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The Encyclopedia of Horology

Clock · Rolling ball clock

Dent Congreve rolling ball clock, no. 77

Partially verified

This Congreve rolling ball clock, designated number 77 and dated 1974, is attributed by the source to Dent, Robert Mackinnin. The timepiece features a single fusee movement fitted with a roll-over seconds indicator. Time is indicated across three silvered Arabic chapter rings marking hours, minutes, and quarter-minutes, equipped with blued moon hands. The open brass movement is supported by four turned columns resting on a brass plinth with an applied maker's plate. The clock base is mounted upon a tiered mahogany and green variegated marble foundation.

Front view of the Congreve rolling ball clock showing the three chapter rings, tilting track, brass columns, and marble base
Front view of the Congreve rolling ball clock showing the three chapter rings, tilting track, brass columns, and marble base — Bonhams. Rights pending — permission not yet requested. Original source

Catalogue identity

Source
www.bonhams.com
Category
Clock · Rolling ball clock
Maker / attribution
Dent, Robert Mackinnin
Reference
Not recorded
Catalogue / lot identifier
650
Source-reported date
1974
Country
Not established
Source-reported serial
no.77

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

Dial Arrangement and Time Indication

The timepiece incorporates three silvered Arabic chapter rings that register hours, minutes, and quarter-minutes, each equipped with blued moon hands.

Visual inspection confirms that these three circular dials are mounted across a brass frame positioned above the grooved tilting rolling ball table.

Evidence for this section
  • “three silvered Arabic chapter rings showing hours, minutes and quarter-minutes with blued moon hands”
  • “Three circular silvered chapter rings are positioned across a brass framework above the grooved tilting rolling ball table.”

Movement and Rolling Ball Mechanism

The listing records the mechanism as a substantial single fusee movement fitted with a roll-over seconds indicator, operating on the Congreve rolling ball principle.

Internal movement construction and escapement specifics beyond the fusee and seconds indicator are not detailed in the catalogue description.

Evidence for this section
  • “the substantial single fusee movement with roll-over seconds indicator”
  • “A Congreve rolling ball clock Dent, Robert Mackinnin, no.77, 1974”

Base Construction, Cover, and Attribution

The movement framework is supported by four turned columns resting on a plinth base fitted with an applied maker's name plate, standing on a mahogany and variegated marble base. Direct observation shows the plinth is brass, resting on a wooden tier and green veined marble base, with a triangular plaque marked 'DENT' affixed to the front.

The lot is catalogued under the heading 'Dent, Robert Mackinnin, no.77, 1974' and is noted as accompanied by a perspex case, measuring 49 cm wide, 37 cm deep, and 37 cm high.

Evidence for this section
  • “supported by four turned columns to a plinth base with applied maker's name plate”
  • “standing on a mahogany and variegated marble base with perspex case, wide 49cm, deep 37cm, high 37cm”
  • “A small triangular plaque marked 'DENT' is mounted on the front face of the brass plinth.”
  • “Dent, Robert Mackinnin, no.77, 1974”

Open research questions

  • What specific role did Robert Mackinnin play in the production or design of this 1974 clock attributed to Dent?
  • Where was the clock manufactured, given that no country of origin is recorded in the source?
  • Does the unillustrated perspex case have openings or specific mountings designed to seat onto the marble or mahogany plinth?

Source evidence

Recorded claims and source quotations for Dent Congreve rolling ball clock, no. 77
FieldSource-reported valueSource quotation
Maker and SerialDent, Robert Mackinnin, no.77, 1974“Dent, Robert Mackinnin, no.77, 1974”
MovementSubstantial single fusee movement with roll-over seconds indicator“substantial single fusee movement with roll-over seconds indicator”
Dials and HandsThree silvered Arabic chapter rings showing hours, minutes, and quarter-minutes with blued moon hands“three silvered Arabic chapter rings showing hours, minutes and quarter-minutes with blued moon hands”
Base ConstructionSupported by four turned columns to a plinth base with applied maker's name plate, standing on a mahogany and variegated marble base“supported by four turned columns to a plinth base with applied maker's name plate, the substantial single fusee movement with roll-over seconds indicator standing on a mahogany and variegated marble base”
DimensionsWide 49cm, deep 37cm, high 37cm“wide 49cm, deep 37cm, high 37cm”
Accompanying CoverPerspex case (unillustrated in the provided photograph)“with perspex case”
Auction ResultSold for £960 inc. premium on 10 June 2010 in Edinburgh“Sold for £960 inc. premium”

Visible details

  • Three circular silvered chapter rings are positioned across a brass framework above the grooved tilting rolling ball table.
  • The clock mechanism stands on a square brass plinth supported by four turned brass corner pillars, set onto a wooden tier and green veined marble base.
  • A small triangular plaque marked 'DENT' is mounted on the front face of the brass plinth.

Research qualifications

  • The perspex case mentioned in the catalog description is not shown in the image.
  • Specific country of origin is not explicitly stated in the listing text.

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

Consulted source

Bonhams : A Congreve rolling ball clock Dent, Robert Mackinnin, no.77, 1974

Reviewed 2026-10-21 · Record b6f4be6b25

Terms in this record

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

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