'Sinking bowl' water clock, Saxon.
© Science Museum / Science & Society Picture Library
This is a replica of the original bronze bowl found in a bog in County Antrim, Northern Ireland. It is of the type which was employed by the Ancient Britons, probably under the influence of the Druids, for measuring intervals of time. The bowl has a small hole in the bottom, and in use it was placed on the surface of water, which slowly leaked into it until, after a certain interval of time, the bowl sank. The interval was the unit of time; in the case of this bowl, approximately one hour.