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The Encyclopedia of Horology

Tool · Scientific instrument

Cary Portable Equinoctial Sundial

Partially verified

This brass portable equinoctial sundial is signed Cary, London and dates to circa 1820 according to the seller. Supported on a glazed compass base with three threaded knurled leveling screws and internal spirit levels, the instrument incorporates a silvered chapter ring engraved with Roman hour numerals and five-minute divisions. The hinged chapter ring connects to a curved latitude inclinometer arc and mounts a folding brass gnomon. The source reports that the dial assembly folds flat into an accompanying velvet-lined and leather-bound case.

Erected brass equinoctial sundial showing the chapter ring, gnomon, latitude scale, and compass base on leveling screws
Erected brass equinoctial sundial showing the chapter ring, gnomon, latitude scale, and compass base on leveling screws — 1stDibs. Rights pending — permission not yet requested. Original source

Catalogue identity

Source
www.1stdibs.com
Category
Tool · Scientific instrument
Maker / attribution
Cary, London
Reference
LU9752921779
Catalogue / lot identifier
f_921779
Source-reported date
circa 1820
Country
United Kingdom

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

Identity and Attribution

The instrument is identified by the inscription 'Cary, London' on the dial face. It is described as a portable equinoctial sundial.

The seller assigns a manufacture date of 1820 and attributes the object to the London instrument makers Cary.

Evidence for this section
  • “Portable Equinoctial Sundial Signed Cary, London”
  • “Date of Manufacture : 1820”

Construction and Dial Assembly

The sundial features a brass construction. The chapter rings are silvered and engraved with Roman numerals and five-minute increments.

A folding brass gnomon is mounted to the assembly. A curved latitude inclinometer is used to set the chapter ring angle, which rests in a slot on the side of the ring.

Evidence for this section
  • “The chapter rings are engraved and silvered.”
  • “chapters that are engraved in five-minute increments.”
  • “The brass pointer or gnomon is sprung and can be flipped perpendicular to the chapter ring”
  • “the inclinometer, which is hinged open and rests in a slot in the side of the chapter ring.”

Base and Leveling Mechanism

The dial assembly is supported on a compass base, which incorporates spirit levels to facilitate horizontal alignment. The base is leveled using three threaded feet.

The compass features a locking mechanism for the needle and is intended to be oriented toward north during use.

Evidence for this section
  • “The dial sits upon three threaded feet that are adjusted until the compass is exactly horizontal as indicated by the two spirit levels set at right angles to each other.”
  • “Once used, the compass needle is locked”

Documentation and Condition

The source describes an accompanying leather-bound, velvet-lined case secured with three brass hooks, though this item is not shown in the provided images.

The brass surfaces exhibit wear to the original lacquer.

Evidence for this section
  • “The dial folds into the original leather bound and velvet lined case that is secured with 3 brass hooks.”
  • “retains the original lacquer, though worn through on the areas that have received the most use.”

Open research questions

  • Are there archival records linking this specific reference number or serial description to Cary business records from 1820?
  • Does the engraving style of the chapter ring align with confirmed Cary workshop standards of the early 19th century?

Source evidence

Recorded claims and source quotations for Cary Portable Equinoctial Sundial
FieldSource-reported valueSource quotation
SignatureCary, London“Portable Equinoctial Sundial Signed Cary, London”
Date of Manufacture1820“Date of Manufacture : 1820”
Place of OriginEngland“Place of Origin : England”
Chapter Ring FinishEngraved and silvered“The chapter rings are engraved and silvered.”
GraduationsFive-minute increments“chapters that are engraved in five-minute increments.”
CaseLeather bound and velvet lined with three brass hooks“The dial folds into the original leather bound and velvet lined case that is secured with 3 brass hooks.”
Dimensions1.58 in Height, 5.52 in Depth“Dimensions : Height: 1.58 in (4 cm) Depth: 5.52 in (14 cm)”

Visible details

  • Silvered chapter ring engraved with Roman numerals from III to XII to IX and fractional graduations.
  • Graduated curved brass latitude arc marked with degree divisions up to 60.
  • Slender central gnomon standing upright across the center of the chapter ring.
  • Circular compass base housing a blued and silvered compass rose with at least one visible tube spirit level.
  • Base rim equipped with three outrigged threaded knurled leveling feet.

Research qualifications

  • Date of 1820 and original case are seller-reported details not independently verifiable from this photograph alone.
  • Case mentioned in source text is not depicted in this image.
  • Minor surface wear, patina, and tarnishing visible on brass surfaces.

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

Consulted source

Portable Equinoctial Sundial Signed Cary, London at 1stDibs

Reviewed 2026-10-25 · Record 6ab1401567

Terms in this record

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

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