From certain passages in the astrological tablets, Thompson draws the interesting conclusion that the Chaldean astronomers were acquainted with some kind of a machine for reckoning time. He finds in one of the tablets a phrase which he interprets to mean measure-governor, and he infers from this the existence of a kind of a calculator. He calls attention also to the fact that Sextus Empiricus[13] states that the clepsydra was known to the Chaldeans, and that Herodotus asserts that the Greeks borrowed certain measures of time from the Babylonians. He finds further corroboration in the fact that the Babylonians had a time-measure by which they divided the day and the night; a measure called kasbu, which contained two hours. In a report relating to the day of the vernal equinox, it is stated that there are six kasbu of the day and six kasbu of the night.

While the astrologers deduced their omens from all the celestial bodies known to them, they chiefly gave attention to the moon, noting with great care the shape of its horns, and deducing such a conclusion as that "if the horns are pointed the king will overcome whatever he goreth," and that "when the moon is low at its appearance, the submission (of the people) of a far country will come."[14] The relations of the moon and sun were a source of constant observation, it being noted whether the sun and moon were seen together above the horizon; whether one set as the other rose, and the like. And whatever the phenomena, there was always, of course, a direct association between such phenomena and the well-being of human kind - in particular the king, at whose instance, and doubtless at whose expense, the observations were carried out.

From omens associated with the heavenly bodies it is but a step to omens based upon other phenomena of nature, and we, shall see in a moment that the Babylonian prophets made free use of their opportunities in this direction also. But before we turn from the field of astronomy, it will be well to inform ourselves as to what system the Chaldean astronomer had invented in explanation of the mechanics of the universe. Our answer to this inquiry is not quite as definite as could be desired, the vagueness of the records, no doubt, coinciding with the like vagueness in the minds of the Chaldeans themselves. So far as we can interpret the somewhat mystical references that have come down to us, however, the Babylonian cosmology would seem to have represented the earth as a circular plane surrounded by a great circular river, beyond which rose an impregnable barrier of mountains, and resting upon an infinite sea of waters. The material vault of the heavens was supposed to find support upon the outlying circle of mountains. But the precise mechanism through which the observed revolution of the heavenly bodies was effected remains here, as with the Egyptian cosmology, somewhat conjectural. The simple fact would appear to be that, for the Chaldeans as for the Egyptians, despite their most careful observations of the tangible phenomena of the heavens, no really satisfactory mechanical conception of the cosmos was attainable. We shall see in due course by what faltering steps the European imagination advanced from the crude ideas of Egypt and Babylonia to the relatively clear vision of Newton and Laplace.