The phosphorescence of the sea presents a most remarkable spectacle. Sometimes the vessel, while ploughing her way through the billows, appears to mark out a furrow of fire. Each stroke of an oar gives rise to sparks of light, sometimes tranquil and pearly, at others brilliant and dazzling. These movable lights, too, are grouped in endless varieties; their thousand luminous points, like little stars, appearing to float on the surface; and their matter forming one vast sheet of light. At such times, the bright waves heave, roll, and break in shining foam; or large sparkling bodies, resembling the forms of fishes, pursue each other, disappearing and bursting forth anew. Beautiful illuminations of the same kind are frequently seen at a great depth in the clear water, which in the night time becomes jet black. Often, through this dark, yet limpid medium, have voyagers amused themselves, by tracking the routes of large fishes, such as porpoises or sharks, gleaming along in lines of light beneath the abyss, itself invisible with gloom. As Captain Tuckey passed in his voyage towards Prince’s Island, the ship seemed to be sailing on a sea of milk. In order to discover the cause of such an appearance, a bag, having its mouth distended by a hoop, was kept overboard, and, by means of it, vast numbers of small animals were collected. Among them, were a great many small sea animals, with innumerable little creatures attached to them, to which Captain Tuckey principally attributed the whitish color of the water. [Illustration: _Luminous marine animals, magnified._] Thirteen species of cancer were observed, not above one fourth of an inch long; eight having the shape of crabs, and five that of shrimps. Among these, some luminous creatures were discernible. When one species was examined by the microscope, in candle-light, the luminous property was observed to reside in the brain, which, when the animal was at rest, resembled a most brilliant amethyst, about the size of a large pin’s head; and from this there darted, when the animal moved, flashes of a brilliant and silvery light. Of the number of these little creatures, of some of which a magnified representation is here annexed, some interesting statements are furnished by Captain Scoresby. “During a run of fifty leagues,” he says, “the sea was constantly of an olive-green color, remarkably tinted; but, on the afternoon of the 17th of April, it changed to transparent blue. This green appearance of the sea in these latitudes, was occasioned by myriads of small marine animals. A calculation of the number of these animals, in the space of two miles square, and two hundred and fifty fathoms deep, gave an amount of 23,888,000,000,000!