Multiple lightning strokes

Multiple lightning strokes have long been known to exist, but so far instruments for recording the successive discharges on electric power lines have not been available. The application of expulsion protective gaps to 3 typical transmission lines, however, has made a partial investigation possible, with the aid of the automatic oscillograph. The results of this investigation are presented herewith. As many as 12 successive discharges have been recorded in a single stroke; these discharges have been as close together as 1 cycle (on a 60 cycle system) and as far apart as 9.5 cycles.