en the Light emitted from various Bodies. 171 



SECTION III. 



Some Bodies' or Substances have a Power of extinguishing spon- 

 taneous Light, when it is applied to them. 



EXPERIMENTS. 



The luminous matter proceeding from the herring and the mac- 

 kerel, was quickly extinguished when mixed with the following 

 substances : 1. Water alone. 2. Water impregnated with quick- 

 lime. 3. Water impregnated with carbonic acid gas. 4. Water 

 impregnated with hepatic gas. 5. Fermented liquors. 6. Ardent 

 spirits. 7. Mineral acids, both in a concentrated and diluted 

 state. 8. Vegetable acids. 9. Fixed and volatile alkalis, when 

 dissolved in water. 10. Neutral salts: viz. saturated solutions of 

 Epsom salt, of common salt, and of sal ammoniac. 1 1 . Infusions 

 of chamomile flowers, of long pepper, and of camphor, made 

 with boiling-hot water, but not used till quite cool. 12. Pure 

 honey, if used alone. 



SECTION IV. 



Other Bodies or Substances have a Power of preserving sponta- 

 neous Light for some Time, when it is applied to them . 



EXPERIMENTS. 



Exper. 1. Some luminous matter scraped from the herring, 

 was mixed with a solution of two drams of Epsom salt in 

 two ounces of cold pump water : after shaking very well for 

 some time the phial which contained them, the whole liquid 

 became richly impregnated with light, and continued shining 

 above twenty-four hours. This experiment was frequently re- 

 peated, and with the same effect. 



Z2 



