Evening Republican, Volume 14, Number 221, Rensselaer, Jasper County, 16 September 1910 — Cause of the Tides. [ARTICLE]

Cause of the Tides.

The tides are due wholly to the attractive force of the sun and moon. Every particle of matter composing the earth gravitates toward the moon inversely as the square of its distance. By the law of gravity the attractive force of the sun and moon decreases with the square of the distance. For that reason the nearer surface of the earth is attracted .with greater force and the further surface with lesser force than the center. The resultant effect is to cause a tendency to recede from the earth’s center in parts immediately under the sun or moon and also on the side most remote from them. The waters of the ocean are free to yield to this tendency and hence they tend to be heaped up into four tidal waves a day—two lunar and two solar. The lunar tides greatly predominate, the others being observable chiefly by their action in reinforcing or diminishing them. As the earth turns on Its axis these waves cause two principal alternations of high and low water every twentyfour hours in every part of the ocean, called flood tide and ebb tide. When the solar and lunar tides are in conjunction the maximum, or spring, tide takes place. When they are 90 degrees apart there oacurs the minimum tide.