PHOSPHOEESCENT SEA. 97 



by no means entirely, due to myriads of minute globular creatures, called Noctiluca, Captain 

 King-man reported having traversed a zone twenty-three miles in length, and so filled with 

 phosphorescent matter that during the night it presented the appearance of a vast field of 

 snow. "There was scarcely a cloud in the heavens," he tells us; "yet the sky for about 10 

 above the horizon appeared as black as if a storm were raging; stars of the first magnitude 

 shone with a feeble light, and the ' milky way ' of the heavens was almost entirely eclipsed 

 by that through which we were sailing." Several varieties of molluscs and acalephes 

 shine by their own light, while phosphorescence is often due to the decomposition of animal 

 matter. 



A French author thus describes the effect produced by the molluscs known to scientists 



PHOSPHORESCENCE OX THE SURFACE OF THE SEA. 



as Pyrosoma, on a voyage to the Isle of France. He says : " The wind was blowing with 

 great violence, the night was dark, and the vessel was making rapid way, when what appeared 

 to be a vast sheet of phosphorus presented itself, floating on the waves, and occupying a 

 great space ahead of the ship. The vessel having passed through this fiery mass, it was 

 discovered that the light was occasioned by organised bodies swimming about in the sea at 

 various depths around the ship. Those which were deepest in the water looked like red-hot 

 balls, while those on the surface resembled cylinders of red-hot iron. Some of the latter were 

 caught; they were found to vary in size from three to seven inches. All the exterior of 

 the creatures bristled with long thick tubercles, shining like so many diamonds, and these 

 seemed to be the principal seats of their luminosity. Inside also there appeared to be a mul- 

 titude of oblong narrow glands, exhibiting a high degree of phosphoric power. The colour 

 of these animals when in repose is an opal yellow, mixed with green ; but on the slightest 

 movement the animal exhibits a spontaneous contractile power, and assumes a luminous 

 brilliancy, passing through various shades of deep-red, orange-green, and azure-blue." A 

 ship plunging through these phosphorescent fields seems to advance through a sheet of 

 white flame, a field of luminous silver, scattering a spray of sparks in all directions. 

 133 



