A curious instance of this occurred to Monsieur Peron, in his voyage from Europe to the Isle of France. Between three and four degrees north latitude, during the obscurity of a night intensely dark, the wind blowing a hurricane, and the vessel making a rapid progress, he was struck by the sudden appearance of a vast sheet of phosphoric fire, floating before the ship, and covering a considerable space. The vessel presently made its way through this inflamed part of the sea, which enabled the observant navigator to discover that this prodigious light was occasioned entirely by an immense number of small animalcules, which swam at different depths, and appeared to assume various forms. Those which were most immersed in the water, looked like great red-hot cannon balls: whilst those on the surface resembled cylinders of red-hot iron. Some of them were soon caught, and found to vary in size, from three to seven inches. All the outside surface of the animal was bristled with thick oblong tubercles, shining like so many diamonds; and these seemed to be the principal seat of its wonderful phosphorescence. The inside, also, appeared furnished with a multitude of little, narrow, oblong glands, which possessed the phosphoric virtue in a high degree.

When in a tranquil state, the colour of these brilliant inhabitants of the ocean is an opal yellow, mixed with green; but, on the slightest movement of those voluntary contractions exercised by the creature, or those which the observer can at pleasure excite by the. least irritation, the animal seems to inflame, and it becomes instantly like a piece of red-hot iron of the most vivid brilliancy. When its phosphorescency declines, it assumes a succession of light elegant tints, that are very pleasing to the eye, such as reef, aurora, orange, green, and azure blue; the last is particularly lively and pure. The organization of this animal, which is called the Pyrosoma Atlanticum, ranks it amongst the most singular of the zoophite tribe; whilst its extraordinary phosphoric powers render it the most beautiful that has yet been seen.