Balance spring
From Wikipedia, the free encyclopedia
The balance spring is a device used in a mechanical watch to control the vibrations of the balance wheel.
There is some dispute as to whether it was invented by Robert Hooke or Christian Huygens, with the likelihood being that Hooke first had the idea, but Huygens built the first functioning watch that used a balance spring. See A. R. Hall, "Horology and criticism: Robert Hooke", Studia Copernicana, XVI, Ossolineum, 1978, 261-81.