40 



No renovation 

 after a week 



Three extinc- 

 tions and reno- 

 vations of a 

 jlow-worra 



OBSERVATIONS ON SPONTANEOUS LIGHT. 



Exp. 13. A third fragment, fomewhat larger than the for- 

 mer, and equally luminous, was put above water, at the fame 

 time as the one in the laft experiment, where it was foon de- 

 prived of its light. It was retained there, in a dark ftate, from 

 the 2d of October till the 10th of November ; it was then taken 

 out, and expofed to the action of atmofpherical air, for feveral 

 days, but there was no return of light. 



Exp. 14. About 7 P. M. a mining dead glow-worm was 

 introduced above water into the gas, and its light was Toon 

 extincl. It was then expofed to the open air, where, in a 

 very fhort time, it flione as brightly as before. 



Exp. 15. Athalf an hour pail 9 P. M. the fame glow-worm 

 was again introduced above water; when its light in a fhort 

 time difappeared. It was taken out for expofure to common 

 air at 1 1, and its glowing property was immediately reflored. 

 It was again replaced in the gas, where it foon loft all its light 

 a fecond time, and was kept in that dark ftate for 24 hours ; 

 when taken out, it continued dark for a little time, and then 

 the infect gradually recovered its priftine fplendour. 



OBSERVATION. 



From thefe experiments we learn, that hidrogen gas, in 

 general, prevents the emiffion of fpontaneous light, and alfo 

 extinguifhes it when emitted ; but, at the fame time, it does 

 not hinder its quick revival, when the fubject of the experiment 

 is again expofed to the aclion of atmofpherical air ; although 

 the light may have been a confiderable time in an extinguifh- 

 ed ftate. 



(To be concluded in our next.) 



Caution 



