316. Though all opake bodies on which the Sun shines have their shadows,
yet such is the bulk of the Sun, and the distances of the Planets, that
the primary Planets can never eclipse one another. A Primary can eclipse
only it’s secondary, or be eclipsed by it; and never but when in
opposition or conjunction with the Sun. The primary Planets are very
seldom in these positions, but the Sun and Moon are so every month:
whence one may imagine that these two Luminaries should be eclipsed
every month. But there are few Eclipses in respect of the number of New
and Full Moons; the reason of which we shall now explain.
[Sidenote: Why there are so few Eclipses.
The Moon’s Nodes.