We know from Newton’s First Law of Motion that a body remains in its state of rest or of uniform motion unless acted upon by some external force. If the movement of matter were governed only by that law, my master’s skull would at this very moment be sharing the fate of Aeschylus, so he was fortunate that Newton was kind enough to save him from such a shattering experience by the establishment of a Second Law to the effect that change in motion is proportional to, and in the same direction as, the applied force.
