226 COMBUSTION OF LIME. 



COEALLINE LIGHT. 



The common Coralline, if held to the flame of a 

 candle, burns with a most vivid white light. If we 

 take a shoot and let it dry, and then present the tips 

 to the flame, just at the very edge, not putting them 

 into the fire, the ends of the shoot will become red 

 first, snapping and flying ofi" with a crackling noise ; 

 some, however, will retain their integrity, and these 

 will presently become white-hot, and glow with an 

 intensity of light most beautiful and dazzling, as long 

 as they remain at the very edge of the flame, for the 

 least removal of the Coralline, either by pulling it away, 

 or by pushing it in, destroys the whiteness.. It will 

 however return when again brought to the edge. The 

 same tips will display the phenomenon as often as you 

 please. I did not find the incrusting lamina that 

 spreads over the rock before the shoots rise, show the 

 light so well as the shoots. 



The brilliant light obtained by directing a stream 

 of oxygen gas upon a piece of lime in a state of com- 

 bustion, occurred to my mind as a parallel fact ; and 

 I experimented with other forms of the same substance. 

 The polypidoms of Cellularia avicularia, and of 

 Eucratea chelata, one of the stony plates of Canjophyl- 

 lia, and a fragment of oyster-shell, I successively placed 

 in the flame, and all gave out the dazzling white light 

 exactly as the Coralline had done. The homy poly- 

 pidom of a Sertularia, on the other hand, shrivelled 

 to a cinder. 



