=St. Elmo’s Fire.=--A much more authentic and, at the same time, very interesting form, under which the electricity of the clouds sometimes manifests its presence, is known by the name of St. Elmo’s fire. This phenomenon at one time presents the appearance of a star, shining at the points of the lances or bayonets of a company of soldiers; at another, it takes the form of a tuft of bluish light, which seems to stream away from the masts and spars of a ship at sea, or from the pointed spire of a church. It was well known to the ancients. Cæsar, in his Commentaries, tells us that, after a stormy night, the iron points of the javelins of the fifth legion seemed to be on fire; and Pliny says that he saw lights, like stars, shining on the lances of the soldiers, keeping watch by night upon the ramparts. When two such lights appeared at once, on the masts of a ship, they were called Castor and Pollux, and were regarded by sailors as a sign of a prosperous voyage. When only one appeared, it was called Helen, and was taken as an unfavorable omen. In modern times St. Elmo’s fire has been witnessed by a host of observers, and all its various phases have been repeatedly described. In the memoirs of Forbin we read that, when he was sailing once, in 1696, among the Balearic Islands, a sudden storm came on during the night, accompanied by lightning and thunder. “We saw on the vessel,” he says, “more than thirty St. Elmo’s fires. Among the rest there was one on the vane of the mainmast more than a foot and a half high. I sent a man up to fetch it down. When he was aloft he cried out that it made a noise like wetted gunpowder set on fire. I told him to take off the vane and come down; but, scarcely had he removed it from its place, when the fire left it and reappeared at the end of the mast, so that it was impossible to take it away. It remained for a long time, and gradually went out.” On the 14th of January, 1824, Monsieur Maxadorf happened to look at a load of straw in the middle of a field just under a dense black cloud. The straw seemed literally on fire--a streak of light went forth from every blade; even the driver’s whip shone with a pale-blue flame. As the black cloud passed away, the light gradually disappeared, after having lasted about ten minutes. Again, it is related that on the 8th of May, 1831, in Algiers, as the French artillery officers were walking out after sunset without their caps, each one saw a tuft of blue light on his neighbor’s head; and, when they stretched out their hands, a tuft of light was seen at the end of every finger. Not infrequently a traveler in the Alps sees the same luminous tuft on the point of his alpenstock. And quite recently, during a thunderstorm, a whole forest was observed to become luminous just before each flash of lightning, and to become dark again at the moment of the discharge.[12]