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Rh saw the edge of the ring as a thin rim of light, and, from some spots seen on it, inferred that it rotated round the planet in 10 hours, 32 minutes, 15 seconds. The planet itself revolves in 10 hours, 14 minutes, 23 seconds.

Highly interesting was the story thus told by the planet; but Herschel wrung from it other details. He suspected that an eighth satellite existed, but it was reserved for others to discover an eighth, and, it is now said, a ninth, at great distances from the planet. But the rings continued to be a puzzle, which baffled solution. He observed lucid points, different from the satellites, coming between the ring and his eye, and moving along it in their orbits. If they were not satellites, what were they? He was not mistaken in "the frequent appearance of protuberant and lucid points on the arms of the ring of Saturn." They were realities, not illusions, not an enchantment lent by the vast distance at which he saw them. "Many of these bright points," he writes, "were completely accounted for by the calculated places of the satellites"; but there were many more which remained inexplicable. He could not entertain the idea that these points "would denote immense mountains of elevated surface." He rather inclined to the belief that the ring was in a state of rotation round the planet, and that one at least of the shining spots might be a moon bedded in or somehow connected with the ring, floating, it might be, in a fluid like water, or running in "a notch, groove or division of the ring to suffer the satellite to pass along." He was perhaps not far from the truth in these romantic imaginings. But the light of the ring is generally brighter than that of the planet, and he even imagined that the shining spots