For ages the inhabitants of the globe have seen the lightning flash and heard the thunder rattle; and some writers upon the occult sciences of the ancients, as Salverte, have supposed that, tutored by experience, without any understanding of the theory of the subject, they possessed the secret of warding off from their buildings the thunderbolt by a conducting apparatus. It is certain that extraordinary intimations to this effect may be culled from their writings. Pliny states that Tullus Hostilius, practicing Numa’s art of bringing down fire from heaven, and performing it incorrectly, was struck with lightning—a fate which Professor Richman of St. Petersburg experienced, while performing incautiously the sublime experiment of Franklin, measuring the strength of the electricity brought down by a metallic rod in a thunder-storm, being instantly killed. Pliny likewise mentions the laurel as the only earthly production which lightning does not strike; hence, as a protection, these trees were planted around the temple of Apollo. Columella, however, mentions white vines surrounding the house of Tarchon, the Etruscan, for the same purpose. These expedients may provoke a smile without deserving one; for there can be no doubt that trees sufficiently high around a temple, or succulent plants covering a dwelling, will exercise to some extent a protective power, and act as a regular system of conductors. Salverte mentions several medals which appear to have reference to this subject, particularly one which represents the temple of Juno, the goddess of the air, the roof of which is armed with pointed rods. He quotes also Michaelis, upon the temple of Jerusalem, to show that the Jews were not unacquainted with the art of protecting their public buildings—a position grounded upon the following facts: “1. That there is nothing to indicate that the lightning ever struck the temple of Jerusalem during the lapse of a thousand years.” This, of course, does not make the fact certain; but when, as M. Arago justly remarks, we consider how carefully the ancient authors recorded the cases in which their public buildings were injured by lightning, we may accept the silence observed respecting the temple of Jerusalem, as proof that it was never struck. For three centuries the cathedral of Geneva, the most elevated in the city, has enjoyed a similar immunity, although inferior buildings have been repeatedly damaged. Saussure discovered the reason of this, in the tower being entirely covered with tinned iron plates, connected with different masses of metal on the roof, and again communicating with the ground by means of metallic pipes. “2. That according to the account of Josephus, a forest of spikes with golden or gilt points, and very sharp, covered the roof of this temple; a remarkable feature of resemblance with the temple of Juno represented on the Roman medals. 3. That this roof communicated with the caverns in the hill of the temple, by means of