{i} device for measuring time which consists of two glass bulbs joined by a narrow passage through which a quantity of sand or mercury passes in one hour
It consists of a glass vessel having two compartments, from the uppermost of which a quantity of sand, water, or mercury occupies an hour in running through a small aperture unto the lower
An hourglass is a device that was used to measure the passing of an hour. It has two round glass sections linked by a narrow channel, and contains sand which takes an hour to flow from the top section into the lower one