An electrochemical method has been developed for studying the Galvanic potential between two coexisting equilibrium phases of the molten (0.5 AgI + 0.5 NaCl) system. The method measures the electromotive force (emf) of a cell with two silver electrodes: Ag vertical bar x' AgI + (1 - x') NaCl vertical bar x '' AgI + (1 - x '') NaCl vertical bar Ag: The measurement was carried out from the melting point of the mixture to T = 1067 K to establish the Galvanic potential magnitude and its temperature dependency near the critical point of mixing. The behavior of the Galvanic potential in the vicinity of the critical temperature corresponded to those found for the interfacial tension between coexisting phases. (C) 2015 Elsevier Ltd. All rights reserved.