I can assure it is not a threat! Anyone who wishes to continue with the discussion within this thread is quite welcome, including those who completely dissagree with me. But this virtual world is subject to the same rules and consequences as the real world. Commit slander as you have now done on more than one occasion in this thread and you take your consequences. I have never been concerned with people who dissagree with me. I object to those who have to resort to ad hominem as with the kid with the guitar, and I definitely will not accept unwarranted slander.

TonyL has got it about right and I couldn't do more than advice people to follow his thoughts if you wish to hear this effect. I am not sure who originated the work on non metalic cases, I think DNM and ourselves were working on parrallel lines about the same time in the early to mid 80's. I don't know of anyone prior to that. How does this happen, well you just need an open mind, where you always say "could be" instead of "can't". There are no absolutes in this world and the current state of the art leaves masses of possibilities.

Richard