The ocean / By P. H. Gosse.

  • Gosse, Philip Henry, 1810-1888.
Date:
[pref. 1845]
Catalogue details

Licence: Public Domain Mark

Credit: The ocean / By P. H. Gosse. Source: Wellcome Collection.

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    tides to more than one-fourth of the moon’s extent. When the power of these luminaries is exerted in the same direction, the result is a higher elevation, called the spring tide; and for the reason already explained, the same occurs when they are in oppo- site quarters of the heavens. On the other hand, when they are in quadrature, that is, when appa- rently separated by just one-fourth of the heavens, the influence of the sun neutralizes, in the ratio of one-fourth, that of the moon, and hence we have the lowest tides, called neap-tides, soon after the first and third quarters of the moon. Local circumstances greatly affect, not only the time but also the height of the tides. In some long bays, which grow gradually narrower, in the form of a funnel, the whole of the increased water which en- tered the mouth of the bay, being confined within very narrow limits, rises rapidly to a great height. Near Chepstow, in the Bristol Channel, for example, the tide rises from 45 to 60 feet, and on one oc- casion after a strong westerly gale, it even reached to 70 feet. Again, in the Bay of Fundy, in North America, the spring tides sometimes rise to the astonishing elevation of 120 feet. At the mouths of some large rivers, where the shore is very level to a considerable distance inland, the tide rolls in under the form of one vast wave, which is called the bore : something of this kind occurs in Solway Frith on our own coast, and it is said, that if, when the tide is coming in, a man upon a swift horse were placed at the water’s edge, and bidden to ride for his life, the utmost efforts of his steed would not preserve