THE NET ELECTRIFICATION OF NATURAL CLOUD DROPLETS AT THE EARTH'S SURFACE

Abstract

Samples of more than 35 natural clouds were passed through a special centrifuge and an ion filter in such a way that the free electricity on the droplets and on the air could be measured separately. The net charge on typical cloud droplets is less than one ion per droplet. This shows either that cloud droplets are not appreciably charged or that both positive and negative droplets are present and the distribution is such as to make the net charge very small. The measurements show that the capture of ions of a preferred sign by cloud droplets is not important.