286 PHOSPHURETTED HYDROGEN. 



fatuus, we produce a current of air, 

 which drives the light gas forwards. 



Q. Wliy does an ignis fatuus run AFTEB us, 

 when we FLEE from it in fright ? 



A. When we run away from the 

 ignis fatuus, we produce a current in 

 the way we run, which attracts the light 

 inflammable gas in the same course. 



Q. Is not a kind of Jack o'Lantern sometimes 

 produced by an INSECT? 



A. Yes; a swarm of luminous 

 insects sometimes passes over a meadow, 

 and produces an appearance exactly like 

 that of the ignis fatuus. 



Q. May this meteoric appearance be attribu- 

 ted to any OTHER cause, besides those mentioned ? 



A. Yes; if many horses, sheep, 

 pigs, or oxen, are pastured on a 

 meadow, the animal vapour arising from 

 them (strongly electrified by the air) 

 will ignite, and produce a luminous 

 appearance. 



Q. May not many GHOST stories have risen 

 from some ignis fatuus lurking about church-yards ? 



A. Perhaps all the ghost stories 

 (which deserve any credit at all) have 



