The troops were decently clad, and consisted of about five hundred, principally negroes and mulattoes, officered by Europeans.
All arrangements having been completed, we left the island in the evening, with a fine north-east trade breeze.
CHAPTER II.
Enter the tropics—Flying fish—Luminosity of the ocean—Magnificent scene—Phosphoric light—Interesting facts in elucidation of that phenomenon—Albicores and Bonitos—A colossal whale—Sea birds—Gigantic species of albatross—Description of those birds—Their manner of flight.
On the 31st of May we lost the north-east trade, in 8° 40′ north, and longitude 23° west, after which we experienced variable winds with torrents of rain, until the 4th of June, when we had the south-east trade in latitude 4° 38′ north, and longitude 22° 49′ west, and crossed the equator early on the morning of the 7th, in longitude 27° 5′ west, being altogether only thirty-two days from Plymouth, including our delay at St. Jago.
On entering the tropics many animate objects excite attention, among others the flying-fish; it is surprising how many different opinions have been formed on the subject of this fish; some considering it seeks the air for sport or pastime, whilst others regard it as only taking flight when pursued, and thus decide its existence to be a continued series of troubles and persecutions. Between such opposite opinions, we can only form our judgment from actual observation, and there is one circumstance without any doubt resting upon it; that the supposed war of extermination exercised against them has not diminished their numbers, for they are observed in as large “flocks” at the present day, as navigators have related of them former days; they must also have had a long cessation of hostilities from the time of birth, to enable them to arrive at maturity. To say that these fish undergo persecution more than any other living animals of the creation, is absurd, for we may observe the same principle throughout the whole of the animated kingdom of nature.
On arriving in tropical regions, this curious fish is seen, and affords some variety to the tedium of a ship; the passengers amusing themselves by watching its flight, and sometimes its “persecution,” when pursued by bonitos, dolphins, albicores, among the finny, and tropic birds, boobies, gannets, &c. among the feathered tribe. I have frequently derived both information and amusement by watching the flight of these fish; to observe them skim the surface of the water for a great distance, sometimes before, and at other times against the direction of the wind, elevating themselves either to a short height from the surface, or to five or six feet, and then, diverging a little from their course, drop suddenly into their proper element; sometimes when their flight was not high above the water, and it blew fresh, they would meet with an elevated wave, which invariably buried them beneath it, but they would often again start from it and renew their flight.
I have never yet been able to see any percussion of the pectoral fins during flight, although such a high authority as Cuvier says, “the animal beats the air during the leap, that is, it alternately expands and closes its pectoral fins;” and Dr. Abel also supports this opinion, and says that it agrees with his experience; he has repeatedly seen the motion of the fins during flight, and as flight is only “swimming in air,” it appears natural that those organs should be used in the same manner in both elements. But the structure of a fin is not that of a wing; the pectoral fins or wings of the flying fish are simply enlarged fins, capable of supporting, perhaps, but not of propelling the animal in its flight.[12]
In fish, the organ of motion for propelling them through the water is the tail, and the fins direct their course; in birds, on the contrary, the wings are the organs of motion, and the tail the rudder. The only use of the extended pectoral fins in the fish is for the purpose of supporting the animal in the air, like a parachute, after it has leaped from the water by some power, which is possessed by fish of much larger size, even the whale. From the structure of the fin, I cannot consider it at all calculated for repeated percussions out of the water, although while in that fluid it continues its natural action uninjured, as it soon dries when brought into contact with the air, and the delicacy of the membrane between the rays would very readily become injured, were the organ similarly exerted in that medium.