Anode melting caused by a d.c. arc discharge and its application to the determination of the anode fall

The power dissipated at the wire anode of a d.c. arc discharge (10 A) has been measured, for arcs in argon at atmospheric pressure, by noting the length of the anode which is melted. The heating of the anode is due to electrons accelerated by the anode fall, the heat energy of the electrons and the work function of the anode material. The measurement of the power transferred by the electrons if the electron energy and the work function are known gives rise to a useful means of determining the anode fall.