Under the Maples by John Burroughs

It was "the divine Kepler," as Professor Shaler calls him, who looked upon the earth as animated in the fashion of an animal. "To him this world is so endowed with activities that it is to be accounted alive. " But his critics looked upon this fancy of Kepler's as proof of a disordered mind.

Now I read in a work of George Darwin's (son of the great naturalist) on the tides that the earth in many ways behaves more like a living organism than like a rigid insensate sphere. Its surface throbs and palpitates and quivers and yields to pressure as only living organisms do. The tides can hardly be regarded as evidences of its breathing, as Kepler thought they could, but they are proof of how closely it is held in the clasp of the heavenly forces. It is like an apple on the vast sidereal tree, that has mellowed and ripened with age. Our moon is no doubt as dead as matter can be. It is hard to fancy its surface yielding to our tread as does that of the earth. Then we know that the absence of air and water on it is proof that it cannot be endowed with what we call life. George Darwin tells us that when we walk on the ground we warp and bend the surface very much as we might bend or dent the epidermis of a colossal pachyderm. He and his brother devised an instrument by which the slight fluctuations of the ground, as we move over it, could be measured. The instrument was so delicate that it revealed the difference of effect produced by the same pressure at seven feet and at six feet from the instrument! More than that, the instrument revealed the throbbing and agitations which the ground is undergoing at all times. They found that minute earthquakes, or microseisms, as the Italians call them, are occurring constantly.