The Zodiacal constellations at any rate, or those through which the sun's course lies would seem to have had this origin; and many of them may be distinctly recognized on Babylonian monuments which are plainly of a stellar character.

The accompanying representation, taken from a conical black stone in the British Museum [PLATE XX., Fig.

2.], and belonging to the twelfth century before our era, is not perhaps, strictly speaking, a zodiac, but it is almost certainly an arrangement of constellations according to the forms assigned them in Babylonian uranography.

[PLATE XXI.] The Ram, the Bull, the Scorpion, the Serpent, the Dog, the Arrow, the Eagle or Vulture may all be detected on the stone in question, as may similar forms variously arranged on other similar monuments.
[Illustration: PLATE XXI.] The Babylonians called the Zodiacal constellations the "Houses of the Sun," and distinguished from them another set of asterisms, which they denominated the "Houses of the Moon." As the Sun and Moon both move through the sky in nearly the same plane, the path of the Moon merely crossing and recrossing that of the Sun, but never diverging from it further than a few degrees, it would seem that these "Houses of the Moon," or lunar asterisms, must have been a division of the Zodiacal stars different from that employed with respect to the sun, either in the number of the "Houses," or in the point of separation between "House" and "House." The Babylonians observed and calculated eclipses; but their power of calculation does not seem to have been based on scientific knowledge, nor to have necessarily implied sound views as to the nature of eclipses or as to the size, distance, and real motions of the heavenly bodies.
The knowledge which they possessed was empirical.

Their habits of observation led them to discover the period of 223 lunations or 18 years 10 days, after which eclipses--especially those of the the moon--recur again in the same order.