57 An apparatus and method is provided for measuring the continuity and resistance of electric circuits, particularly electric wire circuits due to galvanic currents. A constant current from a cell is passed through the electric circuit to be tested and through a reference resistor where the voltages are measured to derive the resistance of the circuit. The measured voltages are sensed with a converter converted to a resistance measurement and displayed. The presence of spurious voltages is compensated for by connecting a galvanic current storage capacitor in the circuit, passing a reference current through the reference resistor and the circuit and comparing the voltage across the reference resistor with the voltage across the circuit and storage capacitor to derive a resistance reading. The reading is converted to a digital display. The method and apparatus provides a quick, convenient means of testing blasting circuit continuity in the field in the presence of stray current caused by in-earth galvanic action.