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Will-o’-the-Wisp: an ancient
mystery with extremophile
origins?
Howell G. M. Edwards
rsta.royalsocietypublishing.org
Review
Cite this article: Edwards HGM. 2014
Will-o’-the-Wisp: an ancient mystery with
extremophile origins? Phil. Trans. R. Soc. A 372:
20140206.
http://dx.doi.org/10.1098/rsta.2014.0206
One contribution of 14 to a Theme Issue
‘Raman spectroscopy meets extremophiles on
Earth and Mars: studies for successful search
of life’.
Subject Areas:
biogeochemistry
Keywords:
will-o’-the-wisp, extremophiles,
stressed environments, analytical data,
in-field instrumentation
Author for correspondence:
Howell G. M. Edwards
e-mail: [email protected]
Centre for Astrobiology and Extremophiles Research, Chemical and
Forensic Sciences, School of Life Sciences, University of Bradford,
Bradford BD7 1DP, UK
This paper draws a comparison between the 700-yearold historically reported will-o’-the-wisp phenomenon
and the more recent discovery of extremophilic
colonization of hostile environments; both have
been observed as present in isolated, stressed
environmental regions and originating from biological
phenomena. However, whereas extremophilic activity
can be understood in terms of a survival strategy
based upon the synthesis of specific suites of
protective biochemicals which are designed to control
biogeologically the stressed habitats and to provide
protection against the extreme environments, the
analytical techniques that have proved so successful
for the illumination of these survival strategies of
extremophiles and which are now being miniaturized
for in-field studies and for extraterrestrial exploration
have not been applied to a clarification or evaluation
of the phenomenon of will-o’-the-wisp. The reason
is simply that the will-o’-the-wisp sightings have
now disappeared completely. Tantalizingly, all of
the most reasonable physico-chemical and biological
explanations for the will-o’-the-wisp phenomenon
proved to be unsatisfactory in some respect and it
is clear that, just as in the case of extremophilic
colonization, will-o’-the-wisp would benefit from a
modern rigorous analytical study which would
produce the data from which the potentially novel
biological behaviour could be characterized and
which would help a better understanding to be made
of our natural world.
1. Introduction
Extremophiles, which are defined as organisms that can
exist in isolated, stressed environments often where other
2014 The Author(s) Published by the Royal Society. All rights reserved.
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The will-o’-the-wisp conjures up a description of something rather elusive, mysterious and
ephemeral; however, historically, the phenomenon has been described by observers in the
literature of many countries and it clearly refers to a real event which was widely reported
by travellers in Europe and North America who were crossing treacherous habitats, usually
marshland, by night. Many legends have been created around this phenomenon, which has been
beautifully described by Milton in Paradise Lost:
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2. Observation of will-o’-the-wisp
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rsta.royalsocietypublishing.org Phil. Trans. R. Soc. A 372: 20140206
life cannot, have challenged conventional biological and biochemical explanations for their
existence which it is now realized is fundamentally associated with their unique ability to
create a suite of chemicals designed to protect them from the effect of high-energy radiation
insolation, temperature extremes, desiccation, barometric pressure, high metal toxicity and
high salt concentrations [1,2]. The recognition of extremophilic survival strategies and their
presence in geological microniches is critically dependent upon the adoption of analytical
chemical techniques that can indicate the presence of key biomolecular signatures [3,4],
usually demonstrated by the presence of an inorganic mineral host matrix that provides a
protective shelter for the colonies under study. The observation of extremophiles in their
natural habitats is usually a painstaking and sometimes difficult task and in many instances,
their presence is confirmed from the analytical data in conjunction with the visual recognition
of morphological indicators. Hence, extremophiles have often as a result been considered
as rather secretive entities for normal analytical procedures and a great deal of objective
scientific detective work is usually necessary to confirm their presence; the importance of
the study of extremophiles lies in the widening of the range of conditions under which we
would normally expect to see terrestrial life signatures—for example, the thermophilic or
thermotrophic salt-tolerant extremophiles existing at −52◦ C in Don Juan Pond, Antarctica,
to the xerophilic extremophiles found at +130◦ C near volcanic vents (black smokers) on the
ocean bed.
