Gravity, force, and percussion are of such a nature that each one by itself can be born of each of the others and also give birth to them. And all together, and each by itself, can create motion, and is born of it.

Gravity and force are to be called sisters and almost of the same nature, because they are generated from one and the same cause, live with the same desire, and are consumed by the same death.

Gravity and force, together with percussion, are not only to be called sisters and daughters and parents of one another, but sisters as well, because they are generated by motion and are the generators of that motion. But gravity and force have great similarity in many of their functions.

Gravity and force, together with percussion, are not only to be called mother and daughters of one another and sisters together, because they are generated by motion; but also generators of motion, because it cannot be created without them. But none of the said powers can, in equal motion, generate a power like itself.

Gravity and lightness are, in equal quantity, of equal power and equal in every function, save that they act to press by contrary motions.

Weight is overcome by force, and force by weight. Both are invisible, but their effects are well measurable. Both desire death.

Force, in dying, does not give birth to a blow, and where a blow is shown by it, there force is always alive. The blow is born of weight.

The more the weight moves toward its desire, the more it grows, and in this case the force diminishes.

Weight desires a single line, and force infinite ones.

Weight has its life of equal power, and force always weakens.

Weight passes by nature into all its supports, and is entire throughout the whole length of those supports, and entire in every part of them.

Weight remains in the body where it is born as long as that body stands outside its natural place, and force fails in the body where it is born.

The blow dies as soon as it is born.

Force will make weight and percussion. It will make weight when with it you raise a heavy body into the air; it will make the blow when you throw the stone by any motion.

Weight will make force in the crossbow, by drawing its cord back to the nut.

Weight will make percussion at the end of its motion.

Percussion makes force with wedges; it will make weight when it makes a heavy body leap through the air.

The multiple-superpartient ratios are these, namely:

double superbipartient of thirds,

triple supertripartient of quarters,

triple superquadripartient of fifths.