13 



derived from decaying organic matter'? Imagine a bubble or 

 stream of bubbles of phosphoretted hydrogen rising to the surface of 

 the swamp and igniting spontaneously on coming into contact with 

 the air. Surely they would be observed as sudden flashes or a 

 stream of flashes at one spot, with similar flashes visible all around. 

 There would be no hovering or flitting about in regard to them. 



There is, however, another theoretical cause not mentioned in 

 the Oxford Dictionarii, and so far as I am aware not generally 

 considered nowadays, though as we shall see later very generally 

 accepted a century or so ago, and that is that the appearance is due 

 to a light-giving insect hovering or flitting about. Such an 

 explanation would, I think, be most obvious and probable were it 

 not for the difficulty of accounting for the luminous insect. 

 Attempts have been made to surmount this difficulty in various 

 ways. Some naturalists have thought that the luminous insect 

 must be the glow-worm {Laviiiyris nortibica), but the reasons against 

 this are overwhelming. The glow-worm is, ofcourse,theonlyinsectin 

 this country that is normally luminous, but only the male glow-worm is 

 endowed with wings and capable of ' hovering and flitting' about, and 

 any light emitted by him is for the present purpose so minute as to 

 be negligible. Then there is the possibility that it may be ' the 

 male glow-worm bearing on amorous wing his joyous partner,' as one 

 worthy has it," but this would, I am afraid, be far beyond the wing 

 power of the male glow-worm. 



The belief that the Will-o'-the-Wisp is caused by some flying 

 insect apparently dates back at least to the time of Bacon who calls 

 it the Fbfinti-Glnironn : — " The nature of the Gloivoni is hitherto not 

 well observed. Thus much we see, that they breed chiefly in the 

 hottest months of Sunniwr : and that they breed not in Champaign, 

 but in Bushes and Hedges. Whereby it may be conceived, that the 

 Spirit of them is very fine, and not so to be refined, but by Summer 

 heats. And again, that by reason of the fineness, it doth easily 

 exhale. In Italy, and the Hotter Countreys, there is a flie they 

 call Lncciole, that shineth as the Gloworm doth, and it may be is 

 the Fli/ing-GloHonii ; but that flie is chiefly upon tens and Marshes, 

 But yet the two former observations hold, for they are not seen 

 but in the heat of Summer ; and Sedge and other green of the Fens 

 give as good shade as Bushes. It may be the Gloivorms of the Cold 

 Countreys ripen not so far as to be winged." {Xat. Hist., Cent. 



VIII., Exp. 712, p. 149.) ' 



* Annals of Nat. Hist., New Series, vol. i., 1837, p. 551. 



