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The Encyclopedia of Horology

Clock type · Specialist

Rolling Ball (Congreve) Clocks

Partially verified

Clocks regulated by a ball rolling down a zig-zag track on a tilting plate.

Movement & mechanism

  • A steel ball rolls down a track, taking a fixed time (e.g., 15 or 30 seconds)
  • At the end of the track, the ball trips a lever that tilts the plate in the other direction
  • The tilting action advances the gear train

Identification

  • Tilting brass plate with a zig-zag groove
  • Small steel ball visible moving across the plate
  • Usually housed under a glass shade

Terminology

  • Zig-zag track
  • Tilting plate
  • Interval timer

Known variations

  • Single and multi-ball versions

Collecting notes

Condition and originality are paramount. For technical clocks like regulators or atmospheric clocks, the completeness of the original mechanism is more important than case condition. For decorative clocks (Boulle, Empire), the quality of the case craft is central.

Related photographs

IGNATZ HOROLOVAR FLYING PENDULUM & FLIP CLOCKS
IGNATZ HOROLOVAR FLYING PENDULUM & FLIP CLOCKS — Invaluable auction archive, Auction archive photograph, rights review pending. Invaluable sold-lot record
Jerome & Co. flying pendulum novelty clock
Jerome & Co. flying pendulum novelty clock — Invaluable auction archive, Auction archive photograph, rights review pending. Invaluable sold-lot record

No confidently matched photograph of this subject has been found yet. These photographs show a closely related record, and are not examples of the type described on this page.

Sources & references

  1. Britten, F. J., Old Clocks and Watches and Their Makers
  2. Loomes, B., The Early Clockmakers of Great Britain
  3. Roberts, D., British Skeleton Clocks
  4. Museum catalogue records

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