Observations of the variation of precipitation electricity with height

Previous workers have found evidence of negative space charge in continuous rain and that the precipitation current was greater at a height of 30 m than at ground level. An investigation into these effects was carried out by making measurements of the precipitation current and potential gradient at the top of a mast and simultaneously at ground level. Unfortunately the investigation was brought to a premature end and the potential gradient measurements were rendered ambiguous through difficulties encoutered when calibrating the instrument to be on the mast. It was possible however to detect the presence of some space charge. The current at the top of the mast was found to be several times greater than that at the ground and their variations did not correspond exactly, suggesting that some charging process was operating in the lower 30 m of the atmosphere.