PHYSICS: C. BARUS ANODE AND CATHODE SPARKS DIFFERENTIATED BY THE MUCRONATE ELECTRODE By CARL BARus

Anode Points.-The present note is a continuation of the preceding (these PROCZEDINGS, 14, 1928, p. 50) in which the anode behavior was left outstanding. The method is the same (see Fig. 1), s in atm./106, denoting the wind pressure of positive ions when the needle of the electrode protrudes y cm. The spark gap x = 2 cm. is just within the power of the machine under the favorable circumstances (point discharge) given. As the sy anode graph rises more leisurely than the cathode graph, and as the convection current often strikes incidentally before the critical set is reached, experiments of the kind given heretofore are not satisfactory. I, therefore, ignored the critical set in favor of the initial sy graphs for the anode point in figure 3. The three curves (successively raised s = 20 for clearness) give much the same run of wind pressure s, when the extrusion y is increased from 0 to about 0.4 cm. The incidental and irregular jump of a convection pressure s to the cusp is indicated by vertical arrows. Its high value is not long sustained. Notwithstanding the straggling observations (resulting from the purring intermixture of convection current and spark succession), the slope of the graphs is highest when the cathode is earthed and.lowest when the anode is earthed. The latter graph starts from zero at a larger y. Thus for y = 0.12 cm. successive alternating observations gave