Nicole Oresme considered Jean Buridan's idea that impetus is slowly "used up" as objects move, developing a theory that suggests how different motions might be related. In the following passage he compared the swing of a pendulum to the motion of a stone traveling back and forth in a hole through the center of the earth:

I posit that the earth is pierced clear through and that we can see through a great hole farther and farther right up to the other end where the antipodes would be if the whole earth were inhabited; I say, first of all, that if we dropped a stone through the hole, it would pass beyond the center of the earth, going straight on toward the other side for a certain limited distance and that then it would turn back going beyond the center on...