Replica of bronze Saxon 'sinking bowl' water clock, Science Museum, South Kensington, London, 1931. Original made 750-850CE. Placed on the surface of water, it measures a unit of time (in this case approximately 1 hour) through a hole in the bottom which slowly allows water into it.

This is a copy of the original bronze bowl found in a bog in County Antrim, Northern Ireland. The bowl has a small hole in the bottom, and in use it was placed on the surface of water until, after a certain interval of time, it sank. The interval in the case of this bowl is approximately one hour.