"From a purely structural and animal point of view, man is very closely united with the animal kingdom. He has no department of his own, but belongs to the vertebrate department, along with the quadrupeds, birds, reptiles and fishes. He 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. "Some say, he bid his angels turn askance The poles of earth twice ten degrees or more From the sun's axle; they with labor push'd Oblique the centric globe." --_Milton's Paradise Lost._