Hi Rob,
I also watched thet programme on Tv last night, very interesting subject. I seem to recall through these poor old braincells watching a travel programme with Michael Palin in Africa, and down on the equator one of the native lads earned a few bob from tourists by showing them how the water changed direction using a bottle neck as a drain plug, then walking a short distance and the water reversed??, could have been a scam, but interesting discussion KT