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belts. Herschel established the rotation of
the planet in 1775-94. From observations
during one hundred rotations he found the
period to be 10h. 16m. 0s., 44. Herschel
also measured the ratio of the polar to the
equatoreal diameter as 10:11.
The ring was a complete puzzle to Galileo,
most of all when the planet reached a posi-
tion where the plane of the ring was in line
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