In Feynman's "The Character of Physical Law," there is a nice brief
discussion of tides on pages 11 and 12 with both the physical concepts and
historical context discussed.
Dr. Lawrence D. Woolf; General Atomics; 3550 General Atomics Court, San
Diego, CA 92121; Phone:858-455-4475; FAX:858-455-4268; http://www.sci-ed-ga.org