Copernicus places the sun in the centre of our system, the fixed stars
at the circumference, and the earth and other planets in the intervening
space; and he ascribes to the earth not only a diurnal motion around its
axis, but an annual motion round the sun. This simple system, which
explains all the appearances of the planets and their situations,
whether processional, stationary, or retrograde, was so fully and
distinctly inculcated by the ancients, that it is matter of surprise it
should derive its name from a modern philosopher.
Pythagoras thought that the earth was a movable body, and, so far from
being the centre of the world, performed its revolutions around the
region of fire, that is the sun, and thereby formed day and night. He is
said to have obtained this knowledge among the Egyptians, who
represented the sun emblematically by a beetle, because that insect
keeps itself six months under ground, and six above; or, rather,
because having formed its dung into a ball, it afterwards lays itself on
its back, and by means of its feet whirls that ball round in a circle.
Philolaüs, the disciple of Pythagoras, was the first publisher of that
and several other opinions belonging to the Pythagorean school. He
added, that the earth moved in an oblique circle, by which, no doubt, he
meant the zodiac.
Plutarch intimates, that Timæus Locrensis, another disciple of
Pythagoras, held the same opinion; and that when he said the planets
were animated, and called them the different measures of time, he meant
no other than that they served by their revolutions to render time
commensurable; and that the earth was not fixed to a spot, but was
carried about by a circular motion, as Aristarchus of Samos, and
Seleucus afterwards taught.
This Aristarchus of Samos, who lived about three centuries before Jesus
Christ, was one of the principal defenders of the doctrine of the
earth’s motion. Archimedes informs us, “That Aristarchus, writing on
this subject against some of the philosophers of his own age, placed the
sun immovable in the centre of an orbit, described by the earth in its
circuit.” Sextus Empiricus cites him, as one of the principal supporters
of this opinion.
From a passage in Plutarch it appears, that Cleanthes accused
Aristarchus of impiety and irreligion, by troubling the repose of Vesta
and the Larian gods; when, in giving an account of the phenomena of the
planets in their courses, he taught that heaven, or the firmament of the
fixed stars, was immovable, and that the earth moved in an oblique
circle, revolving at the same time around its own axis.
Theophrastus, as quoted by Plutarch, says in his History of Astronomy,
which has not reached our times, that Plato, when advanced in years,
gave up the error he had been in, of making the sun turn round the
earth; and lamented that he had not placed it in the centre, as it
deserved, instead of the earth, which he had put there contrary to the
order of nature. Nor is it at all strange that Plato should reassume an
opinion which he had early imbibed in the schools of the two celebrated
Pythagoreans, Archytas of Tarentum, and Timæus the Locrian, as we see in
St. Jerome’s Christian apology against Rufinus. In Cicero we find, that
Heraclides of Pontus, who was a Pythagorean, taught the same doctrine.
It may be added, that Tycho Brache’s system was known to Vitruvius, as
well as were the motions of Venus and Mercury about the sun.
That the earth is round, and inhabited on all sides, and of course that
there are Antipodes, or those whose feet are directly opposite to ours,
is one of the most ancient doctrines inculcated by philosophy. Diogenes
Laertius, in one part of his history, says, that Plato was the first who
called the inhabitants of the earth opposite to us “Antipodes.” He does
not mean that Plato was the first who taught this opinion, but only the
first who made use of the term “Antipodes;” for, in another place, he
mentions Pythagoras as the first who taught of When Plutarch wrote, it
was a point in. controversy; and Lucretius and Pliny, were oppose this
notion, as well as St. Augustine, serve as witnesses that it must have
prevailed in their time.
The proofs which the ancients brought of the sphericalness of the earth,
were the same that the moderns use. Pliny on this subject observes, that
the land which retires out of sight to persons on the deck of a ship,
appears still in view to those who are upon the mast. He thence
concludes, that the earth is round. Aristotle drew this consequence not
only from the circular shadow of the earth on the disk of the moon in
eclipse, but also from this, that, in travelling south, we discover
other stars, and that those which we saw before, whether in the zenith
or elsewhere, change their situation with respect to us.
On whatever arguments the ancients founded their theory, it is certain
they clearly apprehended that the planets revolved upon their own axis.
Heraclides of Pontus, and Ecphantus, two celebrated Pythagoreans, said,
that the earth turned from west to east, just as a wheel does upon its
axis or centre. According to Atticus, the platonist, Plato extended this
observation from the earth to the sun and other planets. “To that
general motion which makes the planets describe a circular course, he
added another, resulting from their spherical shape, which made each of
them move about its own centre, whilst they performed the general
revolution of their course.” Plotinus also ascribes this sentiment to
Plato; for speaking of him he says, that besides the grand circular
course observed by all the stars in general, Plato thought “they each
performed another about their own centre.”
The same notion is ascribed to Nicetas of Syracuse by Cicero, who quotes
Theophrastus to warrant what he advances. This Nicetas is he whom
Diogenes Laertius names Hycetas, whose opinion, he says, was, that “the
celerity of the earth’s motion about its own axis, and otherwise, was
the only cause and reason of the apparent revolutions of the heavenly
bodies.”
How useful the invention of telescopes has been to the astronomical
observations of the moderns is particularly evident from their
discovery, that the planets revolve on their axis, a discovery founded
on the periodical revolution of the spots observed on their disks; so
that every planet performs two revolutions, by one of which it is
carried with others about a common centre; and, by the other, moves upon
its axis round its own. Yet all that the moderns have advanced in this
respect, serves only to confirm to the ancients the glory of being the
first discoverers, by the aid of reason alone. The moderns in this are
to the ancients, as the French philosophers to sir Isaac Newton; all
whose labours and travail, in visiting the poles and equator to
determine the figure of the earth, served only to confirm what sir Isaac
had thought of it, without so much as stirring from his closet.
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