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The Encyclopedia of Horology

Marine chronometer · England

Thomas Earnshaw Marine Chronometers (representative series)

Partially verified

Earnshaw developed a simplified, more easily manufactured spring-detent escapement and bimetallic compensation balance, and his designs proved decisive in making marine chronometers producible in meaningful numbers rather than as individual bespoke instruments.

Technical facts

Escapement
Spring detent (chronometer escapement), Earnshaw's simplified form
Compensation
Bimetallic compensation balance
Case
Brass-bound wooden box with gimbal mounting, typical of marine chronometer practice

Historical significance

  • Earnshaw developed a simplified, more easily manufactured spring-detent escapement and bimetallic compensation balance, and his designs proved decisive in making marine chronometers producible in meaningful numbers rather than as individual bespoke instruments.
  • Earnshaw and John Arnold contested priority for several of these innovations during their lifetimes; as with the Arnold entry in this dataset, this is a representative production family rather than a single uniquely famous object, and any specific numbered example needs its own provenance research from the holding institution.

Related photographs

Description of the Le Roy detent escapement mechanism 14 August 1748
Description of the Le Roy detent escapement mechanism 14 August 1748 — Academie des Sciences, France 14 August 1748, Public domain. Wikimedia Commons file page
British Museum Marine Chronometer 1
British Museum Marine Chronometer 1 — Photograph by Mike Peel (www.mikepeel.net)., CC BY-SA 4.0. Wikimedia Commons file page
Diagram of the chronometer detent escapement Britten's Clock and Watchmaker's Handbook 9th Edition 1896
Diagram of the chronometer detent escapement Britten's Clock and Watchmaker's Handbook 9th Edition 1896 — F.J. Britten, Public domain. Wikimedia Commons file page

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. Betts, J., Arnold & Earnshaw: The Practicable Marine Chronometer (National Maritime Museum)

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