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:
“Nothing is quite so wretchedly corrupt as an aristocracy which has lost its power but kept its wealth and which still has endless leisure to devote to nothing but banal enjoyments. All its great thoughts and passionate energy are things of the past, and nothing but a host of petty, gnawing vices now cling to it like worms to a corpse.”
—Alexis de Tocqueville (1805–1859)
“Mutual repect implies discretion and reserve even in love itself; it means preserving as much liberty as possible to those whose life we share. We must distrust our instinct of intervention, for the desire to make one’s own will prevail is often disguised under the mask of solicitude.”
—Henri-Frédéric Amiel (1821–1881)