On Jun 17, 4:41 pm, Jim Higgins wrote:
On Sat, 16 Jun 2007 16:31:03 -0500, Cecil Moore
This is similar to the problem that John Harrison faced
when he tried to design a clock for ocean travel. The
frame of reference was continuously changing so he had
to give up on his original design.

Huh? I recall the story quite differently. He had to give up on his
original design because it wasn't immune to the gyroscopic effect
resulting from rotation of the earth and pitching of the ship.

i.e. a changing (physical) frame of reference.
--
73, Cecil, w5dxp.com