Still, from the very first, there was one element of diversity in the year which must have struck all men, in the temperate and frigid zones at least, perhaps even in a certain way in the tropics. I mean, the varying length of the day, always perceptible in the frigid and temperate zones; for as soon as men in these regions began to think and to observe at all, they must have noticed that the days increased in their summer and lessened in their winter; and they must have learned to correlate this waxing and waning of the day with the appearance or abundance of certain fruits, seeds, birds, fishes, game, roots and other food stuffs. It is at least certain that all the world over men do now celebrate the solstices and the equinoxes as special feasts; and the close similarity in most such celebrations leads one to suspect that the custom has been handed down from the very remote time when the human family was still a single continuous body. In the tropics, it is true, the days vary so little that this difference in itself is not likely to have struck primæval man. But there, another point would come in--the annual movement of the sun overhead from south to north and _vice versa_; and though this would be less directly important to human life than in temperate regions, it would still be indirectly important. It would bring the rain with it. In Europe, of course, and in temperate America, we can see at once that the return of the sun northward must always have meant spring, the increase of food stuffs, the promise of corn or maize, the suggestion of harvest; and we can therefore understand why the midwinter feast, when the sun after his long journey south begins to move visibly north again, should have been both in pagan and Christian times the great festival of rejoicing for the men of the north temperate region. Day by day they saw the sun recede and the cold deepen; at last, one evening, he sets a little nearer, and they know that he has not deserted them forever. Similarly, the promise made at Yule begins to be realized at that other great feast of the spring equinox, which we still call in England by its ancient heathen title of Easter; the day by that time has got the better of the night, and "the sun dances on Easter Sunday" in commemoration of his completed victory over the combined powers of winter and darkness. In the tropics, on the other hand, the connection is less clear; but even here the shifting of the sun's apparent place is closely correlated with the shifting of the rain zone; and therefore it would not be long (after man was man) before tropical savages began to perceive a constant relation between the movements of the sun to north or south, and the occurrence of the fertilizing rainy season. We must remember that savages, with their improvident habits, are much more dependent upon rain than we are, and that magical ceremonies for breaking up a drought are among their commonest and most universally diffused superstitions.