In this method acapacitanceis compared with a mutual inductance in a 1000‐cycle a.c. network. The secondary of themutual inductanceis in the telephone bridge circuit and carries zero current. By using a Wagnerground circuitthere is complete silence in the telephone at the balance point. When used as asubstitution methodtwo nearly equal condensers can be compared with each other with anaccuracythat is much greater than that of the resistances employed. The final balance is obtained by adjusting a small variableself‐inductancein series with the primary of the mutual inductance. For a given capacitance and frequency the value of this self‐inductance is directly proportional to thepower factorof the condenser, and the scale of this inductance can be calibrated toread directlythe value of the power factor.Vector diagramsare given to show the relations among the capacitance, power factor, and the inductances, and a fewtypical measurementsare recorded.