The Lightning Flash as Source of an Atmospheric

Abstract

DURING the last few years we have made, on the roof of King's College, London, a series of observations on the rapid variations of the earth's electric field associated with thundercloud discharges, using a Wilson sphere as the conductor exposed to the earth's field, and a cathode ray oscillograph, with photographic registration, as the recording instrument¹. In this way we have been able to follow the evolution of an atmospheric wave-form from the discontinuous change of field associated with near flashes to the type of radiation field, with its high-frequency detail, observed at greater distances. These experiments, together with allied investigations carried out at the Slough Radio Research Station of the National Physical Laboratory, were described at the recent meeting of the International Scientific Radio Union in London (September 1934).