Description: A diagram from 1891 showing position of the earth, moon, and sun during spring and neap tide. "When the sun and moon act simultaneously, on the same hemisphere of the earth, as shown in Fig. 74, the tidal wave is higher than usual. The flood tides are then highest, and the ebb tides lowest. These are called spring tides. They occur twice during every revolution of the moon — once at full, and once at new moon. The highest spring tides occur a short time before the March and September equinoxes, when the sun is over the equator, and is nearest the earth. When, however, the sun and moon are 90° apart, or in quadrature, each produces a tide on the portion of the earth directly under it, diminishing somewhat that produced by the other body. High tide, then, occurs under the moon, while the high tide caused by the sun, becomes, by comparison, a low tide. Such tides are called neap tides. During their prevalence, the flood is not very high, nor the ebb very low. They occur twice each revolution of the moon, but are lowest about the time of the June and December solstices." — Houston, 1891, pp. 77-78.
Place Names: Solar System, Earth, Moon, Su
ISO Topic Categories: climatologyMeteorologyAtmosphere
Keywords: Position of the Earth, Moon, and Sun during Spring and Neap Tide, neap tide, water, climatologyMeteorologyAtmosphere, Unknown, 1891
Source: Edwin J. Houston, A. M. , The Elements of Physical Geography (Philadelphia, PA: Eldredge & Brother, 1891) 77
Map Credit: Courtesy the private collection of Roy Winkelman |
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