Richard Feynman Messenger Lectures at Cornell The Character of Physical Law Part 1 The Law of Gravitation
In brief
The first of Richard Feynman's 1964 Messenger Lectures at Cornell, 'The Character of Physical Law', covering the law of gravitation. Feynman traces the history from Kepler and Newton to the universality of the inverse-square law. The recording is an older one with weak audio.