In a message dated 96-08-06 03:19:53 EDT, you write: >Argon is best, has a low cathode fall, low ionization energy. Marcus, visually the results are impossible to differentiate, between Ne/Hg and A/Hg, but I suppose there may be a difference not detectable by eye. Instead of theorizing, why not measure? Doubt that the difference is as great as you suppose, but I'm still curious. Jeff