....500 years ago it was well known that the Earth was not flat... Certainly well-known to navigators... I suppose GPS, etc, has rendered such practical knowledge nugatory - I'm told the US Naval Academy no longer teaches Celestial Navigation. Perhaps our cousins in the RN are a bit more stuck in the mud... --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .