Abstract :
A phenomenon is described which was observed during experiments with low-current arcs 0.1¿1 A. In these experiments, it was noted that the arc voltage experienced a substantial reduction in magnitude when the cathode was placed in a region of appreciable longitudinal magnetic field. With the cathode in very low magnetic fields, the arc voltage exhibited the behaviour characteristic of the Hoh and Lehnert effects and the Kadomtsev instability.