An attempt has been made to measure the energies with which positive ions arrive at the cathode of a negative point‐to‐plane corona in N2. A hairpin thermocouple was used as the point electrode. It was heated by the corona current, and its thermal emf was recorded by a galvanometer. After appropriate calibration, the potential across the Crookes darkspace was determined to be about 300 volts, and the average energy with which ions arrive at the corona point to be about 15 ev.