COMPENDIOSA.

Of this matter, let us take an example in the two most illustrious planets, the Sun and the Moon.

At the New Moon original: "Nouilunio", when the Moon is closest to the Sun, it can be sufficiently observed that it is carried along together with the Sun toward the west by that impulse of which we have spoken, and it completes this motion in twenty-four hours. Nevertheless, we see not obscurely that the Moon itself, as much as it grows, also departs from the Sun toward the east; and it withdraws gradually in such a way that on the fourteenth day, when the Moon is full, it appears in the east at the same hour that the Sun sets. This occurs by that motion which is said to be its own.

And by a similar type of motion, all the Planets follow the signs of the Zodiac, each in its own order.

But besides the fact that experience itself teaches us abundantly about this motion, contrary to the aforementioned, it ought not seem strange that different motions occur to these orbs at the same time for different causes, since the same thing happens in other matters.

For imagine that I am placed at the stern of a ship; even if the ship is carried by a favorable current, nothing will prevent me from walking up toward the bow.

Furthermore, in what sense the Moon is said to grow or wane, we shall make clear later.

Therefore, the Planets have their own peculiar motion.