Page:Mathematical collections and translations, in two tomes - Salusbury (1661).djvu/141

 instead of Aristotle, to prove that they do not.

This is proved by Aristotle in the same place, when he saith, that the natural motion of the parts is the right motion downwards to the centre of the Universe; so that the circular motion cannot naturally agree therewith.

But do not you see, that those very words carry in them a confutation of this solution?

How? and where?

Doth not he say that the circular motion of the Earth would be violent? and therefore not eternal? and that this is absurd, for that the order of the World is eternal?

He saith so.

But if that which is violent cannot be eternal, then by conversion, that which cannot be eternal, cannot be natural: but the motion of the Earth downwards cannot be otherwise eternal; therefore much lesse can it be natural: nor can any other motion be natural to it, save onely that which is eternal. But if we make the Earth move with a circular motion, this may be eternal to it, and to its parts, and therefore natural.

The right motion is most natural to the parts of the Earth, and is to them eternal; nor shall it ever happen that they move not with a right motion; alwayes provided that the impediments be removed.

You equivocate Simplicius; and I will try to free you from the equivoke. Tell me, therefore, do you think that a Ship which should sail from the Strait of Gibralter towards Palestina can eternally move towards that Coast? keeping alwayes an equal course?

No doubtlesse.

And why not?

Because that Voyage is bounded and terminated between the Herculean Pillars, and the shore of the Holy-land; and the distance being limited, it is past in a finite time, unlesse one by returning back should with a contrary motion begin the same Voyage anew; but this would be an interrupted and no continued motion.

Very true. But the Navigation from the Strait of Magalanes by the Pacifick Ocean, the Moluccha's, the Cape di buona Speranza, and from thence by the same Strait, and then again by the Pacifick Ocean, &c. do you believe that it may be perpetuated?

It may; for this being a circumgyration, which returneth about its self, with infinite replications, it may be perpetuated without any interruption.

A Ship then may in this Voyage continue sailing eternally.