A phosphorescent light that appears, in the night, over marshy ground, supposed to be occasioned by the decomposition of animal or vegetable substances, or by some inflammable gas; popularly called also Will-with-the-wisp, or Will-o'-the-wisp, and Jack-with-a-lantern, or Jack-o'-lantern. It is thought by some to be caused by phosphine, PH3, a sponaneously combustible gas.
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