Another remarkable oceanic phenomenon is the brilliant phosphorescence of the water, which frequently occurs in low latitudes; and, presuming they will not be misplaced, I shall make a few observations on the subject. On my passage from England, and while we were about 2° of south latitude and 26° of west longitude, I was called up by the captain, about half-past ten o’clock at night, to witness a remarkable appearance the sea had assumed. Upon reaching the deck, one of the most magnificent scenes imaginable presented itself; all round the ship, and to as great a distance as the eye could reach, the swell, which was running pretty high, was emitting from its surface, at short intervals, long broad sheets of phosphorescent light, which continued bright only for a second or two, and then disappeared. The continued glare of these long streams of light, their sudden appearance and disappearance, as if detached portions of sheet lightning were flashing from wave to wave, gave a wild and terrific aspect to the surface of the ocean; the reflection from it was so great, that the sails of the ship were illumined by the glare. On looking over the ship’s stern, her wake for about fifty yards was one continued stream of pale yellow light, upon which, ever and anon, were floating away, and becoming extinct, curious masses of a circular shape, varying from half a foot to two feet in breadth, of a livid hue, similar to that which burning sulphur emits. These masses retained their livid flame-like appearance till they reached about six or eight yards from the ship, when they gradually became extinct; their beautiful colour contrasting singularly with the pale yellow stream on which they floated. This curious state of the sea only lasted about a quarter of an hour, the water then assuming its usual aspect, the foam at the ship’s bow only presenting the sparkling appearance which it usually exhibits within the tropics. This occurred on the 7th of July; the weather had been cloudy all day, with the thermometer 79° at noon; the night was dark, and it was blowing a fresh breeze from E.S.E., the ship going at the rate of six knots an hour.
It is well known that the circular masses of light which I have described, are produced from aggregated masses of very small marine animals, to which the name of Pyrosoma is given; I did not, however, capture any, as my towing net was at this time out of order, but during my voyage to Ceylon I was more fortunate; on the 25th of November, 1843, in about 3° and 4° N. lat., and 23° W. long., with cloudy weather, and the thermometer 81° at noon, shortly after it became dark, we got into a field of these animals, and though the brilliancy of their light was not so great as on the former occasion, they were more numerous, the ship sailing through them for several hours. They were seen in broad shoals at great but irregular distances from each other. The towing net on being thrown overboard soon procured me a large supply of the extraordinary animals of which these shoals were composed; they gave out a bright pale yellowish green light, which they retained for some time after they were brought on board. Each mass was shaped not unlike the finger of a glove, being hollow, and closed at one end; they varied a little in size, but were generally about four inches in length. The little animals of which these masses are made up, are placed horizontally, and lie closely packed over each other, their heads being towards the outer surface. When kept in a glass in salt water for some time, they soon separated from each other, and being very transparent, were then scarcely to be distinguished from the water; they taste exactly like fresh oysters. During this voyage, I obtained four distinct species, two of which were taken off the Cape of Good Hope; one of these finger-like masses, taken near the Equator, measured about two feet in length. I have often observed close to the ship these bodies at a considerable depth, giving out a faint light; and I am persuaded that the brilliant flashes which were emitted from the sides of the swell, on the first occasion, were caused by the number of the Pyrosomæ then existing in the sea. The scintillations which issued from the foam, dashed up by the ship, were caused by a phosphorescent microscopic species of shrimp (Noctiluca oceanica? Spix), which I collected in great numbers, in a net made from an old flag.
Our voyage home was a quick and a very pleasant one. We were only thirty-two days altogether at sea from Maranham, we had no rough weather, and the only calm day we experienced occurred between our losing the N.E. trades, and falling in with westerly winds. The nearer I approached home, the more my desire increased to be again among my friends; and this I believe, under similar circumstances, almost universally occurs. When we are at a great distance from, and know that we have no immediate chance of returning to, those who are dear to us, we suppress as much as possible the indulgence in hopes which cannot be realized; but when we feel that every hour is bringing us nearer home, we throw off all restraint on our imagination, and only regret that our progress cannot be accelerated. On the evening of the eighth of July the welcome cry of “land” was heard, and on the following afternoon we made the mouth of the Mersey, but for want of sufficient water, we had to stand off and on till next morning, during which interval we experienced a smart gale of wind from the N.N.W., which kept us all awake. Early next day, the 10th of July, 1841, I stood once more on British ground, after an absence of upwards of five years.
Having now brought my narrative to a conclusion, it only remains to notice that the object I had in view when I left England, was accomplished to the satisfaction of all concerned in it, and the anticipations I had indulged of the pleasures to be derived from such an expedition, have not been disappointed. If almost every day brought its little annoyances, they were more than compensated by the delight which new scenes and objects for study constantly produced. Difficulties only appear insurmountable when they are not looked boldly in the face; and it is fortunate for us that the bright side of the picture of the past presents itself more frequently than the dark. I have much to congratulate myself upon; for although often exposed both by night and by day, my health, save only on one occasion, continued good; and with very few exceptions, I received the greatest kindness from all my fellow men with whom I came in contact. I have also been more fortunate than many natural history travellers, for the numerous collections shipped to England, from time to time, all arrived safely; the letters, too, which I despatched, reached their destination, with only one exception; and not one of those from home was lost, although often long in coming to my hands. It was not without many regrets that I left Brazil, for the life I led was free and independent; the climate agreed better with my health than that of England; and the country is beautiful, and richer than any other in the world in those objects, to the study of which I have devoted my life.
THE END.
Printed by Reeve, Benham and Reeve, King-William Street, Strand.
FOOTNOTES
[1] Personal Narrative, vol. iii. p. 36.
[2] Echites atroviolacea, Stadelm., and E. crassinoda, Gardn.