t; but this he did not demonstrate, and his whole
system was unscientific, assuming certain arbitrary principles, from
which he reasoned deductively. "He assumed that fire is more worthy than
earth; that the more worthy place must be given to the more worthy; that
the extremity is more worthy than the intermediate parts,--and hence,
as the centre is an extremity, the place of fire is at the centre of the
universe, and that therefore the earth and other heavenly bodies move
round the fiery centre." But this was no heliocentric system, since the
sun moved, like the earth, in a circle around the central fire. This was
merely the work of the imagination, utterly unscientific, though bold
and original. Nor did this hypothesis gain credit, since it was the
fixed opinion of philosophers that the earth was the centre of the
universe, around which the sun, moon, and planets revolved. But the
Pythagoreans were the first to teach that the motions of the sun, moon,
and planets are circular and equable. Their idea that the celestial
bodies emitted a sound, and were combined into a harmonious symphony,
was exceedingly crude, however beautiful "The music of the spheres"
belongs to poetry, as well as to the speculations of Plato.

Eudoxus, in the fifth century before Christ, contributed to science by
making a descriptive map of the heavens, which was used as a manual of
sidereal astronomy to the sixth century of our era.

The error of only one hundred and ninety days in the periodic time of
Saturn shows that there had been for a long time close observations.
Aristotle--whose comprehensive intellect, like that of Bacon, took in
all forms of knowledge--condensed all that was known in his day into a
treatise concerning the heavens. He regarded astronomy as more
intimately connected with mathematics than any other branch of science.
But even he did not soar far beyond the philosophers of his day, since
he held to the immobility of the earth,--the grand error of the
ancients. Some few speculators in science (like Heraclitus of Pontus,
and Hicetas) conceived a motion of the earth itself upon its axis, so as
to account for the apparent motion of the sun; but they also thought it
was in the centre of the universe.

The introduction of the gnomon (time-pillar) and dial into Greece
advanced astronomical knowledge, since they were used to determine the
equinoxes and solstices, as well as parts of the day. Meton set up a
sun-dial at Athens in th