In old British folklore, a will-o’-wisp, or ignis fatuus (“fool’s fire”), was said to be an ethereal light seen by travelers at night, especially over bogs, swamps, or marshes. The phenomenon is known in countless different European tales by a variety of names, such as “friar’s lantern”. Of course, they have been spotted all around the world.
Will-o’-the-wisps are often thought to be blue-ish lights that drift over boggy landscapes. When these eerie orbs are seen in graveyards they are called corpse lights. In the 19th century Denham Tracts these were known as “ghost candles”. They were also referred to as “hobby lanterns” at that time. As part of this, in Wales, the light was thought to predict a funeral that would soon take place in the locality.
People say that if you ever get too close to the will-o’-wisps that they just disappear, which is why many people claim that they are conscious beings. Folklore and urban legends often attribute will-o’-the-wisps to ghosts, fairies, and elementals, among other kinds of spirits. According to one legend, they are some kind of impish creatures who are out to mislead travelers.
A will-o’-wisp is said to mislead travelers by resembling a flickering lamp. For instance, in Welsh folklore, it is said that the light is “fairy fire” held in the hand of a small goblin-like fairy that mischievously leads lone travelers off the beaten path. At night, as the person follows the “puca” through the marsh or bog, the fire in their hand is extinguished, leaving the traveler lost in the dark.
Some people believe that will-o-wisps are the lingering souls of the dead, which are neither too good for Heaven or too bad for Hell. While others believe there is only one such being. Will-o’-the-Wisp, they claim, is a tormented specter who takes out his frustration on the living by leading people to their doom.
As the tale is told in Shropshire, a man named Will Smith was an evil old blacksmith who was given a second chance by Saint Peter, but he was so vile that he ended up being doomed to wander the earth. The Devil even provided him with a lump of single burning coal with which to warm himself. Will then used it to lure foolish travelers to their death.
So, in England, will-o’-wisp meant “Will of the wisp”, just as the term jack-o’-lantern meant “Jack of the lantern”, in Ireland. Of course, this phenomenon is not at all confined to the British Isles. Notable will-o’-the-wisps include the Marfa lights of Texas, St. Louis Light in Saskatchewan, the Hessdalen lights in Norway, and the Naga fireballs on the Mekong in Thailand.
Here in New England, as well, the swampy area of Massachusetts known as the Bridgewater Triangle has folklore of ghostly orbs of light, and there are still sightings in the area to this very day. The thing is, what are they? Well, as many suspect, rather than being anything supernatural, will-o’-the-wisps may just turn out to be the result of spontaneous combustion.
Natural lights are likely caused by certain mixtures of gases reacting with atmospheric oxygen. These mixtures consist of things like methane, carbon dioxide, and, most notably, compounds containing phosphine. These creepy swamp gases can be produced in marshes and cemeteries, by bacteria living in the soil and breaking down organic matter. So, when bubbles of gas make it to the surface, poof a will-o’-the-wisp appears.
They could turn out to be nothing more than clouds of glowing gases. For instance, an experiment published in 1980 showed that you get a sort of glowing green cloud if you mix crude phosphine and methane. Since these reactions are pretty short-lived, it even explains why the spooky lights seem to disappear if you approach them. The apparent retreat of ignis fatuus upon being approached might be accounted for by the agitation of the air, causing the gases to disperse.
So, presumably, if will-o’-the-wisps are some sort of natural phenomena such as bioluminescence or chemiluminescence, then they would likely just be the result of photon emissions caused by the oxidation of things like phosphine and methane produced by organic decay. Thus, in some strange way, death is always involved in the dazzling spectacle. Ultimately though, no one really knows for sure.