Skip to content
The Encyclopedia of Horology

London, United Kingdom · 1881 – 1971

William Hamilton Shortt

Verified

Free-pendulum precision clocks

Life & work

William Shortt, a railway engineer, developed the free-pendulum clock system in which a pendulum swings almost undisturbed while a slave clock performs the counting and display work.

Made with Synchronome, the system became the most accurate available before quartz standards, and installations served observatories internationally.

Training, contributions & innovations

  • The free-pendulum system, the most accurate mechanical timekeeping of its period
  • Enabled observatory timekeeping to detect small irregularities in Earth rotation

Inventions & patents

  • Patents exist for the free-pendulum arrangement; the specifications and Synchronome's records are the reliable sources.

Signatures & markings on surviving work

  • Not a signing maker in the traditional sense: instruments carry the Synchronome name and serial numbers.

Collecting significance

Signatures on historic work were applied by retailers and by later hands as well as by makers, so attribution should rest on the movement's construction and on documented provenance rather than on the name alone. A specialist opinion is worth obtaining before any purchase made on the strength of a signature.

Diagram

12345let downstripcleanoilregulateorder of work; never skip letting down the mainspring
Schematic: order of work at the bench. An outline schematic drawn to show the arrangement of the parts discussed here. It is not a dimensioned working drawing and does not depict a particular maker's calibre.

Sources & references

  1. Britten, F. J., Old Clocks and Watches and Their Makers
  2. Loomes, B., reference works on British and European clockmakers (edition-dependent)
  3. Museum catalogue entries for signed examples

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