1840
- Edouard Heuer, the founder of the watch manufacture Heuer, is born in Brügg, Canton of Bern, as Son of a shoemaker.
- Charles Weatstone, born in Gloucester, imagines the transmission of time using electro-chronometric counters.
- English engineer Bain builds a clock using electro-magnetic power.
- At the same time, English watchmakers Robert Molyneux and E.-J. Eiffe invent a balance wheel with auxiliary compensation for extreme temperatures, an idea also proposed by John Poole and Sir George Airy.
- Sir George Airy, director of the Greenwich Observatory, publishes an account of his experiments concerning the influence of terrestrial magnetism on the operation of chronometers.
1840 Louis Audemars in Le Brassus creates a pendant winding system. Similar systems are soon created by Breguet, Reymond-Bertaud, and Ad. Philippe in Paris, Ad. Nicole, a Swiss watchmaker established in London, Antoine LeCoultre in Le Sentier, and Sylvain Mairet in Le Locle.