Moreover, while the eruptions from all volcanoes are intermittent-that is to say, every kind of volcano has alternating periods of activity and repose-the eruptions from geysers further differ from the fire and flame ejections of burning mountains, with their other attendant phenomena, in occurring at definite periods of time, and being of equally definite durations.
"A Girl's Ride in Iceland"
Ethel Brilliana Alec-Tweedie
We do not know, indeed, the rate of progress of the chronometer, but if the dial be one divided into eternal durations the consummation of any finite physical change represents such a movement of the hand as is accomplished in a single vibration of the balance wheel.
"The Birth-Time of the World and Other Scientific Essays"
J. (John) Joly
The periods between activity and rest, as well as the durations of the two processes, may be changed.
"Increasing-Human-Efficiency-in-Business-a-contribution-to-the-psychology-of-business"
Scott, Walter Dill