== A pic: inertial circles == 

  I don't know if this helps, but I drew a picture of various inertial circles. The program to draw it (in IDL) is at http://www.antarctica.ac.uk/met/wmc/cor.pro. Disclaimer: done is a hurry, uses crude time-stepping, etc etc.  12:29:38, 2005-08-24 (UTC).