412 Dr. Hulme's Experiments and Observations 
Exper. 17. A cork, finely illuminated with herring-light, was 
next introduced above water, into this gas, at 20 minutes past 8 
P. M. The light was much diminished at 45 minutes past 8 ; 
at 11 the cork had become almost dark. On the following 
night, a glimmer was still apparent. 
Exper. 18. Another cork, made very luminous with herring- 
light, was put above water, at 40 minutes past 7 P. M. and it 
continued pretty lucid at eleven. On the next evening, the light 
was merely visible. 
A similar experiment was made, at the same time, in atmo- 
spheric air, and with nearly the same effect. 
OBSERVATION. 
It is a remarkable circumstance, that azotic gas, which is 
incapable of supporting light from combustion, should be so 
favourable to the spontaneous light which is emitted from fishes, 
as to preserve its existence and brilliancy for some time, when 
applied upon a cork ; yet that it should prevent the flesh of the 
herring and the mackerel from becoming luminous, and also 
extinguish the light proceeding from rotten wood. 
§ iv. 
The Effects of hydrogen Gas or inflammable Air * on spontaneous 
Light. 
EXPERIMENTS. 
Exper. 1. At g P. M. a piece of fresh herring, weighing about 
three drams, was introduced above water, into hydrogen gas. 
* This gas was obtained from zinc and diluted sulphuric acid. 
