Editing Will-o'-the-wisp (section)

====20th century====
A description of 'The Will-o'-the Wisp appeared in a 1936 UK publication of ''The Scout's Book of Gadgets and Dodges'',<ref name="Braham 1936 p54">{{Cite book |last=Braham |first=Sam F. |title=The Scout's Book of Gadgets and Dodges |publisher=The Scout |year=1936 |location=London |page=54 |language=English}}</ref> where the author (Sam F. Braham), describes it as follows:

<blockquote><nowiki/>'This is an uncertain light which may sometimes be seen dancing over churchyards and marshy places. No one really know how it is produced, and chemists are continually experimenting to discover its nature. It is thought that it is formed by the mixing of marsh gas, which is giving off decaying vegetable matter, with phosphoretted hydrogen, a gas which ignites instantly. But this theory has not been definitely proved.'<nowiki/><ref name="Braham 1936 p54" /></blockquote>
[[File:Glow worm lampyris noctiluca.jpg|thumb|Glowing firefly (''[[Lampyris noctiluca]]'')]]

One attempt to replicate ignis fatuus under laboratory conditions was in 1980 by British geologist Alan A. Mills of [[Leicester University]]. Though he did succeed in creating a cool glowing cloud by mixing crude phosphine and natural gas, the color of the light was green and it produced copious amounts of acrid smoke. This was contrary to most eyewitness accounts of ignis fatuus.<ref name="mills">{{cite journal|author=A. A. Mills|year=2000|title=Will-o'-the-wisp revisited|journal=Weather|volume=55|issue=7|pages=20–26|doi=10.1002/j.1477-8696.2000.tb04067.x|bibcode=2000Wthr...55..239M |s2cid=121340285 }}</ref><ref name="paleo" /> As an alternative, Mills proposed in 2000 that ignis fatuus may instead be [[Cool flame|cold flame]]s.<ref name="mills" /><ref name="garl" /> These are luminescent pre-combustion halos that occur when various compounds are heated to just below [[ignition point]]. Cold flames are indeed typically bluish in color and as their name suggests, they generate very little heat. Cold flames occur in a wide variety of compounds, including [[hydrocarbons]] (including methane), [[alcohols]], [[aldehydes]], [[oils]], [[acids]], and even [[waxes]]. However it is unknown if cold flames occur naturally, though a lot of compounds which exhibit cold flames are the natural byproducts of organic decay.<ref name="mills" /><ref name="nasa">{{cite book|url=https://books.google.com/books?id=BwKdl5NHALUC&pg=PA142|title=Cool Flames and Autoignition: Thermal-Ingnition Theory of Combustion Experimentally Validated in Microgravity|last=Pearlman|first=Howard|author2=Chapek, Richard M.|year=1999|publisher=[[NASA]]|page=142|isbn=978-1428918238}}, [http://www.grc.nasa.gov/WWW/RT/RT1999/6000/6711wu.html Web version at NASA] {{webarchive|url=https://web.archive.org/web/20100501223626/http://www.grc.nasa.gov/WWW/RT/RT1999/6000/6711wu.html |date=2010-05-01 }}</ref>
[[File:PanellusStipticusAug12 2009.jpg|thumb|''[[Panellus stipticus]]'', [[Mount Vernon, Wisconsin|Mt. Vernon, Wisconsin]] (long exposure)]]
A related hypothesis involves the natural [[chemiluminescence]] of phosphine. In 2008 the Italian chemists Luigi Garlaschelli and Paolo Boschetti attempted to recreate Mills' experiments. They successfully created a faint cool light by mixing phosphine with air and nitrogen. Though the glow was still greenish in colour, Garlaschelli and Boschetti noted that under low-light conditions, the human eye cannot easily distinguish between colours. Furthermore, by adjusting the concentrations of the gases and the environmental conditions (temperature, humidity, etc.), it was possible to eliminate the smoke and smell, or at least render it to undetectable levels. Garlaschelli and Boschetti also agreed with Mills that cold flames may also be a plausible explanation for other instances of ignis fatuus.<ref name="garl">{{cite book|author=Luigi Garlaschelli & Paolo Boschetti|title=On the track of the will-o'-the-wisp|publisher=Dipartimento di Chimica Organica, Università di Pavia|url=https://44cc653b-a-62cb3a1a-s-sites.googlegroups.com/site/luigigarlaschelli/WILLOWISexperiments.pdf?attachauth=ANoY7cpHRffGlOiCwYxPlrtxd2lTvwsEAMQGgBpRGfI7Y-FSRb5um5lKbRMP0MRniEcJQNazW1rv21_sSUv0z7rcprszClTsadRbFE9Xxy71H_KwKf664KGyQh4qSTmVURo7yIbcG-UcqktElznNxbFHiFZam7ecLQ5N84AxbnmVOkSFpPCDVt4dGztZ6nrMoge0hmnLMmTcRKu7R2IjvyKV2bpVc41_YKLiXIUHE12qr2wabmq33J8%3D&attredirects=0}}{{Dead link|date=August 2023 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>

