IX. On the comparative efficiency as condensation nuclei of positively and negatively charged ions

Abstract

The work, of which the results are given in this communication, forms part of an investigation on atmospheric electricity, on which I am engaged on behalf of the Meteorological Council. The relation between rain and atmospheric electricity was one of the problems it was suggested I should study experimentally. The importance in connection with that question of the subject dealt with in this paper has already been noticed by Professor J. J. Thomson, who points out that ‘‘if the negative ions, say, were to differ in their power of condensing water around them from the positive, then we might get a cloud formed round one set of ions and not round the other. The ions in the cloud would fall under gravity, and thus we might have separation of positive and negative ions and the production of an electric field, the work required for the production of the field being done by gravity.”