In recent years, the discovery of subsurface water on Mars, surface ice on Mars and Europa,
and mineral deposits on Mars which could harbour similar endolithic and halophilic life on which
has been identified on Earth such as jarosite and gypsum, have raised the question as to whether
extraterrestrial life, extinct or extant, could exist in forms similar to those of the extremophiles that
are found on Earth [5,6]. This has prompted the adoption of special missions to our neighbouring
planets and their satellites in the Solar System over the next few decades to specifically detect
surface and subsurface life signatures, the first of which is ExoMars, the European Space Agency
mission to Mars and scheduled for launch in 2018 as part of project Aurora, which will has been
designed to address the hazards of a manned human exploration mission to Mars scheduled for
2033 or thereafter [7,8].
At first sight, it may be rather challenging to attempt to draw a parallel between what is
known about the phenomenon of will-o’-the-wisp and extremophilic behaviour, but actually to
analytical scientists engaged in work on the characterization of the latter, several common features
are apparent. Both phenomena have long been unrecognized for what they are, they share an
unpredictability of discovery and also cannot be simply defined using one set of characteristic
values. In addition, extremophiles still often pass uncharacterized through masking by their host
or associated matrices. The definition of an extremophile also engenders several and varied tenets
under the blanket statement of an organism that can survive and reproduce in conditions that are
stressed or even deemed to be impossible for human occupation. As will be shown later, the
will-o’-the-wisp occurrence too is phenomenologically similar to this and especially so when it
will be appreciated that the scientific techniques that are now being developed for the successful
in-field recognition of extremophilic activity, past or present, are precisely those that could be
brought to bear on the mysterious will-o’-the-wisp phenomenon.
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‘..... a wand’ring fire
3
Compact of unctuous vapour, which the night
Which oft, they say, some evil spirit attends,
Hovering and blazing with delusive light,
Misleads th’amaz’d night-wanderer from his way,
To bogs and mires, and oft through pond or pool,
There swallow’d up and lost, from succour far . . . ’
The sense of mystery of the will-o’-the-wisp as a harbinger of bad news and death in the above
poem is reinforced by some of its alternative names in the literature of many countries, including
ignis fatuus, corpse-candle, irrlichtern, foxfire, fairy lights, Hob’s lantern, feu follet and elf-fire. Was
this apparition a figment of the imagination of weary and lonely travellers in desolate places
(stressed environments!) or does it have some scientific explanation? The first recorded mention
of a will-o’-the-wisp sighting appeared in 1340 when Dafydd ap Gwilym (translated by W. Sykes)
noted
‘There was in every hollow a hundred wrymouthed wisps’
and he referred to the phenomenon in Welsh as canwyll corff, literally corpse-candle, so formulating
the mysterious association between the wisps and burial places. In the English language, William
Fulke first reported the wisp phenomenon, which he termed ignis fatuus, as ‘foolish fire that
hurteth not’ in his Book of Meteors published in 1563, closely followed by William Shakespeare’s
mention of ignis fatuus in Act III of his play Henry IV Part I, published in 1608.
Since the first scientific report of the will-o’-the-wisp as ‘ignis fatuus-vapours shining without
heat’ in a text on optics by Isaac Newton in 1704 [9], which led to some intense scientific debate
through the eighteenth and nineteenth centuries, the mystery still remains unexplained.
There is much conjecture and little hard evidence to appreciate and evaluate [10]; the only
certainty is that no modern experimental analysis has been carried out on this phenomenon.
A distillation of eye witness accounts by observers and scientists [11] over the past 300 years
yields the following information about the will-o’-the-wisp phenomenon
— small, dancing flames observed in marshland, often in close association with standing
water and reeds;
— bluish luminosity, with a yellow centre, which is not sufficient to illuminate the ground;
— the flames persist for up to 15 min in the same place, often located six feet (2 m) above the
ground;
— the flames are cool to the touch and are up to six inches (15 cm) tall and one-and-a-half
inches (4 cm) in diameter;
— multiple occurrences were reported;
— the flames are susceptible to air currents and could be readily extinguished.
