Eudiometer truly pioneered by Count Alessandro Volta (1745–1827), an Italian physicist who is well known for his contributions to the electric battery and electricity. Aside from its laboratory function, the eudiometer is also known for its part in the "Volta pistol". Volta invented this instrument in 1777 for the purpose of testing the "goodness" of air, analyzing the flammability of gases, or to demonstrate the chemical effects of electricity. Volta's Pistol had a long glass tube that was closed at the top, like a eudiometer. Two electrodes were fed through the tube and produced a spark gap inside the tube. Volta's
Will-o'-the-wisp create ephemeral fires. Furthermore, phosphine produces phosphorus pentoxide as a by-product, which forms phosphoric acid upon contact with water vapor, which can explain "viscous moisture" sometimes described as accompanying ignis fatuus. 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). Early critics of the marsh gas hypothesis