190 JURA. LUMINOUS ANIMALS. 



days of Pliny, and has at different times been a subject of 

 much discussion. Being too remarkable to have escaped 

 the notice of even the most common observers, and too 

 difficult of explanation not to have excited the ingenuity 

 of philosophers, different theories of the cause have 

 accordingly been proposed. Among mariners, it has, 

 like all the less common phenomena of the elements, 

 given rise to unfounded prognostics relating to atmo- 

 spheric changes ; while, like those which excite surprise 

 from their rarity, or admiration from their singularity and 

 splendour, it has been occasionally ranked among the 

 recondite and inexplicable appearances of Nature. For 

 this reason perhaps the investigation of its true origin 

 has been neglected. Mariners and fishermen have always 

 considered it as a property attached to sea water, and to 

 that under particular circumstances of approaching change. 

 Had their attention been directed to its real cause, we 

 should long ere this have been acquainted with many 

 more of the animals in which it principally resides ; and 

 have been enabled to extend the scanty list here given, 

 to an indefinitely greater number ; perhaps to all the 

 inhabitants of the ocean. It is equally to be regretted 

 that naturalists also have too generally taken it for granted 

 that the property of yielding light was attached to the 

 water of the sea itself; and that, instead of examining 

 into its real seat, they have been content to speculate on 

 its cause. Thus it has by one class been attributed to 

 the putrefaction of sea water, although the slightest ac- 

 quaintance with this element will show that, except in 

 a few rare cases described by navigators, the waters of the 

 sea do not exhibit appearances of putrefaction. On the 

 contrary, provision seems to have been made, in the sea 

 as in the air, for the speedy decomposition and dissipation 

 of all dead animal matter ; and for the incessant renewal 

 in it of an uniform purity, similar to that which the winds, 

 and other causes, effect in the atmosphere. Others have 

 supposed this light to be phosphoric; a term to which no 



