British bombing-plane crews reported on their return from a recent foray into Germany that at one point they encountered a storm which, without any display of lightning, cloaked their aircraft in a bright, blue, wavering glow. Wingtips, engine nacelles and the propeller blades sprouted thin fingers of sparks and the trailing aerials glowed as if they were white-hot. What the fliers were seeing was St. Elmo's Fire, a harmless but awe-inspiring phenomenon that occurs under certain atmospheric conditions and that used to strike terror to the bones of superstitious sailors.
St. Elmo's Fire occurs on both land and sea, when, in maintaining the balance of nature, accumulated electricity flows from the tip of some conductor, whether it be a church steeple or the mast of a ship, back into the atmosphere. It is visible only at night or in the blackness of a storm, and then only when the discharge if fairly heavy.
Up to a century ago little was known of the phenomenon, and accordingly sailors feared it as an ill omen if nothing else. Their most familiar name for it was "the corposant," and this term like the other derived from the Mediterranean. The name St. Elmo is supposed to be a corruption of St. Erasmus, via Sant' Ermo, St. Erasmus being the protector of travelers and the mysterious lights being the body of the saint, or corposant. Another name given it, when it was seen as a double corposant, was Castor and Pollux.
The electrical discharges have been reported in many forms—forked fingers, moving balls, wavering ribbons and drifting clouds. As time went on sailors got used to them, saw that they did not harm and were diverted by the displays. It was no less than laughable to see shipmates sprawled out on a yard arm fisting the sail while sparks and streamers outlined their heads. And to see a ball of pale blue fire stroll solemnly up the shrouds, out to the tip of the yard and then down to the deck in one bound, perharps to perch for a while on the oiled hat of some open-mouthed sailor, the wabble off along the scuppers, was more funny than frightening. A name that came into use in the latter days of the sailing ships was "williwalloo," the same name given to wavering, intermittent, catspaw winds.
The recorded history of these corposants and williwalloos goes back at least as far as Pliny, who thought they were stars come out of the heavens to guide sailors. Hakluyt wrote of them in 1598, saying they were much like candlelights, moving all over the ship for a space of three hours and sometimes appearing in two or three places at once. Burton in 1621 called them "fire-drakes," or celestial dragons. As late as 1710 a naturalist said the fires were caused by a "sulphureous spirit" and bituminous matter, ignited by agitation of the air. It is likely that Coleridge in "The Ancient Mariner" had reference to the phenomenon when he wrote:
The upper air bursts into life ;
And a hundred fire-flags sheen.