e fixed stars,
are both to be classed among the discoveries of prehistoric ages. Nor is
it to be said that these achievements related to matters of an obvious
character. Ancient astronomy may seem very elementary to those of the
present day who have been familiar from childhood with the great truths
of nature, but, in the infancy of science, the men who made such
discoveries as we have mentioned must have been sagacious philosophers.

Of all the phenomena of astronomy the first and the most obvious is that
of the rising and the setting of the sun. We may assume that in the dawn
of human intelligence these daily occurrences would form one of the
first problems to engage the attention of those whose thoughts rose
above the animal anxieties of everyday existence. A sun sets and
disappears in the west. The following morning a sun rises in the east,
moves across the heavens, and it too disappears in the west; the same
appearances recur every day. To us it is obvious that the sun, which
appears each day, is the same sun; but this would not seem reasonable to
one who thought his senses showed him that the earth was a flat plain of
indefinite extent, and that around the inhabited regions on all sides
extended, to vast distances, either desert wastes or trackless oceans.
How could that same sun, which plunged into the ocean at a fabulous
distance in the west, reappear the next morning at an equally great
distance in the east? The old mythology asserted that after the sun had
dipped in the western ocean at sunset (the Iberians, and other ancient
nations, actually imagined that they could hear the hissing of the
waters when the glowing globe was plunged therein), it was seized by
Vulcan and placed in a golden goblet. This strange craft with its
astonishing cargo navigated the ocean by a northerly course, so as to
reach the east again in time for sunrise the following morning. Among
the earlier physicists of old it was believed that in some manner the
sun was conveyed by night across the northern regions, and that darkness
was due to lofty mountains, which screened off the sunbeams during the
voyage.

In the course of time it was thought more rational to suppose that the
sun actually pursued his course below the solid earth during the course
of the night. The early astronomers had, moreover, learned to recognise
the fixed stars. It was noticed that, like the sun, many of these stars
rose and set in consequence of the diurnal movem