eek the cause of the revolution,
or of other tendency of the Earth, from the sea surrounding it, or from the
motion of the air, or from the Earth's gravity, he would be no less silly
as a theorist than those who stubbornly ground their opinions on the
sentiments of the ancients. Ptolemy's reasonings are of no weight; for when
our true principles are laid down, the truth comes to light, and it is
superfluous to refute them. Let Costaeus recognize and philosophers see how
unfruitful and vain a thing it becomes then to take one's stand on the
principles and unproved opinions of certain ancients. Some raise a doubt
how it can be that, if the Earth move round its own axis, a globe of iron
or of lead dropped from the highest point of a tower falls exactly
perpendicularly to a spot of the Earth below itself. Also how it is that
cannon balls from a large culverin, fired with the same quantity and
strength of powder, in the same direction and at a like elevation through
the same air, would be cast at a like distance from a given spot both
Eastward and Westward, supposing the Earth to move Eastward. But those who
bring forward this kind of argument are being misled: not attending to the
nature of primary globes, and the combination of parts with their globes,
even though they be not adjoined by solid parts. Whereas the motion of the
Earth in the diurnal revolution does not involve the separation of her more
{229} solid circumference from the surrounding bodies; but all her effluvia
surround her, and in them heavy bodies projected in any way by force, move
on uniformly along with the Earth in general coherence. And this also takes
place in all primary bodies, the Sun, the Moon, the Earth, the parts
betaking themselves to their first origins and sources, with which they
connect themselves with the same appetence as terrene things, which we call
heavy, with the Earth. So lunar things tend to the Moon, solar things to
the Sun, within the orbes of their own effluvia. The emanations hold
together by continuity of substance, and heavy bodies are also united with
the Earth by their own gravity, and move on together in the general motion:
especially when there is no renitency of bodies in the way. And for this
cause, on account of the Earth's diurnal revolution, bodies are neither set
in motion, nor retarded; they do not overtake it, nor do they fall short
behind it when violently projected toward East or West.

[Illustration]

Let E F G