Two mechanisms have been proposed to account for the observed large yield of secondary electrons in gaseous breakdown at high electric fields. In one of these a single ion in approaching the cathode surface creates a ``pass'' by decreasing the width of the potential barrier. In the other the increased over‐all field due to a large number of ions in the gap is supposed to account for the increased emission. The first effect is re‐examined and appears to be effective in the observed breakdowns of extremely small gaps in air. It may also be effective in breakdown at high pressure and in liquid and solid dielectrics.