Fred wrote:
On Fri, 21 May 2010 09:48:30 +0100 (BST), "Dave Liquorice"
wrote:

Do the maths based on the height difference and density of water.

Whoosh.
I'm off to ask google!

It's approximately 0.1 bar per metre of height (10.2m = 1 bar).

This is why water barometers were never very popular - they need to be
about 11m tall!

Mike