]02 OBSERVATIONS ON SPONTANEOUS LIGHT. 



nights : but, on the third, it was very luminous, and remained 

 fo on the fourth and fifth. 



Exp. 2. The fame experiment was then made with a piece 

 of frefh herring, which was alfo kept in the above gas, for 

 about three nights, without being luminous. After expofure 

 to common air, it did not emit any light during the firft 24 

 hours. However, on the fubfequent night, it began to fhine, 

 had a very bright light on the following evening, and conti- 

 nued (hining for feveral fucceeding nights. 



Exp. 3. A cork, fmeared with the luminous matter of a 

 herring, was put above water, into 2 4 ounces of the gas ; and 

 the light was extinguiflied in lefs than an hour. The experi- 

 ment was repeated in the fame gas, and with the fame refult. 



Exp. 4. A cork, illuminated with mackerel light, was in- 

 troduced into the fame quantity of gas ; and was dark in half 

 an hour. 



Exp. 5. A fragment of fhining wood, being put into the 

 gas, became dark in eight minutes. A fecond piece became 

 dark in five minutes. They were then taken out, and conti- 

 nued dark all that evening. On the next evening, one of the 

 pieces was uncommonly lucid. 



Exp. 6. At 10 P. M. another fragment of brightly fhining 

 wood was introduced above water, into 24 ounces of the gas, 

 and was extinct at eleven. It was then expofed to the open 

 air ; but there was no return of light that evening. On the 

 following night, it was found pretty luminous. 



Exp. 7. A finely Alining dead glow-worm was next put 

 above water, into this gas, and its light was quickly extin- 

 guifhed. In a fecond experiment, in the fame gas, the light 

 was much flower in its extinction. In both inftances, after 

 the infect was withdrawn, and placed in atmofpheric air, the 

 light gradually revived. 



OBSERVATION. 



It is apparent, by thefe experiments, that fulphurated 

 iiidrogen gas extinguifhes fpontaneous light much fooner 

 than carbonic acid gas, and that, in general, the light returns 

 much more flowly, when the fubject is expofed to atmofpheric 



§ 7. 



