64. METEOROLOGICAL 
is well known that one of the gaseous compounds 
of phosphorus and hydrogen takes fire as soon 
as it comes in contact with atmospheric air; and 
it is supposed that in certain circumstances the 
putrefaction of animal, matters, contaiming phos- 
phorus and sulphur, besides the four elements 
carbon, hydrogen, nitrogen, oxygen, and phos- 
phate of lme, is accompanied by a production of 
this phosphuretted hydrogen gas.  Will-o’-the- 
Wisp is observed in bogey 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 flickers 
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 
ihe production of phosphuretted hydrogen with evo- 
lution of hght 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 
jatwus, depended upon the production and spon- 
