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:
“The farmer imagines power and place are fine things. But the President has paid dear for his White House. It has commonly cost him all his peace, and the best of his manly attributes. To preserve for a short time so conspicuous an appearance before the world, he is content to eat dust before the real masters who stand erect behind the throne.”
—Ralph Waldo Emerson (1803–1882)
“I understood that all the material of a literary work was in my past life, I understood that I had acquired it in the midst of frivolous amusements, in idleness, in tenderness and in pain, stored up by me without my divining its destination or even its survival, as the seed has in reserve all the ingredients which will nourish the plant.”
—Marcel Proust (1871–1922)