The Effects of Thunderstorms and Lightning Discharges on the Earth's Electric Field

This paper discusses the results of a series of observations of the potential gradient near the ground during thunderstorms. The recording instrument is intermediate in speed between the ordinary methods used for recording the potential gradient in fine weather and the high-speed oscillographs employed for detailed study of the variation of the field during short intervals of time. It yields a continuous record of the potential gradient and will also follow fairly rapid changes, the limit being set by the time of response of the electrometer which is less than 0.05 sec. The records thus yield information which would be missed by slower or by very rapid recording instruments. The observations extended over the years 1926—36 and were mostly made during the summer months.