From: nedlatham@internode.on.net   
      
   I was thinking about parallel-sided glass blocks, and their   
   fascinating demonstration of refraction of light on both   
   entry and exit, and it occurred to me that I've never seen   
   or heard anything about the beam itself except that it's a   
   little wider on exit than on entry.   
      
   So I wondered: has anyone ever looked at the exit beam in   
   sufficient detail to detect a spectrum or dismiss the idea?   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)