Mysterious phosphorescent lights often seen over marshes or in churchyards. They are also known as "fetchlights," "jack o'lanterns" and "dead men's candles," and are termed ignis fatuus. They are believed by some to presage death. The size is said to indicate the age of the victim, a small light representing an infant death, especially if it is a pale blue color.
These lights are erratic, sometimes disappearing and reap-pearing. They may be seen on or near the earth, in the air, or over lakes, or on the sea. They may be red, white, or blue and are thought to be caused by unusual atmospheric conditions, gaseous emanations, or by luminous insects.