Poles or stone pillars to mark off the day by the direction and length of the shadow

When men began to stick up poles or stone pillars to mark off the day by the direction and length of the shadow, they would notice that the noon shadow always points to the same spot on the horizon, and that the Pole Star remains throughout the night exactly above it. As the night passed they would see the other stars revolve about the Pole Star in an anti-clockwise direction, from east to west above it, like the sun. They would long since have known that star clusters nearest the pole, the "circumpolar" stars, never sink below the horizon, trailing from west to east below the pole, and from east to west above it. As the noon shadow divided the day, the signal of midnight would be when a star cluster, rising at sunset on the eastern horizon and setting at sunrise on the western horizon, was directly above the pole. These clusters or "constellations" received fanciful names redolent with the preoccupations of everyday life in an agrarian economy. Herdsmen watching the night pass would find it just as easy to recognize intervals of night time equivalent to the shadow hours of the day. The much despised yokel, who has not upholstered his brain with the urban superstitions of all the ages, is often adept in using the star clock. A little practice while camping out is sufficient to enable you to tell the time by the stars with an error scarcely more than quarter of an hour.

Centuries before city life began, man had begun to fumble for a connected account of the regularities forced on his attention. He already knew that sun, moon, and stars partake of the same daily and nightly motion about one central point in the heavens. As they stand, the facts with which primitive man was familiar in his everyday life are capable of being looked at in two ways. When we are passing another train, we cannot at once tell whether we are at rest and the other one is in motion, or vice versa. So we cannot tell whether we are going east to meet the sun and rising stars, or whether they are moving west to meet us. In the train we can settle the issue by looking out of the opposite window. We put ourselves in the position of the man on the platform. Primitive man had no knowledge of what the two trains would look like from the platform. Having no other court of appeal, he inclined to his first impression that the sun and stars were rushing past him.

In the priestly lore of the earliest calendar civilizations the picture pieced together was something like this. The stars, moon, and sun were all on the surface of a great sphere, of which we only see one half at a time. The stars become visible when the sun is in the celestial hemisphere below our horizon. The celestial sphere revolves around an axis joining the Pole Star to some fixed spot on the earth -- the North Pole, as we call it today. It completes its revolution in a day and a night, revolving in an anti-clockwise direction from the standpoint of a person looking upwards towards the North Pole Star.