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:
“O power of fantasy that steals our minds from things outside, to leave us unaware, although a thousand trumpets may blow loud—what stirs you if the senses show you nothing? Light stirs you, formed in Heaven, by itself, or by His will Who sends it down to us.”
—Dante Alighieri (1265–1321)
“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)