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The Encyclopedia of Horology

Sèvres and Neuchâtel, Switzerland · 1861 – 1938

Charles Édouard Guillaume

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Metallurgy of nickel-steel alloys

Life & work

Charles Édouard Guillaume was a physicist whose work on nickel-steel alloys produced Invar and Elinvar, materials with very low thermal expansion and very low thermoelastic change respectively.

These alloys transformed precision timekeeping: Invar made pendulum rods far less temperature-sensitive, and Elinvar allowed hairsprings whose elasticity barely changed with temperature, largely removing the need for bimetallic compensation balances.

Training, contributions & innovations

  • Invar, which transformed precision pendulum construction
  • Elinvar, which allowed temperature-stable hairsprings
  • Awarded the Nobel Prize in Physics in 1920 for this metallurgical work

Inventions & patents

  • The alloy work is documented in the scientific literature and in patent records held by the institutions involved.

Signatures & markings on surviving work

  • Not a signing maker: his contribution appears in the materials used by others rather than in signed timepieces.

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.