I accidentally came across "Formulas and Tables for the calculation of Mutual and Self-Inductance, Rosa and Grover". The location is at http://www.g3ynh.info/zdocs/refs/Rosa-Grover1911/Contents.html#001. Godfrey Loudner _______________________________________________ Tesla mailing list Tesla@xxxxxxxxxxxxxx http://www.pupman.com/mailman/listinfo/tesla