264 History of Luminescence 



glutinous matter whereof it consisteth: in which regard the cold of the 

 night beats it back again when it striveth to ascend, through which 

 strife and tossing it is fired, (for in this encounter it suffereth an Anti- 

 peristasis) and being fired it goeth to and fro according to the motion 

 of the Aire in the silent night by gentle gales, not going alwayes directly 

 upon one point, . , . 



These kindes of lights are often seen in Fennes and Moores, because 

 there is alwayes great store of unctuous matter fit for such purposes; 

 as also where bloudie battells have been fought; and in church-yards or 

 places of common buriall, because the carcases have both fatted and 

 fitted the place for such kinde of oyly Exhalations. Wherefore the 

 much terrified, ignorant, and superstitious people may see their own 

 errours in that they have deemed these lights to be walking spirits; or 

 (as the silly ones amongst the Papists beleeve) they can be nothing else 

 but the souls of such as go to Purgatorie, and the like. In all which they 

 are much deluded: For souls departed (Eccles. 9.5, 6.) cannot appeare 

 again: . . . 



There can be no doubt of the religious affiliation of the author. 



Not all the explanations relied on an exhalation set on fire by 

 antiperistasis. Christopher Merret (1614-1695) , curator of Wm. 

 Harvey's library and museum, published a museum catalogue in 

 1660 in which (under " Meteora ") he defined " Ignis fatuus, the 

 Walking Fire or Jack of the Lantern " as " a white and glutinous 

 substance seen in many places which our people call ' star fain '; 

 they believe it owes its origin to a falling star and is its stuff. But to 

 the Royal Society I openly demonstrated that it merely arises from 

 the intestine of frogs '° piled up in one place by crows." 



Willoughby and Ray,^^ according to Dr. Derham ^^ (1657-1735), 

 both thought the phenomenon was due to " shining insects." Wm. 

 Derham himself, however, who saw an ignis fatuus on a calm dark 

 night, wrote: " with gentle Approaches I got up by Degrees within 

 two or three yards of it . . . found it frisking about a dead Thistle 

 growing in the Field, until a small motion of the Air . . . made it 

 skip to another Place, and thence to another, and another." Derham 

 related that he saw this fifty-five years ago but " I am of the same 

 Opinion now, that it was a fired Vapour," not glowworms, as he 

 never saw glowworms in such large numbers. 



="> According to J. L. Wolff (1733), Robert Fludd (1574-1637), is alleged to have 

 caught an ignis fatuus and found in his hand a sticky matter similar to the sperm 

 of frogs. 



^^J. Ray made the suggestion that an ignis fatuus was "nothing else than swarms 

 of these flying glow-worms," in his Travels through the Low Countries, etc. (1673) . 

 during a stay near Bologna in 1664. 



" W. Derham in Phil. Trans. 36: 204-214, 1729. See Priestley (1772. 580 ff.) for other 

 records of ignis fatuus. 



