INTO HOW MANY CIRCLES IS THE HEAVEN DISTINGUISHED; OR, OF THE DIVISION
OF HEAVEN.
Thales, Pythagoras, and the followers of Pythagoras do distribute the
universal globe of heaven into five circles which they denominate
zones; one of which is called the arctic circle, which is always
conspicuous to us, another is the summer tropic, another is the
equinoctial, another is the winter tropic, another is the antarctic
circle, which is always invisible. The circle called the zodiac is
placed under the three that are in the midst, and lies obliquely,
gently touching them all. Likewise, they are all cut in right angles
by the meridian, which runs from pole to pole. It is supposed that
Pythagoras made the first discovery of the obliquity of the zodiac, but
one Oenopides of Chios challenges to himself the invention of it.