ABSTRACT
Lightning strokes can be of two kinds. In the first, a charged cloud induces a charge of opposite sign in nearby tall objects, such as towers, chimneys and trees. The electrostatic stress at the upper ends of these objects is sufficiently great to ionize the air in the immediate neighbourhood, which lowers the resistance of the path between the cloud and the object. Ultimately, the resistance is lowered sufficiently for a disruptive discharge to occur between them. This type of discharge is characterized by the time taken to produce it, and by the fact that it usually strikes against the highest and most pointed object in the area.
