26 A VIS INERTI AE

conspiring. For, the relative velocity ofthe ball and piece of wood being the same,both when it is discharged against the pieceof wood at rest, and when it overtakes itin its descent, the greatness of the stroke,and the effect of it will be the same; name-ly that the ball will pierce the wood. Onemay be also more familiarly certain of this,if he lets a ball drop out of his hand, andstrikes it before it reach the ground ; forhe will feel it resist the stroke very sensibly.This lets us fee that matter resists even theforce of gravity, or any other acting in thefame direction, as was asserted N° 5. andconsequently, by what was said in N° 15.that the force of gravity ( the same is to beunderjlood of elasticity , fuga , attraction,)is a force impressed ab extra , and no cona-tus, or tendency belonging to matter, or in-herent in it. But all this will still appearmore evidently when we come to considerwhat moment (impetus, or force in a mov-ing body) is: for all moment proceeds fromthe resistance in matter to change its slate ;and whatever matter hath force,^or moment ,in its motion, muss be resisting matter. Andconsequently matter resists to be moved by