Читать книгу Life at the Zoo: Notes and Traditions of the Regent's Park Gardens онлайн

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The possibility of exhibiting the powers of electrical fishes in the tanks at the Zoo, suggests the question whether, in the progress of marine aquariums, we shall ever see the luminous creatures of the deep seas exhibited alive before air-breathing mortals in this upper world. Virgil’s Sybil set the depth of Tartarus at twice the skyward gaze to the summit of Olympus. But the profundity of the ocean abyss is such that in the deep Atlantic Olympus might be imposed upon itself, and Ossa piled above, without rising to break the surface. The imagination almost refuses to grasp the physical conditions in an abyss so profound as the ocean bed off the coast of Porto Rico, wrapped, by a weight of waters five miles deep, in perpetual darkness and everlasting cold, and under a pressure of which figures can convey no practical conception. Even at the average depth of 2,500 fathoms sunlight can never penetrate. The temperature is only a few degrees above freezing-point, the water is without movement, there is no plant-life, and the pressure is two and a half tons on the square inch, or about twenty-five times greater than that which drives a railway train. Yet it is now certain that where the fancy painted a survival of the sterile and lifeless plains of an unformed world, or at most the rude survivals of primitive fossils, the bed of the deep sea teems with animal life, and the clinging darkness of its waters is peopled by myriads of fragile and fantastic forms, and lighted into a blaze by the effulgence from their bodies. Hard as it is to conceive the bare existence of life under the conditions of the ocean abyss, the mind pauses in astonishment at the completeness of the triumph by which creatures apparently doomed to live in eternal night are supplied not with mere slimy secretions of luminosity, but with rows of bright and ever-burning lamps, in organs fitted with lenses and reflectors, which shoot their beams sidelong through the circumfluent ocean, or project shafts of light before their eyes to illuminate their path.