The water clock

During the seventeenth century the water clock was no longer in widespread use in order to tell the time (imagine how much water it takes to turn a water clock for a week!), but was still used for precise time measurements. The water clock is made of a large container full of water, at the bottom of which is a pipe from which a thin stream of water spills into a glass. The same amount of water flows into the glass every second. By measuring the amount of water in the glass it is possible to measure how much time has passed.