The pleasing phenomenon known as the phosphorescence of the sea is generally, though by no means entirely, due to myriads of minute globular creatures, called _Noctiluca_. Captain Kingman 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. [Illustration: PHOSPHORESCENCE ON THE SURFACE OF THE SEA.] A French author thus describes the effect produced by the molluscs known to scientists 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 multitude 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. CHAPTER IX. DAVY JONES’S LOCKER.—SUBMARINE CABLES.