I Do Not Hesitate To Speak On A Subject Of Which Voyagers Discourse As Frequently As Of Dolphins, Sharks, Sea-Sickness, And The Phosphorescence Of The Ocean.

None of these topics can fail to afford interesting observations to naturalists, provided they make them their particular study.

Nature is an inexhaustible source of investigation, and in proportion as the domain of science is extended, she presents herself to those who know how to interrogate her, under forms which they have never yet examined.

I have named the flying-fish, in order to direct the attention of naturalists to the enormous size of their natatory bladder, which, in an animal of 6.4 inches, is 3.6 inches long, 0.9 of an inch broad, and contains three cubic inches and a half of air. As this bladder occupies more than half the size of the fish, it is probable that it contributes to its lightness. We may assert that this reservoir of air is more fitted for flying than swimming; for the experiments made by M. Provenzal and myself have proved, that, even in the species which are provided with this organ, it is not indispensably necessary for the ascending movement to the surface of the water. In a young flying-fish, 5.8 inches long, each of the pectoral fins, which serve as wings, presented a surface to the air of 3 7/16 square inches. We observed, that the nine branches of nerves, which go to the twelve rays of these fins, are almost three times the size of the nerves that belong to the ventral fins. When the former of these nerves are excited by galvanic electricity, the rays which support the membrane of the pectoral fin extend with five times the force with which the other fins move when galvanised by the same metals. Thus, the fish is capable of throwing itself horizontally the distance of twenty feet before retouching the water with the extremity of its fins. This motion has been aptly compared to that of a flat stone, which, thrown horizontally, bounds one or two feet above the water. Notwithstanding the extreme rapidity of this motion, it is certain, that the animal beats the air during the leap; that is, it alternately extends and closes its pectoral fins. The same motion has been observed in the flying scorpion of the rivers of Japan: they also contain a large air-bladder, with which the great part of the scorpions that have not the faculty of flying are unprovided. The flying-fish, like almost all animals which have gills, enjoy the power of equal respiration for a long time, both in water and in air, by the same organs; that is, by extracting the oxygen from the atmosphere as well as from the water in which it is dissolved. They pass a great part of their life in the air; but if they escape from the sea to avoid the voracity of the Dorado, they meet in the air the Frigate-bird, the Albatross, and others, which seize them in their flight.

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