It is really difficult to understand how a man like Professor Arago could be misled into such false reasoning as this about an accident which, in itself, was of the simplest, and of the very easiest explanation. That the stroke of lightning falling upon Mr. Raven’s house, in Carolina, should have melted the wire of the conductor points to one cause, and to one only, namely, that there was no proper earth connection. Had it existed, the wire, although thin, could not possibly have been ‘melted all the part extending from the roof to the ground-storey,’ nor could the electric force have left its appointed path to seek a better one through a wall, and, still more astounding, ‘striking off at right angles.’ It is abundantly clear that such cases, and others to the same effect, brought against the fixing of lightning-conductors inside the walls of buildings, prove absolutely nothing. What is beyond controversy is, that a good conductor, in proper condition, is absolutely harmless to surrounding objects, including human beings. A man, even with a ‘fowling-piece’ in his hands, might lean full length against half-an-inch copper rod carrying off a heavy stroke of lightning into ‘good earth’ without so much as becoming aware of the passing of the electric discharge. If certainly a ‘grand seigneur,’ as Voltaire remarks, the electric force has this in common with some of the greatest of men, of not wasting its time, but following a clear aim. [Illustration: Fig. 31.] [Illustration: Fig. 32.]