THE TIDES

Every particle of matter attracts every other particle of matter throughout the entire Universe. The Sun and the Moon both exert a definite pull upon the earth; the moon particularly, being the earth’s satellite, is (so to say) held in place by the earth. The moon, exerting this definite pull, naturally influences the water of the earth most of all, because water is a fluid, mobile body. A heaping-up of the water then occurs—“high tide.” But the moon also attracts the earth to some extent; and the consequence of this is that the water on the opposite side of the globe is, as it were, left behind, which causes a heaping-up of the water there also. Hence, there are two high tides daily, with an interval of 12 hours between them, on opposite sides of the globe.

When the sun and moon pull together, we have the highest tides—“spring tides.” When they do not pull together (being in different parts of the heavens) we have only the surplus pull of the moon over the sun, and the tides are consequently not so high. These are the “neap tides.” All tides act as a sort of check or brake upon the rotation of the earth on its axis—tending to slow down its speed to some extent. “Tidal waves” are due to a combination of special causes.