36 PHOSPHORIC MATTER. 



although in high latitudes it is occasionally 

 visible, more especially during the warm months 

 of the year. The cause of it has excited much spe- 

 culation among naturalists ; and although many 

 of the marine molluscous and crustaceous ani- 

 mals, such as salpa, pyroso7na, cancer, several 

 medusce have been found to occasion it, yet no 

 doubt debris, from dead animal matter, with 

 which sea water is usually loaded, is also often 

 one of the exciting causes. 



As the ship sails with a strong breeze through 

 a luminous sea on a dark night, the effect pro- 

 duced is then seen to the greatest advantage. 

 The wake of the vessel is one broad sheet of 

 phosphoric matter, so brilliant as to cast a dull, 

 pale light over the after-part of the ship ; the 

 foaming surges, as they gracefully curl on each 

 side of the vessel's prow, are similar to rolling- 

 masses of liquid phosphorus ; whilst in the dis- 

 tance, even to the horizon, it seems an ocean of 

 fire, and the distant waves breaking, give out a 

 light of an inconceivable beauty and brilliancy : 

 in the combination, the effect produces sensa- 

 tions of wonder and awe, and causes a reflection 

 to arise on the reason of its appearance, as to which 

 as yet no correct judgment has been formed, the 

 whole being overwhelmed with mere hypothesis. 



Sometimes the luminosity is very visible with- 



