The two unsymmetrical components of current to a collector in mercury vapor were separarely measured from the anode and the cathode directions. A collector taking current from both directions would receive the approximate sum of these unsymmetrical components. Sets of readings at different positions in an arc type of discharge show that both random electron currents and random positive ion currents are greater to the cathode face of the collector than to the anode face except in a region near the cathode where exactly the reverse is true. Determinations of space potentials and electron energies were not greatly affected by the asymmetry of the currents but determinations of electron concentrations were and the results indicate a region of maximum concentration from which positive ions and electrons may diffuse or drift in both directions. From a consideration of the rate of absorption of the primary beam a value of the mean free path is obtained and the region of maximum ionization appears at approximately this distance from the cathode.