52 LUMINOSITY OF THE SEA. 



been made in order to explain it. After all, however, 

 the solutions of the problem have been based rather 

 on hypothesis, than on fixed and solid data ; facts have 

 been ascertained bearing upon the question, but too 

 much stress has often been laid upon them. It is 

 not, we conceive, to one and the same cause that the 

 luminosity of the sea is invariably to be attributed ; 

 indeed, it would positively appear, that several causes 

 alike operate to produce it, in difi"erent situations, and 

 under diflferent circumstances. To a consideration of 

 them, the attention of the reader is now directed. 



The light of the sea, as displayed during the night, 

 appears, according to the accounts of all who have wit- 

 nessed it, to be phosphorescent ; its appearance pre- 

 cisely resembles that given out by a piece of phos- 

 phorus in the dark ; it has the lurid hue of this sub- 

 stance, which every person must have remarked. Now 

 we know that this luminosity is not produced by solid 

 phosphorus alone, but that fluids containing phosphorus 

 in their composition also gleamx with a pale bright 

 lustre. There are, however, other sources of phospho- 

 rescent light, or light regarded as connected with this 

 principle. Many of the lower tribes of animals are 

 luminous. 



Among the acalephse, (sea nettles,) the medusa, and 



