The Quantum Theory of the Emission and Absorption of Radiation

Abstract

Emission and Absorption of Radiation. 243 (2) Observations have been made of the electric fields and field changes associated with 18 distant and 5 near thunderstorms. The sudden changes of field due to distant lightning discharges (> 8 km.) were predominantly negative in sign, those due to near discharges (< 6 km.) predominantly positive. The relative frequencies of positive and negative changes were 1 : 5 in the former case and 4 • 3 : 1 in the latter. The steady electric fields below the 5 near storms were all strongly negative. (3) It is shown that these results indicate that the thunderclouds were bi-polar in nature and that the polarity was generally, if not always, positive, the upper pole being positive and the lower pole negative. It is doubtful if any active storms of opposite polarity were observed at all. (4) The electric moments of the charges removed by 82 lightning discharges have been measured. The mean value is 94 coulomb-kilometres.