> Only 3 problems with front surface mirrors - expensive, hard to get, > and I don't think Archimedes had any. I strongly suspect that front surface mirrors were the only sort that Archimedes would have had available. What the that surface was made of is another matter :-) RM -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist