In order to attain the astronomical knowledge which they seem to have possessed, the Babylonians must undoubtedly have employed a certain number of instruments. The invention of sun-dials, as already observed, is distinctly assigned to them. Besides these contrivances for measuring time during the day, it is almost certain that they must have possessed means of measuring time during the night. The clepsydra, or water-clock, which was in common use among the Greeks as early as the fifth century before our era, was probably introduced into Greece from the East, and is likely to have been a Babylonian invention. The astrolabe, an instrument for measuring the altitude of stars above the horizon, which was known to Ptolemy, may also reasonably be assigned to them. It has generally been assumed that they were wholly ignorant of the telescope. But if the satellites of Saturn are really mentioned, as it is thought that they are, upon some of the tablets, it will follow--strange as it may seem to us--that the Babylonians possessed optical instruments of the nature of telescopes, since it is impossible, even in the clear and vapor-loss sky of Chaldaea, to discern the faint moons of that distant planet without lenses. A lens, it must be remembered, with a fair magnifying power, has been discovered among the Mesopotamian ruins. A people ingenious enough to discover the magnifying-glass would be naturally led on to the invention of its opposite. When once lenses of the two contrary kinds existed, the elements of a telescope were in being. We could not assume from these data that the discovery was made; but if it shall ultimately be substantiated that bodies invisible to the naked eye were observed by the Babylonians, we need feel no difficulty in ascribing to them the possession of some telescopic instrument. The astronomical zeal of the Babylonians was in general, it must be confessed, no simple and pure love of an abstract science. A school of pure astronomers existed among them; but the bulk of those who engaged in the study undoubtedly pursued it in the belief that the heavenly bodies had a mysterious influence, not only upon the seasons, but upon the lives and actions of men--an influence which it was possible to discover and to foretell by prolonged and careful observation. The ancient writers, Biblical and other, state this fact in the strongest way; and the extant astronomical remains distinctly confirm it. The great majority of the tablets are of an astrological character, recording the supposed influence of the heavenly bodies, singly, in conjunction, or in opposition, upon all sublunary affairs, from the fate of empires to the washing of hands or the paring of nails. The modern prophetical almanac is the legitimate descendant and the sufficient representative of the ancient Chaldee Ephemeris, which was just as silly, just as pretentious, and just as worthless.