Although the phenomenon has been variously attributed to the spontaneous combustion of
marsh gas, or to bioluminescence and chemiluminescence processes, it is clear that on closer
inspection none of these actually describe fully the eye witness accounts of the will-o’-the-wisp
phenomenon.
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Kindled through agitation to a flame,
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Condenses, and the cold environs round
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3. Preliminary analysis
Chemiluminescence: defined as chemical reactions which are accompanied by the emission of light
at ambient temperatures but without the emanation of heat. Several observers were fortunate
to observe the bluish, dancing lights at close range for up to 2 min or more on each occasion and
remarked on the coolness of the flame; a brass-ferruled walking stick held in a flame which burned
steadily for 15 min, completely odourless and smoke-free, was cold to the touch afterwards.
Combustion: many accounts refer to the will-o’-the-wisp as a flame, but it is clearly not an ordinary
combustion flame. In only one case recorded does the observer report the successful ignition
of combustible material from a will-o’-the-wisp. Blesson [14] noted that bubbles appeared from
a ferruginous swamp in Gorbitz during the day and at night blue flames were observed at the
surface. It was conjectured that these flames could well have been present during the day but that
only at the onset of twilight did they become visible. Close approach of the observer invariably
resulted in the disturbance of the air near the flames, and on one occasion he was able to first singe
and then ignite a piece of paper in the flame. From several hundred reported sightings, this is the
only documented case of a will-o’-the-wisp causing the ignition of material and the assignment of
this particular observation to a will-o’-the-wisp occurrence must surely therefore be questionable.
4. Some possible explanations
It is without doubt that the will-o’-the-wisp phenomenon was manifestly real and widely observed
throughout Europe and North America, at least through the nineteenth century. It was associated
with stagnant water in marshy terrain and was seen on dark, warm nights; its flames seemed
to have little or no definition of boundary and were variously described as luminous yellow at
the centre with a blue colour at their edges. The flames were not hot enough to produce any
perception of warmth, much less resulting in the ignition of combustible materials, with the
sole exception of the listed observation [14] noted above. The phenomenon has been reported
as occurring near the ground surface water and up to several feet above it and was of sufficient
intensity to illuminate the neighbouring vegetation. It is possible that multiple occurrences could
have given rise to the idea of ‘dancing flames’.
Although often misattributed historically to some other luminous phenomena, it can be
concluded that the will-o’-the-wisp occurrence is definitely not the same as one of the following
natural sightings:
St. Elmo’s fire: a coronal electrical discharge from conductors and termini of objects in strong
electrostatic fields in the vicinity of an electric storm;
Ball lightning: a metastable luminous globular lightning discharge [15] generated by forked
lightning striking near the ground;
Natural gas: an evolution of ‘firedamp’ or methane in the vicinity of geological faults;
.........................................................
Bioluminescence: as exemplified by the glow-worm and the firefly, which have both been
incorrectly attributed to the will-o’-the- wisp phenomenon. It has been pointed out as long ago
as 1830 [12] that from as close as two metres, personal observation of these lights indicated that
there was no flying or suspended insect involved. Biologically, it has been recognized for some
time that only the female glow-worm glows brightly but does not fly and that the male Lampyris
noctiluca flies but is not luminescent [13]; the comments of Derham in the Philosophical Transactions
of the Royal Society issue of January 1729, are a 14-page compilation of his detailed observations
of ignis fatuus over a period of 50 years and represent perhaps the first serious but unsuccessful
attempt to explain the mystery scientifically, in which he rejected the idea of flying insects and
preferred the idea of a self-igniting gaseous emanation.
