Therefore, we must say that the original mover gives the power of being a mover either to air or to water or to something else of the kind, naturally adapted for imparting and undergoing motion; but this thing does not cease simultaneously to impart motion and to undergo motion: it ceases to be in motion at the moment when its mover ceases to move it, but it still remains a mover, and so it causes something else consecutive with it to be in motion,