- 
too Observations upon Luminous Animals. 
Experiment 4.—The luminous substance of a glow-warm , 
was exposed to a degree of heat which would have been. 
sufficient to inflame phosphorus, without increasing the ° 
brilliancy of its light; and further, it could not be made to 
burn by bemg applied to a red hot iron, or to the flame of 
a candle. i ‘ 
Experiment 5.—A delicate thermometer was introduced 
amongst some living glow-worms, during the time they 
gave out much light: the temperature of the room being 
69, the instrument rose to 75, 76, and 77, according to” 
circumstances, as the warmth was reflected. from the hand, ° 
or dissipated by the worm crawling over cold ‘substances. 
The luminous portion of the tail, when very brilliant, ap- 
peared to raise the thermometer more quickly than the other 
parts of the body, but it was not invariably the case. When 
shining strongly, I thought that the duminous rings com- 
municated the sensation of warmth to the hand; but this 
was probably a deception, as the actual degree of heat was. 
not sufficient for such an effect. It should however be. 
mentioned, that in Templar’s observations on the glow- 
worm, he said his feelings deceived him, if he did notex- 
perience some heat from the shining of the inseet*: 
Experiment 6.—TYo satisfy myseif how far the evolution 
of heat during the shining of glow. worms depended upon 
the lite of the animals, | cut off the luminous portion of 
the tail from several living worms, and T found that if the 
thermometer was applied to “them ren it was 
raised by them. one or two degrees ; but after these parts 
were dead, althoneh they continued to emit light, they pro- 
duced no effect whatever upon the tnstrament. "> 
Experiment 7.—Some hemispherical meduse were put 
-intoa Spoon containing a small quantity of sea water, and 
held over a burning candle. As soon as the water became 
- heated the meduse appeared like illuminated wheels, the 
Spots at the margin and centre alone emitting light; in” 
which manner they’ shone vividly and permanently for 
about 20 seconds, when they shrunk and died, after which 
they were no longer luminous. 
Experiment 8.—Some of the same species were put into 
spirits: a strong and unremitting light was instantly given 
out, which issued from the central and marginal parts, as 
in the preceding experiment, and continued until (hey died. 
Experiment 9.—Some of the scintillating and hemispheri- 
cal species of medusa, contained in a small glass jar, were 
#* Fhil ‘Trans. No, 72, 
introduced 
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