Will-o'-the-Wisp

The name says what it is. A wisp is a twist of straw, and a twist of straw lit at one end was the cheapest torch a traveller could carry. «Will-o'-the-wisp» therefore means «Will of the torch», by the same construction that makes «jack-o'-lantern» mean «Jack of the lantern». The marsh light was named by giving it a man's first name and the object that man would have to be holding. What makes it uneasy is that there is no hand.

Every district had its own. In England it was called hobby-lantern, Jenny-with-the-lantern and Peg-a-lantern; in Devon and Somerset, hinkypunk, and whoever got lost following it was said to be pixy-led. In Ireland it is Jack-o'-lantern, and it drags behind it a story that explains why it walks alone.

The Latin ignis fatuus, «foolish fire», sounds like an ancient name and is not: it is a term coined by German humanists in the sixteenth century which translates the vernacular Irrlicht, «misleading light». The Latin, that is, comes afterwards. And it is worth spelling out, because the two are often confused: Irrlicht is the German name of this light; Erlkönig is not. The Erlkönig is the alder-king of Goethe's ballad (1782), who kills a child in his father's arms, and has nothing to do with the marsh fire.

Witnesses agree on little and on the essential. A small flame, pale blue or greenish, floating low over standing water or peat; moving in jumps, advancing and drawing back; and shifting away as one approaches, always at the same distance, until whoever follows it is left in the mud with nothing to steer by.

The two descriptions that fixed the image in English are literary. Milton uses it in Paradise Lost (1667) to tell how Satan leads Eve to the tree: a wandering fire, compact of unctuous vapour, which (they say) some evil spirit attends, and which hovering and blazing with delusive light misleads the amazed night-wanderer from his way, to bogs and mires (book IX, lines 634-642). Before him, Shakespeare already treated the term as common knowledge: in Henry IV, Part 1 (act III, scene iii), Falstaff mocks Bardolph's burning nose by telling him he had taken it for an ignis fatuus or a ball of wildfire. It does not appear, on the other hand, in The Winter's Tale, which besides is not a poem but a comedy.

The traditional remedy was no charm. Whoever felt pixy-led was told to turn his coat inside out and keep walking. The physical explanation is old and still uncomfortable: gases of decay in the peat, methane together with phosphine, which ignites of itself in air; the mechanism is accepted, but reproducing in a laboratory a cold flame that travels remains hard.

It is not a death omen, and that is the line to draw. The light announces nothing: it does not say that anyone will die, nor who. What it does is show a path where there is none, and whoever drowns drowns for having followed it. To confuse it with the Irish banshee, who wails at the door of the house where there is to be a death, inverts the terms: the banshee warns of something that will happen anyway, whereas the light causes what would not have happened.

The one that does foretell is another, and much of the confusion comes from there: the Welsh canwyll corff, the corpse candle, a light that travels in advance the road the coffin will later take. They are alike in that both are solitary lights at night, and they differ in everything else, beginning with who dies and why.

What remains is the figurative use, still alive in English: to call a will-o'-the-wisp a goal that recedes as one advances toward it. Milton had already understood it so when he gave Satan the shape of a light that promises a road, and that is probably why the image outlived the chemical explanation.