Electrical phenomenon which causes the masts and rigging of a ship to glow eerily in thundery weather, and which is sometimes also seen around aircraft during storms. Not unnaturally such lights, which crackle with a noise as of burning twigs, have inspired awe in travellers at sea over the centuries. Seafarers agree that, if confined to the tops of masts, St Elmo's Fire is generally a good omen because it means that a storm is past its worst. If it comes down to the dec, however, it is more ominous, and if it surrounds the head of one of the crew this is a sure portent of the unfortunate man's death. St Elmo, incidentally, is the patron saint of Mediterranean seamen and is often indentified with St Erasmus, who died on board ship during a storm at sea but is said to have returned to the veseel in the form of a shining light to guide the vessel through the waves.