420 Dr. Hulme’s Experiments and Observations 
§ vii. 
The Effects of nitrous Gas* on spontaneous Light . 
EXPERIMENTS. 
Exper. i. A piece of fresh herring was introduced above 
water, into this gas, at 3 P. M. and remained there four nights* 
without emitting any light: it was then withdrawn, and ex- 
posed to common air, for the space of three nights ; but did not 
become lucid, 
Exper. 2. The same experiment was made with a piece of 
herring beginning to be luminous ; but its light was gradually 
extinguished : it was detained in the gas for three nights, and 
taken out dark. It was then exposed to the open air, for the 
three subsequent nights; but its shining appearance did not 
return. 
Exper. 3. A cork with luminous matter, introduced above 
water, into this species of gas, had its light, in general, ex- 
tinguished in from 10 to 30 minutes; and, when taken into 
common air, its light very seldom re-appeared. 
Exper. 4. Fragments of shining wood, above water, in 
nitrous gas, were likewise commonly rendered dark in a very 
short space of time, as in three or four minutes ; sometimes a 
fragment, if uncommonly luminous, would not be extinguished 
in less than six or eight minutes ; and very seldom would the 
light revive, on exposing the wood to atmospherical air. 
Exper. 5. A dead shining glow-worm being put above 
water, into this gas, its light was quickly extinguished; but, 
after the insect was taken into the common atmosphere, the 
* This gas was obtained from copper and diluted nitrous acid. 
