The development of the spark discharge

Abstract The development of the short electric spark has been extensively studied by various scientists who used the Kerr electro-optical shutter, which enables the spark to be photographed at short intervals after its initiation. The longest sparks so studied have been of the order of a few centimetres, and the gap has usually been between parallel plate electrodes. The spark has been shown to start sometimes at the electrodes, and sometimes in the mid-gap region. The cloud chamber has also been used by others to study the pre-discharge and the spark between dissimilar electrodes and between parallel plate electrodes: between dissimilar electrodes the discharge generally starts from the smaller electrode: between parallel plate electrodes the same results were obtained as had been found by the Kerr cell technique. The rotating camera has been used by the authors to photograph the long electric spark and preliminary results have already been communicated (Allibone and Meek 1937; Allibone 1938). The present paper extends the results given in the two preceding papers.