Plate 25. 'The Ignis Fatuus' / in the Book, "Phenomena of Nature" [cover title]: 'Thirty plates illustrative of natural phenomena etc. with a short description annexed to each plate' [title page]. - / [illustrations] by Whimper [Josiah Wood Whymper, 1813-1903]; printed by R [Richard] Clay, Bread Street Hill. - London: SPCK etc, 1849. - Engravings, wood, coloured, in bound volume, 35x29x1cm.

Detail from an engraving by Whymper, plate 25 from 'Phenomena of Nature', published in London in 1849 for the Society for Promoting Christian Knowledge. 'In marshy and boggy places, a light is sometimes seen to hover over the ground by night, appearing from a distance like a taper gleaming from some cottage window. The light is caused by the lighting up of an inflammable gas produced by decaying animal and vegetable matter in bogs, marshes and stagnant pools. It is found that when damp soils are drained, the Will-o'-the-Wisp disappears.'