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The Encyclopedia of Horology

Novelty regulator using a ball rolling down a zigzag tilting track as the escapement's timekeeping element · England

Congreve Rolling-Ball Clock (type)

Partially verified

An unusual escapement type in which a ball rolls along a grooved, tilting plate; when the ball reaches one end, the plate tilts the other way (driven by the clock's going train) and the ball rolls back, each traverse taking a set time.

Technical facts

Regulator
Ball rolling on a tilting zigzag-grooved plate
Typical period per traverse
Often around 30 seconds, varying by individual example

Historical significance

  • An unusual escapement type in which a ball rolls along a grooved, tilting plate; when the ball reaches one end, the plate tilts the other way (driven by the clock's going train) and the ball rolls back, each traverse taking a set time.
  • More a horological curiosity and engineering demonstration than a precision standard — accuracy is markedly inferior to a good pendulum clock, and this should be stated plainly rather than presented as a serious rival timekeeper.

Background

The Congreve clock, also known as Congreve's Rolling Ball Clock, is a specialized timekeeping device that regulates time by utilizing a ball rolling along a zigzag track. Designed by Sir William Congreve, the clock was patented in 1808 as an "Extreme Detached Escapement." Although Congreve was not a professional clockmaker, he commissioned Gravell & Tolkien to manufacture the first functional iteration of the design.

The clock functions by having a ball travel down a tilting tray, which trips an escapement to reverse the tray's angle while advancing the clock's hands. The mechanism is considered an unreliable timekeeper because the ball's travel speed is heavily influenced by the accumulation of dust on the horizontal track.

Written from the encyclopedia entries listed under Sources; each statement was checked against the cited text.

Construction and mechanism

  • Depending on the specific configuration, the second hand advances in 15 or 30-second increments during each oscillation.
  • The tray tilts once every few seconds, causing the clock hands to move forward up to four times per minute.

Later history

  • The first working version of the clock was presented to the Prince of Wales in 1808.
  • A second, spring-driven model of the clock is currently held in the collection of Buckingham Palace.

Photographs

Rolling ball clock
Rolling ball clock — Royal Museums Greenwich via Europeana, http://creativecommons.org/licenses/by-nc-sa/4.0/. Europeana record
Rolling ball clock in the British Museum
Rolling ball clock in the British Museum — Photograph by Mike Peel (www.mikepeel.net)., CC BY-SA 4.0. Wikimedia Commons file page
Rolling ball clock in the British Museum 1
Rolling ball clock in the British Museum 1 — Photograph by Mike Peel (www.mikepeel.net)., CC BY-SA 4.0. Wikimedia Commons file page
Congreve clock by Christoph Rohr, Braunschweig, 1600 AD - Herzog Anton Ulrich-Museum, gilt bronze, brass, steel - Braunschweig, Germany - DSC04546
Congreve clock by Christoph Rohr, Braunschweig, 1600 AD - Herzog Anton Ulrich-Museum, gilt bronze, brass, steel - Braunschweig, Germany - DSC04546 — Daderot, Public domain. Wikimedia Commons file page
Rolling ball clocks at Place Saint-Urcisse in Cahors 01
Rolling ball clocks at Place Saint-Urcisse in Cahors 01 — Krzysztof Golik, CC BY-SA 4.0. Wikimedia Commons file page
Congreve Rolling Ball Clock SOLD — Chalfont Clocks Repairs and ...
Congreve Rolling Ball Clock SOLD — Chalfont Clocks Repairs and ... — chalfontclocks.co.uk, Rights unverified — web image search result, review pending. Web page (chalfontclocks.co.uk)
English Congreve Rolling Ball Clock - Renaissance Antiques
English Congreve Rolling Ball Clock - Renaissance Antiques — Renaissance Antiques, Rights pending — source and visual checks completed; permission not yet requested. Web page (renaissanceantiques.com)
Antiques Atlas - Congreve Rolling Ball Clock
Antiques Atlas - Congreve Rolling Ball Clock — Antiques Atlas / Frank Craig Antiques, Rights pending — source and visual checks completed; permission not yet requested. Web page (antiques-atlas.com)

Photographs are illustrative examples of the type, not necessarily the exact object described. Verify details against the source file page.

Sources & references

  1. Congreve clock, Wikipedia (English), retrieved 2026-10-28 (text CC BY-SA 4.0)
  2. Antiquarian Horological Society, articles on Congreve's rolling-ball clock

Where sources disagree, the disagreement is stated rather than resolved silently.