During stormy weather, a faint blue glow may be seen around the tips of elevated, pointed objects. The flame typically appears around the masthead or yardarms of sailing ships. It also has been observed, however, around the corners of skyscrapers, the ends of airplane wings, and the tops of church steeples, trees, towers, and even cow horns. Though a scientific phenomenon, the glow is popularly associated with a third-century Italian bishop.

The bishop Erasmus, whose name was corrupted into “Elmo,” was one of the patron saints of sailors. Those sailors who observed the tip of light on the masts of their ships believed it to be the manifestation of Elmo’s protection over them. The luminous flame accordingly became known as St. Elmo’s Fire.

St. Elmo’s Fire is the result of a steady electrical discharge from sharp, extended structures. Intense storm activity induces the discharge; when there is high voltage in the air beneath storm clouds, the negative charge on those clouds attracts an accumulation of positive charge at surrounding elevated points. (By principle, opposite kinds of electricity attract each other.) The phenomenon, which may be accompanied by a fizzing or crackling noise, is not dangerous, but sometimes is followed by a more troublesome discharge.

PostScript: It is believed that Erasmus was martyred during the persecution of Christians by Diocletian, the Roman emperor. According to legend, Erasmus was disemboweled, leading those who later suffered from intestinal illnesses to invoke his name.