The polarity of thunderclouds

Abstract

The mechanism of the maintenance of the negative charge upon the surface of the earth has long been sought. C. T. R. Wilson has made the suggestion that the activity of thunderstorms of positive polarity—positively charged above and negatively charged below—will serve to separate positive and negative charges, by carrying negative charges to the earth and positive charges to the upper atmosphere. Experiments carried out by him during and subse­quent to 1916 indicated the presence of clouds predominantly of positive polarity, and similar experiments carried out by Schonland and Craib, in South Africa, gave similar conclusions. Appleton, Watt and Herd made observations on the form of atmospherics, and came to the conclusion that the thunderclouds which were the seat of the disturbances producing atmospherics were of positive polarity.