Glossary/Foliot
Foliot
A foliot is a swinging bar with adjustable weights on the end. It was employed as the earliest mechanical time controller, used in conjunction with a verge escapement.
The bar is twisted first one way and then the other and its rate can be increased by moving the weights that are situated on the ends of the bar closer towards the centre. The term foliot was first used by Jean Froisart, the French chronicler, in 1369, and means 'to dance about madly'.