Page:Popular Science Monthly Volume 43.djvu/472

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spent so much time and trouble. It was elaborately protected; protected by innumerable conductors with admirable earths made in a variety of ways, bristling with points all over the top—everything carried out in the most approved style, regardless of expense. Yet in the month of June the building was struck and set on fire.... If a lightning conductor can prevent a flash from occurring by its repellent action, well and good; but he had

PSM V43 D472 Multiple flash.jpg
Multiple Flash.

shown in his lectures that there are cases where a point has no protective action whatever, when a point could be struck by a thick and heavy flash. There were other cases where the point acts with a brush or fizz and neutralizes the electric charge without a flash. They could not always do it. And so the lightning rod has two functions; one is to be repellent if it can, and the other is to carry off a flash when it can not help receiving it.