The ocean world : being a descriptive history of the sea and its living inhabitants / Chiefly translated from "La vie et les moeurs des animaux".

  • Louis Figuier
Date:
1868
Catalogue details

Licence: Public Domain Mark

Credit: The ocean world : being a descriptive history of the sea and its living inhabitants / Chiefly translated from "La vie et les moeurs des animaux". Source: Wellcome Collection.

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    It is true that, in consequence of its great distance, this only amounts to a thirty-eight-hundredth part of that of the earth’s satellite. The inequality which exists between the solar and lunar days—the latter exceeding the first by fifty-four minutes—has also the effect of adding to or subtracting from this force alternately. When the sun and moon are in conjunction (Fig. 6), or in opposition, that is to say, placed upon the same right line, their attraction on the sea is com- bined, and a spring tide is produced. This happens at the period of the syzygies—the period of new and full moon. At the period of the quadrature, or the first and last quarters, the solar action, being The Sun. qrposed to that of lunar attraction, tends to produce a sensibly weaker These effects are never produced instantaneously - but, the impulse rnMgmsi, ]t WlH continue to influence the tides for two or three days he highest and lowest tides being nearly in the proportion of 138 to 63’ ir° ! to The highest tides occur at the equinoxes, when the noon is m perigee; the lowest at the solstices, when it is in apogee n our ports, and along the coast, the water rises twice in twentv-fimr lours, when it is said to be high water; when it retires, it is low ™er: they are respectively the flux and reflux of the waves The tide is retarded every day about fifty minutes, the lunar day