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:
“When power becomes gracious and descends into the visiblesuch descent I call beauty.”
—Friedrich Nietzsche (18441900)
“If a walker is indeed an individualist there is nowhere he cant go at dawn and not many places he cant go at noon. But just as it demeans life to live alongside a great river you can no longer swim in or drink from, to be crowded into safer areas and hours takes much of the gloss off walkingone sport you shouldnt have to reserve a time and a court for.”
—Edward Hoagland (b. 1932)