Impetuses and moving bodies, with equal distances and objects, can create percussions variable to infinity.

That rebound is shorter which is born of a more powerful blow.

The lesser blow produces a longer rebound.

That percussion which is of greater power generates a rebound of lesser length.

The greater the percussion, the smaller the rebound; and the smaller the percussion, the longer its rebound.

The height of the rebound is understood to be that which the moving body makes from the line of the level of the struck site upward.

The length of the reflected motion is that which begins at the site of the percussion and ends at the beginning of the natural motion.

The central line of the weight is that which passes from the center of its gravity to the center of the world.

The central line of the motion of heavy bodies is that which passes through the center of the thickness of such motion and ends at the center of the magnitude of such body.

The central line of the blow is that which is born from the point of percussion of the moving body, passing through the middle of the weights, of which the upper is equal to the lower.

The center of gravity of bodies is always concentric with the central line of the thickness of its motion and of its magnitude, even though such body be irregular.

Motions are of three natures, that is: augmentative; the natural-observing, that of animals; and diminutive, that is, the violent.

The natural transverse motion ends at the beginning of the natural motion.

The weight m weighs more than the weight n, which strikes at r, and therefore m keeps n so burdened that it cannot rise up in its reflected motion.

That weight loads the pole of the pulley the less, whose cord that sustains it bends over that pulley with an obtuse angle of greater openness.

Let then the cord be a b which, being straight, is the limit of the last obtuse angle, and by what is said above this cord can give no weight to the aforesaid pulley; a g c gives less than a g d. Now in the right angle all the obtuse angles are ended, and in the acute angles no more weight is gained at the pole than double the weight suspended from that cord.

The cord, whether straight or bent, is always loaded with twice the weight it sustains.

The weight m is entirely at n, which at the site n weighs half its heaviness, as is shown in the upper figure of the quadrant. Therefore the weight sustained from m at n is one pound, and the weight of the resistance b, which is another pound, counts for one half at n, whence the pole c feels exactly one pound and a half.

The weight is entire throughout the whole length of the cord that sustains it, and entire in every part of it, not passing beyond the limit of more than a single bend.

Therefore the heavy body c is thus wholly, in potency, at b and at a, as it is at the site c itself. But although it is wholly at b, the pole of the pulley n feels only half of it on account of the attachment a, and on account of the real weight c it feels 1 whole. Therefore the pole n feels such weight one and a half times, and half of it it feels ...

Here it is a manifest thing that the pole feels twice the weight attached to it, and feels it along the central line of the world.

This one does not feel it twice along the central line of the world, but along the line of the half-obliquity h g.