Discussion on “the sphere gap as a means of measuring high voltage” (Peek), “the electric strength of air — V, the influence of frequency” (Whitehead and Gorton), and “sphere gap discharge voltages at high frequen

L. W. Chubb: These three papers presented under the auspices of the Electrophysics Committee are very interesting, and they add a gread deal to our knowledge of high-voltage phenomena. The paper on the sphere gap by Mr. Peek adds some valuable experimental data on the effect of barometric pressure on the gap voltages. The effect of temperature, however, as expressed in the empirical formula, seems to be a matter of assumption based on free-path and pressure, but not confirmed by experimental data. The inverse proportionality between breakdown voltage and absolute temperature may hold throughout the range of atmospheric temperatures, but the stream of negative electrons from hot metallic electrodes will possibly have a greater effect at high temperatures.