Today I contacted Dr. Allan Mills of the University of Leicester's
Geology Department, who has written two of the very few papers that
exist about Will-o'-the-wisps. He proved to be a most jovial and
helpful man, and it was an absolute pleasure to speak to him; I came
away from the experience rather wanting to invest more time in
researching the whole phenomenon, which I have been doing.

Dr. Mills had written a paper in 1980 in Chemistry in Britain that
described his experiments with trying to get phosphene to ignite marsh
gas. As David Clarke said, in his Peakland Spooklights article:

Using laboratory conditions he consistently failed to reproduce
a will o'the wisp type flame using methane, phosphene and other
substances suspected as contributors to the chemical soup in
marshland. What is more, he could not find any other natural
spark which could ignite gasses produced from rotting vegetable
matter. Whatever the will o'the wisp was, he concluded, it was
not a product of marsh and their gas.
- http://www.indigogroup.co.uk/edge/Peakland.htm

What was not mentioned by Clarke, and what has not been mentioned by
any of the other authors who cite Mills work (including Devereux,
Corliss as far as I know, and Beavon) is that Dr. Mills published a
subsequent paper in 2000 in the journal Weather which outlines a new
theory that, for safety reasons, Dr. Mills is unable to test.

In any case, we spoke about the history of the lights and various
other leads that I'm slowly chasing up and will be trying as much as
possible to document on my ignis fatuus page:

http://inamidst.com/lights/wisp

The main problem is that there is now an impasse. Dr. Mills is unable
to proceed with experiments to test his theory because the gases
involved are highly toxic; and field reports of Will-o'-the-wisps were
even said to have been dwindling by 1855 because of drainage. Couple
that with encroaching urbanisation and you have a considerable lack of
sightings.

Having said that, Wikipedia mentions some research by Garlaschelli and
Boschetti wherein the traditional mechanism of phosphene was said to
be proven, which is worth pursuing. I've also found some details about
a phenomenon where leaking gas was said to occur naturally from the
ground and be ignitable, manually. This proves at least that the gases
are present in such a form as to be flammable and sustain themselves.

I'd also like to compile a database of the sightings that have been
reported, and the locations at which they occur. Perhaps there are a
handful of isolated sites at which field research could still occur.
It would also be worthwhile, then, investigating the folklore as to
the effect of the weather of the appearance of the lights, so as to
pick a peak time to go looking for them. And there's also the
possibility of an international venture along these lines.

It was especially nice to have talked to someone who is not only an
expert of many years in the subject, but someone who was very open
about his research. It doesn't happen in this field often in my
experience, mainly because it is by its nature a very slow moving and
tedious underfunded beast. But I think a little attitude might go a
long way towards changing that.

Cheers,

--
Sean B. Palmer, mysterylights.com
Homepage: http://inamidst.com/sbp/