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Let us consider some possibilities
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However, the major problem in attempting to provide a rational explanation of the will-o’-thewisp phenomenon is its contemporary scarcity. There are no reports at all of modern sightings
and it is intriguing to speculate on the reason for this. Given that modern travel has opened
up many hitherto inaccessible regions to many more putative observers, coupled with a wide
public interest in natural and unexplained phenomena through the influence of the media, this is
a very surprising conclusion. The very discovery of extremophilic biology in the least expected of
places on the terrestrial surface and subsurface is witness to the increased observational scientific
prowess that is being brought to bear on natural phenomena.
More recently, Mills [17] has tried to revive interest in the will-o’-the-wisp topic with an appeal
for modern scientific analysis to be applied to the study of the phenomenon. He has undertaken
an elegant analysis of the observed sightings and has tried to correlate these with known
natural chemical phenomena such as the self-ignition of impure phosphines and methylated
phosphines, perhaps arising from a source of bacterially decomposing protein buried in a wet
depositional environment. All apparently reasonable explanations, however, have foundered,
and like extremophilic activity initially, will-o’-the-wisp must remain a mysterious biological and
biochemical phenomenon. Unlike the case of extremophiles, however, where increasing numbers
of scenarios are being discovered and reported every year and their diverse biochemical survival
strategies enumerated, the major problem facing chemical analysts who would be interested in
contributing to a scientific explanation for what must surely be one of the longest unexplained
historical natural mysteries is the total disappearance of the will-o’-the-wisp phenomenon in
contemporary times.
Perhaps the most acceptable current explanation under these circumstances which can be
proposed for the will-o’-the-wisp lights is the generation of pockets of marsh gas, which comprises
approximately two-thirds methane and one-third carbon dioxide, resulting from the bacterial
(extremophilic?) anaerobic decomposition of cellulose and proteins in vegetation; methane is
lighter than air and burns with a clear blue flame with a distinct yellow luminosity and marsh
gas bubbles can be ignited in nature above stagnant pools of rotting vegetable matter, where
indeed they are observed to burn with a blue flame, even albeit rather briefly. Tenable though
this hypothesis may be superficially, however, a major problem relates to the natural process of
spontaneous ignition of the marsh gas.
The spontaneous ignition of hydrocarbons produced from decomposition processes in
nature has hitherto been ascribed to phosphine [18–20], first reported in 1789 by Lavoiser as
phosphoretted hydrogen, whose presence in gaseous emanations is attributed to the putrefaction
of phosphatic organic matter. The reduction of phosphate to phosphine under bacterial growth
conditions has been challenged thermodynamically [21]; even more significant, however, is the
evidence that the well-known flammability of phosphine (PH3 ) is believed to be due to traces
of a higher hydride of phosphorus such as diphosphine, P2 H4 , or the spontaneously flammable
methylphosphines and it appears that pure phosphine itself is stable in air.
To combat this apparent impasse, several theories to explain the self-ignition of marsh gas from
biodegradative processes have been proposed [10], including an unspecified chemiluminescent
oxidation of volatiles and organometallic compounds entrained in the methane.
Whatever the true explanation of the will-o’-the-wisp phenomenon, perhaps the most significant
and challenging statement is its apparent disappearance from contemporary observation. There
have been very few recorded sightings even in the past century, despite the significant increase
in tourism and travel to isolated regions alluded to earlier. Could it be that the reason for the
disappearance of this haunting phenomenon can be traced to the removal of the environmental
habitats in which it once survived; the draining of large areas of swampland as the habitation
of rural areas extended outwards from industrialized centres, which incidentally has already
5
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Luminous owls: also known as ‘fox-fire’. The contamination of the plumage of roosting birds with
fungal metabolites which glow in the dark, and for which the nocturnal activities of hunting owls
has provided several reported sightings [16], cannot be confused with the essentially static and
localized dancing flames of the will-o’-the-wisp.
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manner until it is reported again—and that challenge is yet to be met.
Or is there somewhere isolated, where at the dead of night the little blue and yellow flames
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now being developed is ready and the first 21st Century sightings of will-o’-the-wisp are now
eagerly awaited . . . but what has happened to the will-o’-the-wisp in the interim?
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