I just came across a photo of a water filled sundial at Herstmonceux, England, but unfortunately there is no background information given. The photo is at http://www.ualberta.ca/~droles/astro/astrav/Sun2.html
I can not find any information about this dial on AltaVista or Yahoo. Can anybody provide me with some references explaining the history and principles of this dial? (preferably webpages) Thanks in advance, Steve