III. Polarization and Cathodic Protection^★

The mechanism of polarization of a galvanic couple is developed. By means of separate elements in an electric network, the roles of electrode potentials and of resistive-potential differences are demonstrated in polarization and cathodic protection. Several methods of showing the relation between polarizing current and galvanic-couple potential are discussed. The electrical conditions which determine the distribution of current flowing to a galvanic couple are defined. The use of the term "current density" in cathodic protection should be carefully qualified; otherwise, it may be meaningless.