Page:The Gradual Acceptance of the Copernican Theory of the Universe.djvu/135

 Nor is it moved by any other that may move the earth; as that which moves the earth could not at the same time and with like motion move the air. For since the air is different from the earth in essence, in both active and passive qualities, and in kind of substance, it can not receive the impelling force of the acting body, or that force applied in the same way as the earth, and so could not be moved in the same way. The virtues [of bodies] acting and of moving diversely are received by the recipients according to the diversity of their dispositions. Also it can not be moved by the earth; since if it were moved by the earth, it must be said to be moved by force, but such motion appears to be impossible. Ergo. The minor premise is proved: for if air is thus moved by the earth by force the air ought to be moved more rapidly than the earth, because air is larger [than the earth].

For what is outside is larger than what is inside. When, however, what is larger and what is outside is driven around equally rapidly with what is less and what is inside, then the former is moved much more rapidly. Thus it is true that the sphere of Saturn in its daily course is moved far faster than the sphere of the moon. But it is impossible that the one driven should move more rapidly than the one driving; therefore the air is not moved by the earth's violence. Thus would it be if the air were moved with the earth, or by itself, or by force. Thus far, then, the force of the original argument remains; since of its own motion, indeed, it could not be in every way conformable to the motion of the earth as I have shown; and this because the air differs from the earth in consistency of substance, in qualities and in essence. But the air ought at all events to move more sluggishly than the earth. It follows from this that an arrow shot straight up could not return to its starting point; for the earth, moving like the air, on account of the other's slower rate leaves it behind, and the arrow also which is carried away from it.

Besides, if the air does not move so rapidly as the earth, a man living in a very high tower, however quiet the air, ought then always to feel the strongest wind and the greatest disturbance of the air.

Since mountains and towers are moved with the earth, and the air would not be accompanying them at an equal speed, it would necessarily follow that they would precede the air by cleaving and cutting and ploughing through it which ought to make a great wind perceptible.

Eighthly; if a person stood in some very high tower or other high place and aimed from that tower at some spot of earth perpendicularly below his eye, and allowed a very heavy stone to 127