Characteristics
Physically, St. Elmo's fire is a bright blue or violet glow, appearing like fire in some circumstances, from tall, sharply pointed structures such as lightning rods, masts, spires and chimneys, and on aircraft wings. St. Elmo's fire can also appear on leaves, grass, and even at the tips of cattle horns. Often accompanying the glow is a distinct hissing or buzzing sound. It is sometimes confused with ball lightning.
In 1750, Ben Franklin hypothesized that a pointed iron rod would light up at the tip during a lightning storm, similar in appearance to St. Elmo's fire.
Read more about this topic: St. Elmo's Fire