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 book "," by Ludwig Lavater, in the chapter titled "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. In 1776, Alessandro Volta first proposed that natural electrical phenomena (like lightning) interacting with methane marsh gas may be the cause of ignis fatuus. 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).