bright and vivid flash of fire, suddenly appearing in the atmosphere, and commonly disappearing in an instant, sometimes attended with clouds and thunder, and sometimes not. For an account of the phenomena of lightning, and of the opinions concerning it, see Electricity Index.

Artificial Lightning. Before the discoveries of Dr Franklin concerning the identity of electricity and lightning, many contrivances were invented in order to represent this terrifying phenomenon in miniature: the coruscations of phosphorus in warm weather, the ascension of the vapour of spirit of wine evaporated in a close place, &c. were used in order to support the hypothesis which at that time prevailed; namely, that lightning was formed of some sulphureous, nitrous, or other combustible vapours, floating in long trains in the atmosphere, which by some unaccountable means took fire, and produced all the destructive effects of that phenomenon. These representations, however, are now no more exhibited; and the only true artificial lightning is universally acknowledged to be the discharge of electric matter from bodies in which it is artificially set in motion by machines.

Lightning was looked upon as sacred both by the Greeks and Romans, and was supposed to be sent to execute vengeance on the earth: Hence persons killed with lightning, being thought hateful to the gods, were buried apart by themselves, lest the ashes of other men should receive pollution from them. Some say they were interred upon the very spot where they died; others will have it that they had no interment, but were suffered to rot where they fell, because it was unlawful for any man to approach the place. For this reason the ground was hedged in, lest any person unawares should contract pollution from it. All places struck with lightning were carefully avoided and fenced round, out of an opinion that Jupiter had either taken offence at them, and fixed upon them the marks of his displeasure, or that he had, by this means, pitched upon them as sacred to himself. The ground thus fenced about was called by the Romans bidentul. Lightning was much observed in augury, and was a good or bad omen, according to the circumstances attending it.