Thirty-two points are indicated”

Visible details

  • Ivory box construction with gilt brass insets
  • Pierced folding gnomon with decorative strapwork
  • Painted compass card in beige, yellow, orange, and green
  • Inscription 'C Whitwell' on the horizontal dial hour ring

Research qualifications

  • The exact date is given as circa 1600
  • Attribution to Charles Whitwell is based on the inscription

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

Consulted source

Astronomical Compendium

Reviewed 2026-10-26 · Record e401914060

Terms in this record

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

Other english astronomical compendium records