Power Reserve Indicator
Some high grade watches have an extra dial on the face indicating how much power is left in the mainspring, often graduated in hours the watch has left to run. Since both the arbor and the barrel turn, this mechanism requires a differential gear that measures how far the arbor has been turned, compared to the barrel.
Read more about this topic: Mainspring
Famous quotes containing the words power and/or reserve:
“Anyone who is kind to man knows the fragmentariness of most men, and wants to arrange a society of power in which men fall naturally into a collective wholeness, since they cannot have an individual wholeness. In this collective wholeness they will be fulfilled. But if they make efforts at individual fulfilment, they must fail for they are by nature fragmentary.”
—D.H. (David Herbert)
“Her face had the seamed reserve of the old in this country [Japan]. It was a neighborhood poignantly rich in old ladies.”
—Angela Carter (1940–1992)