Personal Narrative Of Travels To The Equinoctial Regions Of America During The Years 1799-1804 - Volume 1 - By Alexander Von Humboldt And Aime Bonpland.
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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.
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