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:
“What I am anxious to do is to get the best bill possible with the least amount of friction.... I wish to avoid [splitting our party]. I shall do all in my power to retain the corporation tax as it is now and also force a reduction of the [tariff] schedules. It is only when all other efforts fail that Ill resort to headlines and force the people into this fight.”
—William Howard Taft (18571930)
“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 ones own will prevail is often disguised under the mask of solicitude.”
—Henri-Frédéric Amiel (18211881)