Lightning Strokes

Abstract

MANY years ago I published a discussion of the origins of lightning discharges¹ which affirmed that a discharge would be expected to begin at a place of maximum electric force (not potential) and to bore its way through the atmosphere, without tearing it, initially along the direction of the force. I now add to this a theorem, due, I think, to Clerk Maxwell, that in an electrostatic field the force cannot be maximum anywhere in free space. It follows that discharges must be initiated, most probably at any rate, within the thunder-cloud. If the discharge begins from a conducting surface, similar reasoning would assign its origin to the more convex parts. As the moving camera of Sir Charles Boys has proved its efficiency in various hands in tracing the course of discharges, this theoretical conclusion may be useful in discussion of observations.