on the Light emitted from various Bodies . 
409 
OBSERVATION. 
It appears, from these experiments, that oxygen gas does not 
act upon this kind of light, so as to render it much more vivid 
than it is in atmospherical air ; which is quite contrary to what 
some authors have alleged. 
§ in- 
The Effects of azotic Gas on spontaneous Light . 
1 . Azotic Gas, obtained from lean muscular Flesh and diluted 
nitric Acid, in a very low Heat, as recommended by M. de 
Fourcroy. 
EXPERIMENTS. 
Exper. 1. A piece of fresh mackerel, weighing about three 
drams, was introduced above water, into about eight ounces of 
this azotic gas ; and it was retained therein five days, without 
emitting any light. 
Exper. 2. About the same quantity of fresh herring was then 
put above water, into the same gas used for the last experiment, 
and .remained in it for the space of three days, in a dark state. 
This experiment was repeated, and with a similar result. 
Exper. 3. At 45 minutes past 7 P. M. a cork, finely illuminated 
with mackerel-light, was put above water into the gas, and it 
was found pretty luminous at eleven. On the next evening, at 
eight o’clock, it still exhibited a faint degree of light. 
A similar experiment was made, at the same time, in atmo- 
spherical air. At 11 P. M. the cork was but moderately lumi- 
nous ; and on the next evening it was dark. 
MDCCCI. 3 G 
