OBSERVATIONS ON SPONTANEOUS LIGHT. 101 



itopple. It continued to fhine pretty vividly for fome little 

 time ; then the light gradually diminifhed, fo that at twelve, 

 only a fmall fpark remained. 



Exp. 5. At 10 P. M. another cork, illuminated with mac- 

 kerel-light, was introduced above water, into 24- ounces of 

 the gas ; and its light was nearly extinct at twelve. 



Exp. 6. At 8 P. M. a fragment of fhiniug wood was put 

 above water, into 24 ounces of the gas ; and it had not been 

 long there before the light difappeared. It was then taken 

 out, and expofed to the action of atmofpheric air, when its 

 Alining property foon returned. 



Exp. 7. Another fragment of brightly mining wood was in- 

 troduced above water, into the fame quantity of the gas, at 

 10 P. M. and the light was extinguifhed in the fpace of an 

 hour. After this, it was expofed to the open air, and the 

 light gradually revived. 



Exp. 8. At 8 P. M. a luminous dead glow-worm was put 

 above water into the gas ; its glowing appearance gradually 

 faded, and in a fhort time became quite invifible. It was 

 then taken out, and the light, by degrees, re-appeared as 

 vivid as before, 



OBSERVATION. 



This gas, we find, has alfo an extinguifliing property, with 

 refpect to fpontaneous light : but, in general, the light returns, 

 if the object of experiment be taken out, and expofed to the 

 open air. 



§ S 



The Effects of fulphu rated hidrogen Gas * on fpontaneous Light ', 



EXPERIMENTS. 



Exp. 1. At noon, apiece of a very frefli mackerel, with Sulphurated hi- 

 a bright eye, was introduced above water, into 24- ounces dr0 &f n e * tm - 

 of this gas, and was retained therein for three fucceflive neous light more 

 evenings, without emitting any light. It was then expofed to effeftua!] y anc * 

 atmofpheric air ; yet it continued dark on the two following hentfrtban 



car- 

 bonic acid. 



* This gas was obtained from fulphuret of potafh and diluted 

 muriatic acid. 



nights ; 



