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

===Historical explanations===
The idea of the will-o'-the-wisp phenomena being caused by natural gases can be found as early as 1596, as mentioned in the works of [[Ludwig Lavater]].{{efn|"That many naturall things are taken to be ghoasts": "Many times candles & small fires appeare in the night, and seeme to runne up and downe... Sometime these fires goe alone in the night season, and put such as see them, as they travel by night, in great feare. But these things, and many such lyke have their naturall causes... Natural Philosophers write, that thicke exhilations aryse out of the earth, and are kindled. Mynes full of sulphur and brimstone, if the aire enter unto it, as it lyeth in the holes and veines of the earth, will kindle on fier, and strive to get out." From ''[[iarchive:ofghostesspirite00lava|Of Ghostes and Spirites, Walking by Night, And of Straunge Noyses, Crackes, and Sundrie forewarnings, which commonly happen before the death of men: Great Slaughters, and alterations of Kingdomes]]''.}}<ref>{{Cite book|url=https://archive.org/details/ofghostesspirite00lava|title=Of ghostes and spirites, walking by night: and of straunge noyses, crackes, and sundrie forewarnings: which commonly happen before the death of men: great slaughters, and alterations of kingdoms.|last=Lavatar|first=Ludwig|date=1596|publisher=Thomas Creede|others=Blough-Weis Library Susquehanna University|pages=[https://archive.org/details/ofghostesspirite00lava/page/51 51]–52}}</ref> In 1776 [[Alessandro Volta]] first proposed that natural electrical phenomena (like lightning) interacting with [[methane]] [[marsh gas]] may be the cause of ignis fatuus.<ref name="volta">{{cite book |first=Marco |last=Ciardi |editor1=Fabio Bevilacqua |editor2=Lucio Fregonese |title=Nuova Voltiana: Studies on Volta and His Times |chapter=Falling Stars, Instruments and Myths: Volta and the Birth of Modern Meteorology |publisher=Editore Ulrico Hoepli |year=2000 |page=43 |chapter-url=http://ppp.unipv.it/Collana/Pages/Libri/Saggi/Nuova%20Voltiana3_PDF/cap2/2.pdf}}</ref> This was supported by the British [[polymath]] [[Joseph Priestley]] in his series of works ''[[Experiments and Observations on Different Kinds of Air]]'' (1772–1790); and by the French physicist [[Pierre Bertholon de Saint-Lazare]] in ''De l'électricité des météores'' (1787).<ref name="tomlinson">{{cite journal|first=Charles|last=Tomlinson|year=1893|title=On Certain Low-Lying Meteors|editor=A. Cowper Ranyard|journal=[[Knowledge (magazine)|Knowledge: An Illustrated Magazine of Science. Simply Worded{{snd}}Exactly Described]]|volume=16|issue=New Series, Vol. III|pages=[https://archive.org/details/knowledgev140nov16londuoft/page/46 46]–48|url=https://archive.org/details/knowledgev140nov16londuoft |format=PDF}}</ref>

Early critics of the marsh gas hypothesis often dismissed it on various grounds including the unlikeliness of spontaneous combustion, the absence of warmth in some observed ignis fatuus, the odd behavior of ignis fatuus receding upon being approached, and the differing accounts of [[ball lightning]] (which was also classified as a kind of ignis fatuus).<ref name="tomlinson" /> An example of such criticism is found in ''Folk-Lore from Buffalo Valley'' (1891) by the American anthropologist [[John G. Owens]].{{efn|
"This is a name that is sometimes applied to a phenomenon perhaps more frequently called Jack-o'-the-Lantern, or Will-o'-the-Wisp. It seems to be a ball of fire, varying in size from that of a candle-flame to that of a man's head. It is generally observed in damp, marshy places, moving to and fro; but it has been known to stand perfectly still and send off scintillations. As you approach it, it will move on, keeping just beyond your reach; if you retire, it will follow you. That these fireballs do occur, and that they will repeat your motion, seems to be established, but no satisfactory explanation has yet been offered that I have heard. Those who are less superstitious say that it is the ignition of the gases rising from the marsh. But how a light produced from burning gas could have the form described and move as described, advancing as you advance, receding as you recede, and at other times remaining stationary, without having any visible connection with the earth, is not clear to me".}}<ref>{{cite journal |author=Owens J.G. |year=1891 |title=Folk-Lore from Buffalo Valley |journal=Journal of American Folk-Lore |volume=4 |pages=123–124 }}</ref>

The apparent retreat of ignis fatuus upon being approached might be explained simply by the agitation of the air by nearby moving objects, causing the gases to disperse. This was observed in the very detailed accounts of several close interactions with ignis fatuus published earlier in 1832 by Major Louis Blesson after a series of experiments in various localities where they were known to occur.<ref name="blesson">{{cite journal|first=Louis|last=Blesson|year=1832–1833|title=Observations on the Ignis Fatuus, or Will-with-the-Wisp, Falling Stars, and Thunder Storms|journal=The Edinburgh New Philosophical Journal|volume=14|pages=90–94|url=http://inamidst.com/lights/wisp/blesson1832}}</ref> Of note is his first encounter with ignis fatuus in a marshland between a deep valley in the forest of Gorbitz, [[Neumark|Newmark]], Germany. Blesson observed that the water was covered by an iridescent film, and during day-time, bubbles could be observed rising abundantly from certain areas. At night, Blesson observed bluish-purple flames in the same areas and concluded that it was connected to the rising gas. He spent several days investigating the phenomenon, finding to his dismay that the flames retreated every time he tried to approach them. He eventually succeeded and was able to confirm that the lights were indeed caused by ignited gas. The British scientist [[Charles Tomlinson (scientist)|Charles Tomlinson]] in ''On Certain Low-Lying Meteors'' (1893) described Blesson's experiments.{{efn|"On visiting the spot at night, the sensitive flames retired as the major advanced; but on standing quite still, they returned, and he tried to light a piece of paper at them, but the current of air produced by his breath kept them at too great a distance. On turning away his head, and screening his breath, he succeeded in setting fire to the paper. He was also able to extinguish the flame by driving it before him to a part of the ground where no gas was produced; then applying a flame to the place whence the gas issued, a kind of explosion was heard over eight or nine square feet of the marsh; a red light was seen, which faded to a blue flame about three feet high and this continued to burn with an unsteady motion. As the morning dawned the flames became pale and they seemed to approach nearer and nearer to the earth, until at last they faded from sight".}}<ref name="tomlinson" />

Blesson also observed differences in the colour and heat of the flames in different marshes. The ignis fatuus in Malapane, [[Upper Silesia]] (now [[Ozimek]], [[Poland]]) could be ignited and extinguished, but were unable to burn pieces of paper or wood shavings. Similarly, the ignis fatuus in another forest in Poland coated pieces of paper and wood shavings with an oily viscous fluid instead of burning them. Blesson also accidentally created ignis fatuus in the marshes of [[Porta Westfalica]], Germany, while launching fireworks.<ref name="tomlinson" /><ref name="blesson" />

====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>