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106 THE OCEAN. CHAPTER XIII. APPARENT IRREGULARITIES OF THE TIDES.—EXTRAORDINARY SIZE OF THE TIDAL WAVE IN CERTAIN BAYS. INTERFERENCE OF EBB AND FLOW.— DIURNAL TIDES.—INEQUALITIES OF SUCCESSIVE TIDES. Innumerable are the apparent inequalities which occur in the phenomena of the tides, in consequence of the inequalities of the submarine surface, the thousand indentations of the shore, and the alternations of winds and currents. Though the cause of the movement be the same everywhere, we can still say that at no point of the sea do the ebb and flow present a perfect agreement in their progress. Each promontory, each islet, each rock is bathed by waters having a distinct rule in the Figs. 32-34.—Irregularities in the Curves of the Tidal Waves resulting from the Form of the Sea-bed, projecting Rocks, etc. (after Lubbock). propagation of their tides; every obstacle which breaks the regular course of the oscillations modifies the whole of the graceful curves which bend around it. The above figures, borrowed from Lubbock, give an idea of these variations in the march of the waves. The difference which most strikes the minds of navigators and inhabitants of the coast is that of the height of the fides. In one part of the coast the tide hardly makes itself felt, even during the equinoctial syz- ygies; while elsewhere every tide is a real deluge, spreading as far as the eye can see over vast tracts, which emerge again at the time of ebb. This astonishing contrast in the amplitude of the tides results from differences of speed in the progress of the oscillations in the seas and bays of the coast-line. In fact, the great swelling caused by the heavenly bodies may be considered as formed of a great number of successive waves occupying a considerable breadth on the surface of the sea. In the open ocean all these waves move with great speed; but in proportion as they approach the shores they slacken their movement, and consequently must gain in height what they lose in rapidity. From the mere sight of a tidal chart we can affirm that the tide will rise several feet high in all the gulfs
Title | The ocean, atmosphere, and life |
Creator | Reclus, Elisée |
Publisher | Harper |
Place of Publication | New York |
Date | 1873 |
Language | eng |
Type | Books/Pamphlets |
Title | 00000119 |
Type | Books/Pamphlets |
Transcript | 106 THE OCEAN. CHAPTER XIII. APPARENT IRREGULARITIES OF THE TIDES.—EXTRAORDINARY SIZE OF THE TIDAL WAVE IN CERTAIN BAYS. INTERFERENCE OF EBB AND FLOW.— DIURNAL TIDES.—INEQUALITIES OF SUCCESSIVE TIDES. Innumerable are the apparent inequalities which occur in the phenomena of the tides, in consequence of the inequalities of the submarine surface, the thousand indentations of the shore, and the alternations of winds and currents. Though the cause of the movement be the same everywhere, we can still say that at no point of the sea do the ebb and flow present a perfect agreement in their progress. Each promontory, each islet, each rock is bathed by waters having a distinct rule in the Figs. 32-34.—Irregularities in the Curves of the Tidal Waves resulting from the Form of the Sea-bed, projecting Rocks, etc. (after Lubbock). propagation of their tides; every obstacle which breaks the regular course of the oscillations modifies the whole of the graceful curves which bend around it. The above figures, borrowed from Lubbock, give an idea of these variations in the march of the waves. The difference which most strikes the minds of navigators and inhabitants of the coast is that of the height of the fides. In one part of the coast the tide hardly makes itself felt, even during the equinoctial syz- ygies; while elsewhere every tide is a real deluge, spreading as far as the eye can see over vast tracts, which emerge again at the time of ebb. This astonishing contrast in the amplitude of the tides results from differences of speed in the progress of the oscillations in the seas and bays of the coast-line. In fact, the great swelling caused by the heavenly bodies may be considered as formed of a great number of successive waves occupying a considerable breadth on the surface of the sea. In the open ocean all these waves move with great speed; but in proportion as they approach the shores they slacken their movement, and consequently must gain in height what they lose in rapidity. From the mere sight of a tidal chart we can affirm that the tide will rise several feet high in all the gulfs |
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