In 1993 professors Derr and Persinger proposed that some ignis fatuus may be geologic in origin, [[piezoelectric]]ally generated under [[tectonics|tectonic]] strain. The strains that move faults would also heat up the rocks, vaporizing the water in them. Rock or soil containing something piezoelectric, like [[quartz]], [[silicon]], or [[arsenic]], may also produce [[electricity]], channelled up to the surface through the soil via a column of vaporized water, there somehow appearing as earth lights. This would explain why the lights appear electrical, erratic, or even intelligent in their behaviour.<ref>{{cite book|last=Persinger|first=Michael A.|author-link=Michael Persinger|title=Perceptual and Motor Skills|series=Geophysical variables and behavior: LXXIV. Man-made fluid injections into the crust and reports of luminous phenomena (UFO Reports)&nbsp;– Is the strain field an aseismically propagating hydrological pulse?|year=1993}}</ref><ref>{{cite book|last=Derr|first=J.S.|author-link=J.S. Derr|title=Perceptual and Motor Skills|series=Seasonal hydrological load and regional luminous phenomena (UFO reports) within river systems: the Mississippi Valley test.|year=1993}}{{page needed|date=December 2022}}</ref>

The will-o'-the-wisp phenomena may occur due to the [[bioluminescence]] of various forest dwelling micro-organisms and insects.  The eerie glow emitted from certain fungal species, such as the [[honey fungus]], during chemical reactions to form white rot could be mistaken for the mysterious will-o'-the-wisp or [[foxfire]] lights.  There are many other bioluminescent organisms that could create the illusions of fairy lights, such as [[fireflies]].  Light reflecting off larger forest dwelling creatures could explain the phenomenon of will-o'-the-wisp moving and reacting to other lights.  The white plumage of [[Western barn owl|barn owl]]s may reflect enough light from the Moon to appear as a will-o'-the-wisp; hence the possibility of the lights moving, reacting to other lights, etc.<ref>[http://www.owlpages.com/articles.php?section=Studies+and+Papers&title=Min+Min A Review of accounts of luminosity in Barn Owls ''Tyto alba''].</ref>

Ignis fatuus sightings are rarely reported today. The decline is believed to be the result of the draining and reclamation of swamplands in recent centuries, such as the formerly vast [[The Fens|Fenlands]] of eastern England which have now been converted to farmlands.<ref name="paleo">{{cite journal|first=Jan|last=Zalasiewicz|year=2007|editor=Richard Twitchett|title=The spirit of biodiversity|journal=The Palaeontology Newsletter|issue=64|pages=20–26|url=http://newsletter.palass-pubs.org/pdf/News64.pdf|archive-date=July 27, 2011|url-status=usurped|archive-url=https://web.archive.org/web/20110727184243/http://newsletter.palass-pubs.org/pdf/News64.pdf}}</ref>