22 EYE SPY 
with animal life, which, though dwelling in depths 
scarce reached by the faintest gleam from the sun, 
swim about enveloped in their self-illumined halo. 
While all these phenomena come under the 
general term of phosphorescence, the inference of 
the presence of phosphorus is incorrect; many 
substances without a trace of phosphorus in their 
constitution emit light with equal brilliancy. 
The well-known commercial article called " lu- 
minous paint " is an apt example, which, while 
containing no trace of phosphorus, glows like fox- 
fire at night, especially after having been exposed 
to the sun's rays during the day, giving forth in 
the dark hours the light which it has thus ab- 
sorbed, and being thus of utility in its application 
to clock faces and match-boxes. 
Calcined lime and burnt oyster-shells, in com- 
bination with certain acids, become luminous at 
night by the similar power of absorption and 
transmission of light vibration which is supposed 
to be the secret of much of the so-called phos- 
phorescence. 
But fox-fire is believed to be of a different 
nature, more chemical in its character, and usu- 
ally emanates from a fungus, either visible in the 
form of mould or toadstool, or existing as an al- 
most invisible essence which saturates the decaying 
wood, a species known as Thelaphora cerulea being 
credited with most of the luminous manifestations. 
