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:
“But, with whatever exception, it is still true that tradition characterizes the preaching of this country; that it comes out of the memory, and not out of the soul; that it aims at what is usual, and not at what is necessary and eternal; that thus historical Christianity destroys the power of preaching, by withdrawing it from the exploration of the moral nature of man; where the sublime is, where are the resources of astonishment and power.”
—Ralph Waldo Emerson (1803–1882)
“One should never make one’s debut with a scandal. One should reserve that to give an interest to one’s old age.”
—Oscar Wilde (1854–1900)