"Ewan Scott" wrote in message
...

"David Kemper" wrote in message
Hmm, what do you think causes this effect?

It could be as has been suggested wind, but I suspect it is more like
inertia. Honestly, I don't know. It isn't critical and I'm wishing I
hadn't
made the comment now :-)

grin I do that too! You say something and some clever dick comes along
and says prove it. You either have to justify what you said, which means
thinking about whether you are correct, or you can wriggle and waffle
and hope they get distracted by something else, or you can admit you
were wrong. Whichever choice you make you still learn something by
reconsidering that which you pronounced upon. (and no doubt believed to
be true.) Sometimes you have to change your beliefs.

David Kemper
Not a fan of wind.
Water sucks.