Page:The Music of the Spheres.djvu/308

 has no class of his own, but belongs to the class Mammalia, along with the quadrupeds. Neither has he an order of his own, but belongs to the order of the Primates, along with the monkeys, lemurs, etc. Even a family of his own, the Hominidae, is grudgingly admitted by some. But from a psychical point of view it is simply impossible to overestimate the space which separates man from all lower things. Man must be set off not only against the whole animal kingdom, but against the whole book of Nature besides, as an equivalent: Nature the Book—the revelation—and man the interpreter. So in the history of the earth: from one point of view the era of man is not equivalent to an era, nor to an age, nor to a period, nor even to an epoch. But from another point of view it is the equivalent of the whole geological history of the earth besides. For the history of the earth finds its consummation, and its interpreter, and its significance, in man."

Ah—how exhilarating the thought! Once again with the astronomer, we gaze out on the huge planets of the solar system,—the groups and great galaxies of stars. Does the earth really seem so insignificant in its smallness?

The beautiful little earth-ball, with its precious freight of human beings, softly flies about the sun. Amply protected in a transparent case of atmosphere, it completes its tremendous journey of 576,000,000 miles once every year. During this year its temperature is varied by four seasons which are caused by the earth being inclined 23½ degrees on its axis.

During this journey around the sun, the earth rotates 366¼ times on its axis, making one revolution every 23 hours, 56 minutes and 4.09 seconds. This causes each side to be alternately warmed and lighted every few hours. Cupped close to the darkened hemisphere lies a huge cone of shadow which extends out in space past