TIDE

If the ocean were equally deep in every place, the ebbing and flowing of the tide would be universally regular and equal; but the shallowness of the water in many places, and the streightness of the channels, by which the tides may be considerably interrupted in some parts, and propagated in others, occasion a great diversity in their force and quantity. Hence, without an exact knowledge of all the circumstances of the several places where they happen to run, as of the portion of the land, the breadth and depth of channels, it is impossible to account for this diversity.

The theory of the tides is concisely described by a great author, in these words: "That motion of the water called tides is a rising and falling of the sea: the cause of this is the attraction of the moon, whereby the part of water in the great ocean which is nearest the moon, being most strongly attracted, is raised higher than the rest; and the part opposite to it being least attracted, is also higher than the rest; and these two opposite elevations of the surface of the water in the great ocean, following the motion of the moon from east to west, and striking againt the large coasts of the continents, from thence rebounds back again, and so makes floods and ebbs in narrows, seas, and rivers." Locke. Irregular TIDE, (Débauche.)

With regard to the relative force of the tide on a ship floating therein, it is already explained in the article CURRENT.

Reference Works