isfactory until the time of
Hipparchus. The primitive knowledge was almost nothing. The Homeric
poems regarded the earth as a circular plain bounded by the heaven,
which was a solid vault or hemisphere, with its concavity turned
downward. This absurdity was believed until the time of Herodotus, five
centuries after; nor was it exploded fully in the time of Aristotle. The
sun, moon, and stars were supposed to move upon or with the inner
surface of the heavenly hemisphere, and the ocean was thought to gird
the earth around as a great belt, into which the heavenly bodies sank at
night. Homer believed that the sun arose out of the ocean, ascended the
heaven, and again plunged into the ocean, passing under the earth, and
producing darkness. The Greeks even personified the sun as a divine
charioteer driving his fiery steeds over the steep of heaven, until he
bathed them at evening in the western waves. Apollo became the god of
the sun, as Diana was the goddess of the moon. But the early Greek
inquirers did not attempt to explain how the sun found his way from the
west back again to the east; they merely took note of the diurnal
course, the alternation of day and night, the number of the seasons, and
their regular successions. They found the points of the compass by
determining the recurrence of the equinoxes and solstices; but they had
no conception of the ecliptic,--of that great circle in the heaven
formed by the sun's annual course,--and of its obliquity when compared
with our equator. Like the Egyptians and Babylonians, the Greeks
ascertained the length of the year to be three hundred and sixty-five
days; but perfect accuracy was lacking, for want of scientific
instruments and of recorded observations of the heavenly bodies. The
Greeks had not even a common chronological era for the designation of
years. Herodotus informs us that the Trojan War preceded his time by
eight hundred years: he merely states the interval between the event in
question and his own time; he had certain data for distant periods. The
Greeks reckoned dates from the Trojan War, and the Romans from the
building of their city. The Greeks also divided the year into twelve
months, and introduced the intercalary circle of eight years, although
the Romans disused it afterward, until the calendar was reformed by
Julius Caesar. Thus there was no scientific astronomical knowledge worth
mentioning among the primitive Greeks.

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