essential to Matter, &c. %5

is overcome, though it resists no more to becarried on with that celerity, which is nowto be considered as its permanent state ; yetit resists as much to be out of this state, asit did formerly to be brought to it. Andthis is just the cafe in the descent of heavybodies; any velocity from the beginning ofthe fall would be a permanent state of thebody, if new impulses ah extra did notadd still farther degrees of velocity. Thistruth is also plain from this consideration,that if a body moving more swiftly thananother body moves by the force of gravi-ty, attraction, elasticity, &c. overtakes it;the body so overtaken will make resistanceto the impulse of the overtaking body, eventhough the direction of their motions con-spire. For instance, if we call the celeritywhich a piece of wood hath acquired infalling down through a certain space, K ;and the celerity, with which a bullet leavesthe muzzle of the gun, C ; and then sup-pose the bullet moving with the sum ofthese two celerities (Cst-K) to overtake thepiece of wood in the end of that space ; itis demonstrable that the bullet would piercethe wood, even though their motions were

conspiring.