Formulas and tables for mutual inductance between parallel circuits with earth return

Existing formulas for the mutual inductance between parallel circuits with earth return, which are required for the calculation of interference, are either inadequate or difficult to apply in certain cases. The original formulas given by Carson have been modified and extended to give a more useful presentation in terms of the rectangular co-ordinates of the conductors, and Tables calculated by a computer are given for the ready application of the formulas.