> from the earth's rotation, which is small, but this came later.) The Greeks
> noticed that the shadow of the earth on the moon during an eclipse was
> round, but I have no idea as to whether this did or could have given much
> evidence against the possibility of a highly prolate or oblate earth.
Don,
I believe that an additional part of the argument is that the shadow is
always round no matter where the moon is in the sky, suggesting that all
the earth's cross sections are circular.
Gordon Brown
Department of Mathematics
University of Colorado
Boulder, CO 80309-0395