only in the morning or at evening twilight, when it was noticed what bright star was visible near the horizon immediately before sunrise or after sunset. The apparent movement of the sun in the sky made itself manifest from the fact that the stars which were discernible in the western horizon shortly after sunset ceased to be visible after some days, the sun seeming to approach them, and that those observable in the eastern horizon shortly before sunrise gradually remained longer visible in the dawn, the sun appearing to recede from them.
In Egypt, for example, it was noticed that the overflowing of the Nile—which is the result of certain tolerably regular changes in the weather, caused by the position of the sun—always occurred on those days on which the bright light of Sirius was again visible in the morning twilight. In Greece it was likewise observed that those risings and settings of the Pleiades, of Orion, Arcturus, and others, which occurred in the morning or evening twilight, were related to certain yearly variations of heat, and to the directions of great atmospheric currents, and were, therefore, convenient guides in agriculture and navigation.
As the calendar advanced, however, in the predetermination of days and phenomena on which periods of human labor were dependent, the attention of the majority of men was diverted more and more from the direct observation of the moon, the sun, and stars, resting contented with what was stated in the calendar, so that even in the civilization of the present day an evening is accepted as clear if moonshine is set down in the almanac. The sun, moon, and stars, together with those other wandering bodies in the heavens, the planets, won a new significance through the origin of astrology, which advances in the following manner with the progress in calendar calculations:
The publication of arranged calendar matter and the constant improvement in the same were owing chiefly to the efforts of wise men, in early Greece, for instance, to the zealous labors of the priesthood at Delphi, who justly esteemed an established calendar a potent element of national unity and order, and as a means of security against the power and influence of those fostering secret teaching. Among other people, as the Romans, the selfish and ignorant priesthood deemed it for their interests to allow such determinations to remain in obscurity, or, on the ground of real or fictitious observations, to regulate the calendar as they desired. In fact, the influence of the seers and priests upon the people would be greatly lessened if the knowledge, which they had acquired of the times of revolution of heavenly bodies and the chronological periods dependent thereon, were to become the property of all; and this loss would be still more augmented, when the unavoidable inaccuracies of these public observations became after a time recognizable, rendering repeated changes in the calendar necessary, or when, in consequence of this, several systems of reckoning time strove for preference.
The difficulty lay chiefly in the fact that the light phases of the