64 METEOROLOGICAL 



is well known that one of the gaseous compounds 

 of phosphorus and hydrogen takes fire as soon 

 as it eomes in contact with atmospheric air ; and 

 it is supposed that in certain circumstances the 

 putrefaction of animal matters,, containing phos- 

 phorus and sulphur, besides the four elements 

 carbon, hydrogen, nitrogen, oxygen, and phos- 

 phate of lime, is accompanied by a production of 

 this phosphuretted hydrogen gas. Will-o'-the- 

 Wisp is observed in boggy lands, and where it is 

 seen some animal or perhaps an unlucky traveller 

 has been swallowed up in the mire. 



The "corpse-candle" of the Welsh, which nickers 

 over churchyards, is attributed to the above cause, 

 and the same may be said of that mysterious pro- 

 duction of light which occasionally takes place in 

 dissecting rooms. 



But no chemical experiment, made with organic 

 matters, has yet been brought forward to prove 

 the production of phosphuretted hydrogen with evo- 

 lution of light by submitting these matters to the 

 process of putrefaction. Indeed, I have shown, as 

 will be stated in a future chapter, that the phos- 

 phorescence of dead fish does not appear to depend 

 upon the presence of the chemical element phos- 

 phorus. 



If, however, it were placed beyond doubt that 

 the phenomenon of the Will-o' -the-Wisp or Ignis 

 fatuusj depended upon the production and spon- 



