"a region electric and wild where strange shapes of soft blue fire ran over the metal of the horses’ trappings and the wagonwheels rolled in hoops of fire and little shapes of pale blue came to perch in the ears of the horses and in the beards of the men"
Illustration of St. Elmo’s Fire appearing on masts of ship at sea
Public DomainIllustration of St. Elmo’s Fire appearing on masts of ship at sea - Credit: The Aerial World

This is a description of a weather phenomenon known as St. Elmo’s Fire, a bright blue or violet glowing light, sometimes resembling fire in appearance, caused by the ionization of the air during thunderstorms inside of a strong electric field.

It is usually spotted upon tall, sharply pointed structures such as lightning rods, masts, spires and chimneys, as well as on aircraft wings. It has also been recorded appearing upon leaves, grass, and even at the tips of cattle horns.

It is named after the patron saint of sailors Erasmus of Formiae (also known as St. Elmo) since the phenomenon sometimes appeared on ships at sea during thunderstorms.