which possesses more than common interest. If
the classical writers were correct in their belief that Chaldaea was
the birthplace of Astronomy, and that their own astronomical science was
derived mainly from this quarter, it must be well worth inquiry what the
amount of knowledge was which the Babylonians attained on the subject,
and what were the means whereby they made their discoveries.

On the broad flat plains of Chaldsea, where the entire celestial
hemisphere is continually visible to every eye, and the clear
transparent atmosphere shows night after night the heavens gemmed with
countless stars, each shining with a brilliancy unknown in our moist
northern climes, the attention of man was naturally turned earlier than
elsewhere to these luminous bodies, and attempts were made to grasp, and
reduce to scientific form, the array of facts which nature presented to
the eye in a confused and tangled mass. It required no very long course
of observation to acquaint men with a truth, which at first sight none
would have suspected--namely, that the luminous points whereof the sky
was full were of two kinds, some always maintaining the same position
relatively to one another, while others were constantly changing their
places, and as it were wandering about the sky. It is certain that the
Babylonians at a very early date distinguished from the fixed stars
those remarkable five, which, from their wandering propensities, the
Greeks called the "planets," and which are the only erratic stars that
the naked eye, or that even the telescope, except at a very high power,
can discern. With these five they were soon led to class the Moon, which
was easily observed to be a wandering luminary, changing her place among
the fixed stars with remarkable rapidity. Ultimately, it came to be
perceived that the Sun too rose and set at different parts of the year
in the neighborhood of different constellations, and that consequently
the great luminary was itself also a wanderer, having a path in the sky
which it was possible, by means of careful observation, to mark out.

But to do this, to mark out with accuracy the courses of the Sun and
Moon among the fixed stars, it was necessary, or at least convenient, to
arrange the stars themselves into groups. Thus, too, and thus only, was
it possible to give form and order to the chaotic confusion in which
the stars seem at first sight to lie, owing to the irregularity of
their intervals, the differenc